The AM Forum

I'm about ready to add a modulation scope to the Tucker transmitter. Its a BC-sized rig and I can not easily remove the front panel from the unit. By that I mean there are some 100+ screws that have not been out on 56 years. The screws are some special countersink type, I don't think the OM intended for this to ever be taken apart.

The panel is about 33" x 28" x1/8 or so thick. Its too big to clamp to a drill press because it will flex and that will foul up the fly cutter, been there and done that.

The 5" Tektronix CRT wants to go where the center chart is, in the bottom section of the RF deck under the tube socket - above the panel with the row of meters.

The hardest part for me is always the panels. I only have one chance to do this right.

One friend suggested I could draw a circle and then center-punch and drill a bunch of 1/8" holes, then use some large old dikes to clip out the thin webs between the holes, then file it. I could do that in place..
Does anyone know an easier and more precise way to do this without removing the panel?

Is there any kind of punch that size, like a giant chassis punch I'd turn with a wrench?

I am thinking that you can Drill a pilot hole, Then use a caliper to run the hole out.  Then use a Dremel to cut out the hole.  Tape off the panel of course.  An hour or so, you should have the hole. Its slow going but will work. 

Do you know anyone in the electrical contracting business?  They sometimes use large hydraulic
punches to cut holes such as what you need.

Greenlee makes punches up to 6".

As I mentioned in the other thread, the largest I have is a 4" with a ball bearing draw stud.

The draw stud takes a 2" wrench to turn. I have an 18" Crescent wrench for that purpose.

When you look up the price of a 5" punch, be sure you are sitting down.

+1 on the hydraulic knockout solution, if you can beg/borrow/rent a hydraulic Greenlee set.   It's a 5 minute job with one of those, including drilling the pilot hole.  5" punches aren't easy to come by, however.  I wouldn't try this with a wrench-turned punch because with all the torque you run the risk of bending the hell out of the front panel.  A hydraulic punch puts no lateral torque on the work.

Clark's idea is a really good one too, but if you don't have an escutcheon or bezel to put over it the hole will be a bit ragged, because the Dremel cutoff wheels obviously only cut in straight lines.  I've done this exact thing in chassis where I've needed an odd-sized or square hole.  With a 5" diameter hole you should be able to get it looking pretty good.

Be careful though, the disks have a habit of catching in the work and shattering.  Get the fiberglas reinforced cutoff disks, they're by far the best for this sort of thing.

I would do it with the circle of holes.  Cut the sections between holes (aluminum) with big dikes.  Then file the hole out to the correct diameter.  You need to put drop paper (taped in place) in the rig and on the front panel to keep chips and filings from getting into the works.  The holes are drilled just inside the diameter needed.  For 5" diameter you could drill 1/4" holes, 1/8" holes would take forever.  Cover the hole area with masking tape and draw the circle on the tape.

With a steel panel, the 1/4" holes are better.  You can use a thin triangle file to cut through the spaces between holes.

You need good files and the right ones to get the job done, but it does take a little time to do it right.

If the panel is aluminum this process is easy.  If the panel is steel, then it will be somewhat harder to do.  Be glad you only need one hole.

Greenlee punches for 5" holes are very expensive, then they will be conduit punches that are not standard diameters.  Maybe a 4" conduit punch may come close to 5".  I'll check my Greenlee catalog for exact dimensions of the punches.

Another thing to consider is the shock to the nearby components doing all this drilling and blasting

Fred

As others have said....I would drill a series of holes in a circle, cut out the center, then using a drill motor, get a large drum sander with mandrel from Lowes and clean it up. I've used the large Greenlee hydraulic punches and they work well on smaller holes but they leave a deformation around the circumference of the hole....it sort of looks like a bullet going through metal, the edges of the hole are bent towards the direction that the piston moves.....and the hydraulic oil always leaks and make a real mess.

Bah.

They sell hole saws in 5" size.... you want a very heavy industrial hand held drill, the type with the handle coming off the side, one that runs SLOW and has high torque.  Needs to have a big Jacobs chuck. You want the arbor with the HEX end in ~3/8" size. Add lube, cut slow. About 5 min later you will have a clean 5" hole.

Of course if you add a bezel you can cut it with anything...

                   _-_-bear

I would go with Bear!

Just change the pilot drill from the hole saw to a bit of silver steel the same diameter as the drill - this will stop the pilot from chewing the hole larger, and allowing the holesaw to wander.

A suitably place vacuum cleaner hose behind the panel should help catch the worst of the swarf.

I think if it were me, I would remove the panel - a 5" hole saw in a big drill is going to vibrate like mad - they arent exactly a precision tool.....

Good Luck though, a nice addition to the rig, and a nice turned aluminium bezel would finish the job a treat.

Sean

That's a good point on the deformation, Dave.  Hopefully 1/8" aluminum won't deform too much - but there IS a hell of a lot of force acting on that punch.  In any event this isn't really a viable alternative unless he can borrow or rent one - the punch and hydraulic actuator would probably run north of $500 together.

The worry that I'd have with the hole saw or circle of holes methods would be the same - deforming the panel - especially using dikes to cut 1/8" aluminum.  With a 5" hole and a hole saw on 1/8" aluminum you'll have to put a fair amount of force on it to get it to bite.  And a whole mess of holes would just beg for one to walk off and skitter across the panel... I *know* that would happen to me if I did it  ::)

You could do a combination of Clark's idea with the Dremel, and the circle of holes method - instead of using dikes to cut the webs between the holes, use the Dremel.

I wouldn't do work like this with the panel on because any method is going to create some conductive debris that is going to go where you don't want it.  Even the hydraulic punch method is going to require drilling a center hole and the other methods are going to create a large amount of bits of conductive aluminum all going where you don't want them.  Just think of what ends up on your shop floor in a typical drilling operation and visualize that all going into your transmitter.

No matter what method you choose I would remove the panel. I have a 34" radial drill press in my wood work shop that will drill to the center of a 34" work piece.  Any chance you have a friend with one?  This would allow either a fly cutter or hole saw to do the job with the panel properly clamped with a sacrificial wood back piece providing support to prevent deformation.

If you do plan to work with the panel in place and you can't come up with a punch then I would use a good quality hole saw and a Milwaukee Hole Hawg (or similar quality equivalent).  The Hole Hawg is a heavy duty drill commonly used by electricians and plumbers for getting between studs where large holes are needed.  It uses a heavy duty single speed motor with a 2 speed transmission providing a lot of torque at its low 300 RPM speed.  The handles can be set up in multiple ways to provide good leverage.  You will find many uses for this <$300 tool around your home.  I recently used mine with a paddle for mixing grout.

Check that both the drill and hole saw have minimal runout before use because significant runout will result in a larger than stated hole diameter.  A quick test in a sacrificial panel (could be plywood) will tell the tale.  Do not apply excessive pressure while cutting or deformation and hole size increase will occur.  Kerosene is one of the old standby drilling lubricants for aluminum and I guess WD-40 would do since it is mostly kerosene. 

If you do have to work this in place consider attaching something behind the panel to catch the debris.  I would want something sticky (mouse catch pad?) that will capture all the debris.

I think no matter what you do some tests on scrap before attacking the real panel.

I see the screws.  Whew.
Spray 'em all before attempting removal!

If you try the hole saw, I like the drill the pilot hole, then put in 1/4" rod to replace the pilot bit. That and the 300 rpm or SLOWER drill (Hole Hawg), the
FPM rate on the outside of the 5" dia saw will be faster than you might think.

No matter what I think you are going to want a BEZEL when done.

You could make one pretty easy, or get a sacrificial one off an old scope, like a hamfest beater Heathkit, etc...

I think that unless you like the patina of that old paint, IF you pull the panel, maybe a repaint is in order? Fresh screws in black oxide? Dunno.

What's the toobe line up?

                                  _-_-bear

PS. think OUTSIDE the box - put a solid  "shaft bearing" into the center point where the pilot hole will go on the panel! You can make one by just carefully drilling
some steel of say 3/8" or 1/2" thickness (maybe thicker!) for a very close, tight fit to the 1/4" rod that replaces the pilot drill - now you have a solid center. Of course you have to make say 2- 3 holes to mount this affair, but it can just be a rectangular block (for example) of steel and put the screws out a way and in a spot where you can get to the back side for nuts (use lockwashers!!!) This will help get a very clean hole.

Think 1/4-20 tightened HARD.
When cut through the whole thing comes out together.
The whole saw has about a 1" or better cutting depth, so you can make the "bearing" as thick as you can to that depth minus the cut depth - that will make a really stable setup, I think.

With all the comments,  if that panel is 1/8 aluminum I could have made the hole in probably an hour.  I've made meter holes many times using the circle-of-holes method and I have a complete machine shop but still do them the old fashion way.  I also have many Greenlee punches but they can distort the panel.

Drilling the holes does make a lot of chips, you have to mask off the area to catch the stuff.  Also put some masking tape with the sticky side out around the hole (like a cup).  That will catch most of the chips.

Use two drills, one with a small drill to start the holes, then another with 1/4" drill.  Heavy sharp dikes will cut the remaining sections out.  Then you must use a half round files to bring the hole out to the correct diameter.  If you don't have files, it will cheaper to buy them rather than the Greenlee punch.  They make files with rasp like teeth (like ones used for wood) that will file the hole easily. Remember, you can never have too many files.

I have a box full of scope bezels if you need one, they're either HPs or Tectronics or both.

Fred

Let me offer these ideas.
The circle of holes method is a hobbyist approach and looks like it unless done with absolute care.
The amount of handwork is laborious.
Does the Tektronix scope have a finished bezel? Why not use that same finished look by either incorporating the bezel already manufactured for the scope, or make your own. This would not only make it an attractive professional looking installation, but would mask any imperfections made by boring the hole.
A 5" hole saw using a small amount of cutting agent and a slow speed drill would be far more effective than the circle of holes method. You would have to set up a means to insure the drill is evenly applied parallel to the cutting surface so it wouldn't dance. Once the circle is started and the cutter is digging in properly you would be able to keep and maintain the feel of the cutting. I would make a blot using an old thirsty cotton towel to absorb the cutting agent (marvel mystery oil) and keep things tidy.
Once the hole is cut, you can use de-burring tool to chamfer the edge of the cut on both sides of the panel.
Make a bezel plate from the same type of 1/8 panel stock or sheet metal. You could even fashion a hood from another scope. Better yet, if you plan on using a Bezel, you wouldn't necessarily have to cut a round hole, it could be square. The Bezel would make the hole appear round cosmetically. It could also be made of plastic or Lexan, which could be painted to taste.
Just another perspective.
Good luck.

I can remove the heavy RF deck so it will be easier to clean out of metal chips no matter what I do. Its easy to work on from the underside.

I already have a few bezels from deceased scopes as well as mounting hardware for the CRT and shield. The bezels have a slightly smaller opening that the CRT size. If the hole can be sized so its edges don't show, it won't matter if they are not 100% perfect.

The CRT is a NOS one for a 545A. I chose it for the brightness. It has a 10KV Ultor as opposed to most modulation scope CRTs using 1000-3000V.-The thing takes a few extra voltages but the manual seems helpful. It should be easy as CRT power is very low current and a tapped bleeder with pots on it is the basic way. It has a 6.3V heater.

The real challenge is the hole, lots of good advice here on that. I need to measure the CRT outer diameter precisely, sure it is not exactly 5". Ideally the CRT should just fit through the hole so its face can be against a graticule. If not, then the graticule must be put behind the panel with the CRT and the bezel out front as usual. At this point there is no decision on whether to illuminate a graticule or even use one. That's not as important as getting the hole done.

Perhaps an unorthodox method, but since you're going to have chips where you don't want them anyway, I'd use a Trim Router with a spiral up cut, flush trimming bit, and a template.  This method will give you a nice edge, and most all the effort will be in making the template, which is expendable if you screw it up.  Make the template as large as practicable, then attach the template with double side tape.  Make sure the panel is clean when you mount the template so you have maximum adhesion of the tape. 

This is exactly what I did on this GR attneuator, and this is the trimmed raw edge as the router left it.   I bought The attenuator as a rack mount version and used the faceplate of my other one, as the template.

(http://i670.photobucket.com/albums/vv62/mikeinkcmo/testgear/GR/1450%20Step%20Atten/GR14508.jpg)

I'd advise having a drop cloth or old sheet on the floor in front of the cabinet.

That's why I suggested using the hole saw. 99% of the wasted material would be on the outside of the panel, therefore not making it such a hazard on the inside.
If you cut a square hole, all you would have to do is bore a pilot hole in each corner, and use a Sawzall with a narrow bi-metal blade. I have done this with excellent results but you absolutely have to plan ahead and figure a way to capture the cuttings on the inside.
The hole saw approach has the advantage of not making such a mess on the inside of the cabinet. If you plan on using a Bezel, then consider using one that would allow you to move the CRT closer the the front edge allowing better visibility of the graticule. A 5" inch hole saw may have a slightly larger outside diameter than the OD of the CRT.

Get a good Bi-Metal hole saw and 1/2"arbor. It will cost about $35 at the most. Use a variable speed 1/2" drill minimum. Use masking tap and cover the cutout area. Go SLOW and don't let the pilot hole "wallow out'. If this happens it will cause problems - GO SLOW! Make sure the panel is secure.

It won't take that long and won't be near as bad as you think - I  "thought out" ( read dreaded) cutting a 4 1/2" hole for 2 weeks and was amazed at how easy it turned out and how quickly it was done.

A router will definitely work. but it needs a very solid center hold down if you use the circle cutter approach. Use the smallest carbide bit you can use for the job. It will make copious sliver type chips... Using the router with a follower bit is a good option, make multiple low depth cuts with either approach.

Think I have tried all the known methods.

The best method I know of is to let someone else do it! :p

                   _-_-bear

I would use a hole saw given that you can't remove the panel.  However, I would make a hardwood guide first. Use some oil and turn SLOW!

The hardwood* guide is simply a board through which you've already sawed the desired hole.  Clamp this board firmly on (across) the panel to guide the hole saw through the metal panel. This eliminates the wander that a large hole saw will exhibit. The 1/4" pilot hole will end up 3/8"+ before you're done otherwise, with the accompanying ragged hole.

*Soft pine is usable if you must but if you're clamping across a 19" panel I wouldn't use less than a 1"x 10" plank. Plywood will work as well.   

Ditto!
Hard Maple would be a good choice for hole guide. Less likely to have hole "run out" from the bit.
By the way, a good quality arbor/hole saw combo will greatly contribute to the outcome of the operation.
The arbor's that I have use a short shank drill for the pilot. This means the actual twist cut of the drill is shallow and is designed so that during the drilling event, unnecessary material removal doesn't occur after the initial hole is established. This helps to minimize making the hole more oval while cutting the 5" area.
A slow and deliberate cutting action will produce the best result, given a steady grip.
Remember this, if you use a hole saw, you HAVE TO use a cutting agent! Not only does this aid in helping the saw cut a smoother hole, but helps to keep the temperature down. Maintaining these requirements gives the best results.

We have used routers with carbide cutters here at work for years to do architectural anodized alminum. It works OK, but..........

You got to have a steady hand and a strong grip to hang on to it. It wants to jump all over the place if you don't hang on tight. A milling machine would be a much better choice.

You MUST use a cutting agent. We have used this stinky-assed stuff called "Alumicut" for many years. It smells nasty, but sez it's "non toxic" all over the label. It is fantastic stuff. It works by preventing the cutter from loading up with aluminum. It even makes filing it a joy 'cause the file doesn't load up with shavings. Also works fantastic on a simple old hacksaw. It also makes a hell of a difference tapping aluminum 'cause the tap doesn't load up. "Tap Magic" for aluminum also works pretty well, But I prefer Alumicut.

For drilling and cutting stainless steel we used to use a mixture of denatured alcohol and mothballs. It's purpose was to keep the tool from heating up.

after you drill the pilot hole put steel rod in place of the pilot drill in the hole saw so it won't deform the hole. Go slow

Also, I forgot to mention, using the external wood guide permits re-cutting an existing opening where no material for the pilot exists. It's great for putting new locks in old doors. :)

Cut a square hole in the panel...larger than the scope. Easy ....use a saw.  Then make a square pc that has a round hole that fits your scope to fit over and trim out the square hole that you cut with the saw....all the work of making the round hole (however you decide to make it) can be done on the bench or the table of the drill press

Maybe buy one of these, and get a couple bits that will hack away at the metal.

Fab a guide (wood, maybe) and stick it to the front with double-sided tape so this thing has something to ride around in.

Even if it just does one job, it is worth the coin....

Use your shopvac for the 'collateral damage'

http://www.sciplus.com/singleItem.cfm?terms=16852&emailid=176&trk_msg=42QRGKS4E79498C2A58G6PJQIK&trk_contact=9IFJEI7JC00BD8S8H4G4E5TS3G&utm_source=Listrak&utm_medium=Email&utm_term=Product+Details&utm_campaign=American+Science+%26+Surplus+-Our+final+holiday+sale+email!

73DG

If that was mine Id lay that rig down so your pushing down from the top. A 1/8" aluminum panel is mighty thin but the drill and hole saw held at that level is asking for trouble if you want precision. I dont see any easy way of mounting a hardwood guide either.

Carl

The cut out saw in the link looks pretty good. I didn't realize there was a tool like that.

As for laying it down on its back, ouch my back!! with the large iron out it is 1000 lbs. However, after all this good advice, one thing is decided, the RF deck has to come out. That is a royal PITA but it is only about 100 lbs and can be laid on its back.

This got me thinking that with the RF deck on its back, on the bench, the small drill press here might be able to center over the right spot on the front, seeing it is near the bottom of the deck. I would not mind temporarily bolting the press to the work bench for this job. Slow speed on that is about 500-600RPM, a little fast for a 5" hole saw. I also have a Milwaukee 1/2" drill with the side handle that can go really slow. Its got lots of torque. Still thinking about this.

The available bezels will hide any ugliness of the hole.

In the past I used alcohol to drill aluminum, but kerosene was mentioned. Which is best? Neither is a lube, what is the goal in using these liquids?

For this job you will need Tap Magic.
It really is magic...I was sceptical at first but it really works!
I use it for drilling holes, tapping and anything else that requires work with aluminum.

Well, have you drilled the hole yet??  I know we've been talking about it for a week.  I could have made five of these 5" holes already.

If I wasn't afraid of rattlesnakes and tumbleweed I would come down to Texas and get it done. ;D

Fred

No, I have not yet cut the hole. I work long hours (I call them "half-days") and until about 45 minutes ago was working. When I post here in the evenings, I am actually logged in and working because I work with not only the USA co-workers, but those in France, Italy, Poland, India, and Singapore. So, Saturday and Sunday are for the projects.

Sorry I am not moving very fast but I still must measure the CRT diameter and select the tools based on that. A 5" CRT is not 5 inches in diameter. It is in almost all cases slightly larger and that falls between tool sizes. Many steps and lots of thinking to do a good job, haste makes waste except in field-expedient work.

The holidays are coming and that may be a great help when my colleagues that "provide opportunities for me to excel" will also be away from the lab, customer, and office.

If I did not have to work, I would probably be ready to do it, but the last bit of good advice arrived at 22:39, so why start cutting before all the experience has spoken?

Right now I am looking at 5", 5.25", and 5.5" hole saws, that might be the thing.  - -will measure the CRT maybe Saturday. -certainly not Tuesday (today) yeesh look at the time, time for my 6-7 hours.!

zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
Need a round tuit for this.

Consider a 70% water, 30% Joy soap mixture in a squirt bottle for your drilling/cutting fluid....No solvents, oils, etc and it moves/floats the swarf from an alum cut with a hole saw...keeps the tools cool,easy clean up...cheap too

Ive been using that for over 20 years and the standard version for steel for a lot longer. A little goes a long way.
When I have to waste a lot of fluid I use Oatey Dark Thread Cutting Oil and buy by the quart.  It really saves drill bits.
 http://www.oatey.com/Channel/Shared/ProductGroupDetail/95/Dark+Thread+Cutting+Oil.html

Aluminum is soft and really doesn't need a cutting "lubricant". Lubrication is not the issue. The purpose of using a "cutting fluid" (Alumicut, Tap magic, bee's wax, kerosene, etc) is to keep the aluminun cuttings from loading up (sticking to) the cutting tool. Once the tool loads up with cuttings the friction heats the aluminum and it trys to melt itself back together. Giving a crappy cut or breaking the cutting tool.

Once the tool (drill, tap, saw, etc) loads up, it tries to beat it's way through the cut, leaving a pretty nasty edge. I have seen more guys break drills and taps off in aluminum than any other metal. (cutting dry) Because they were bound up with cuttings. I have used Both fluids in the past to free up taps that someone else had bound up in a piece of aluminum.

Even putting a few drops of Alumicut or Tap Magic on a file makes filing a simple job instead of a chore.  Great Schtuff! ! ! ! !

If you use Tap Magic, MAKE SURE you get the kind meant for aluminum! The kind for other metals will boil and bubble and turn the aluminum black.

If you can find a nibbling tool that will cut 1/8" thick aluminum, that would be a great way to cut your hole. Maybe a sheet metal fabricator would do that for you.

Patrick, they make those hole saws in 1/16" increments!
But they are not stocked by everyone.
An industrial supply Co. tends to have them all...

I would use the slow speed on the drill press and not hand hold, just take very light pressure cuts, pull out when it gets hot, add lube, go back...

make sure there is no shake or give in the set up and that the deck is square and flat to the plane that is the cutting face of the hole saw.

Bingo! Done.

                       _-_-bear

PS. I would NOT use the cutout to hold the face of the tube, UNLESS you put "catepillar" grommet over the edge of the cut aluminum, or some similar rubber to interface to the glass. So I am saying make the hole strategically bigger, or hold the tube from behind... (cradle)

I dug out my big Greenlee set, and the closest to 5" I have is the 5" conduit, leaving a 5-5/8 hole. :)

PM me fer th' dope.

73DG

For big holes these work great!...

http://www.tools-plus.com/malco-hc1.html

It still makes lots of chips but does a nice clean job and the price is right!

What speed do you rotate that device at? Looks like a lot of mass out there swinging in the breeze at 16 oz. Plus 0.054" Al is quite a bit different from 0.125" Al. Have you ever used it for 1/8" Al or are they just being conservative? Looks neat, but I have to admit to having a bit of a reservation given the length and weight.

You hold it by that handle after drilling a centering hole. The adjustable center pin rides in the centering hole and the only part that rotates is the drill bit at the end that's being driven by the power drill. Once it's in the centering hole you drill a starting hole with the bit and then swing it around the centering pin with the special side-cutting drill bit cutting the circle.

I haven't used it on 1/8 inch alum. but there is no reason that it won't. I'd just go slow. There is a guide clip that rides under the edge of the cut that may have to be spaced out by a couple of small washers or just removed (two small screws). Spare bits are about $9.00 and you only wear on the part of the bit that is cutting sideways; when it gets dull in that area you just move it up or down a little bit in the holder.

If I can find time tomorrow I'll give it a try on a piece of 1/8 scrap. I've used it mainly to cut round holes in sheet steel duct work for round take-offs.

My bad, Greg. I was looking at it backwards -- thinking flycutter -- silly me. Makes perfect sense and all reservations withdrawn. I may have to get one if your test on 0.125" Al proves out. Forgive my temporary (I hope) idiocy.

ldb

Got the PM!

Well, it's not real intuitive at first glance.

The guides I was talking about are really only spacers to keep the tool level and spaced properly; they won't need adjustment. I think this thing will do up to 1/4 inch aluminum if you move slowly. With regular ductwork I can cut a 6 inch circle in about 30 seconds.

I'll give it a shot tomorrow; with pictures.

This hole was cut in .080" alum in 4 minutes, including the pilot hole and a couple of stops for pictures.

(http://img827.imageshack.us/img827/3708/dscn2190s.th.jpg) (http://imageshack.us/photo/my-images/827/dscn2190s.jpg/)

(http://img834.imageshack.us/img834/1382/dscn2194n.th.jpg) (http://imageshack.us/photo/my-images/834/dscn2194n.jpg/)

(http://img17.imageshack.us/img17/8673/dscn2195fk.th.jpg) (http://imageshack.us/photo/my-images/17/dscn2195fk.jpg/)

(http://img33.imageshack.us/img33/7733/dscn2199m.th.jpg) (http://imageshack.us/photo/my-images/33/dscn2199m.jpg/)

(http://img585.imageshack.us/img585/1721/dscn2201w.th.jpg) (http://imageshack.us/photo/my-images/585/dscn2201w.jpg/)

(http://img847.imageshack.us/img847/6517/dscn2204n.th.jpg) (http://imageshack.us/photo/my-images/847/dscn2204n.jpg/)

This 2 1/8" meter hole was cut in 90 seconds, including the pilot hole. That little tab at the end of the cut can be filed or you can just stop most of the way around and clamp a piece of wood on both sides to keep the center piece in place.

2 1/8" is the smallest hole it'll make. It'll cut holes up to 12"...

(http://img585.imageshack.us/img585/8762/dscn2206cv.th.jpg) (http://imageshack.us/photo/my-images/585/dscn2206cv.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

(http://img861.imageshack.us/img861/6052/dscn2204h.th.jpg) (http://imageshack.us/photo/my-images/861/dscn2204h.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

(http://img822.imageshack.us/img822/3348/dscn2208wj.th.jpg) (http://imageshack.us/photo/my-images/822/dscn2208wj.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

For fifty smackers that thing is the way to go!

Looks like that jig does a really good job.  I thinking that a end mill can be use in the same manner.  End mills are designed to cut on their side.  I may make a jig set to cut 2-1/8 meter holes using an end mill.  I have a panel that needs four 2-1/8 meter holes.

Fred

A 5 minute job if you have EZ-TRAK on your Bridgeport, Fred.  Of course, the setup, clamping, etc will probably take 3X that  ;D

If anybody is interested in Greenlee 700 series Radio chassis punches, have a look on page 48 of the December 2011 Electric Radio. It's in the want ad section and a Michigan ARC is selling 5 sets. A total (by my count) of 45 punches. Round punches of every size as well as square, rectangle, keyed and double D. Each of the sets are priced between $50 and $70. About the price of one punch purchased new. Most are new in original boxes. The used ones are like new says the club representative. Looks to be an estate and the club is a 501(c)3.
Contact oldbugger@copper.net or 269-382-5401

I have no connection with this sale.

I still want to see the results with a .125 or .250" panel

I have no doubt that it would work just fine, just a bit slower, but I don't have any sacrificial piece of suitable metal to try it on at the moment.

I may come up with one next week when I get back home.

If I can't clamp the unit to the 15" rotary table on my mill in some fashion, I would simply use a saber saw on a hole that large, followed by a drum sander to get it to the edge of the scribe mark.  A slab of foam taped to the backside helps to collect the swarf if you have room, and some painters' tape on the front will eliminate scratches from the saber saw base plate.

There are a lot of excellent videos of sheet metal working ideas at http://www.eaavideo.org/video.aspx?v=595068183001 if you are interested in such things.  There is very little new under the sun when it come to metalworking, and radio fabrication is part and parcel of aircraft construction as well...

Merry Christmas,

they were sold. I imagine those people have been flooded with calls.

hooray! Sunday I get to try to punch it.

Initial testing with the CRT shows it will be OK. Got bit by the 10KV/1mA supply! (actually a -1500/+8500 arrangement just like in a 545).

no joy yet. chores + no time.

Punch?
or cut?

Hmmmm... inquiring minds want to know!

                  _-_-bear

You cut that hole yet??????

punch - this weekend assuming I got or can buy or borrow a wrench big enough, the drive is a monster.

Ok, I got only so far. I have to get a 2" wench to turn this any further. The 14" channel Locks are not slipping but are merely too hard to turn. A 2" wrench will do.

1. a square makes sure the center punch will be in the center of the RF Deck panel R to L.
2. double check with a tape. It is a 30" panel.
3. checking after scribing a little vertical line, how the CRT will fit. The large hole has to be moved to the side 1" or the punch won't be able to be put there to do the 6" hole. OK fine I can balance the final appearance by putting the CRT control shafts in that space. They will be plastic and long going to the rear of the RF deck away from other things. At this point the owners of Tektronix 535's and 545's may begin to complain that I am wasting a NOS CRT that could be a spare for them.

4.To get the center of the CRT, an old graticule was drilled just big enough for the center punch.
5. The graticule and bezel were placed in the best spot and the center punch did its work.
6. After a 1/8" hole was drilled, the backside of the punch was held in place to make sure it would fit properly. I chose to move the hole 1/4" vertically to clear a chassis rail.

7. Next the small punch was used to make the hole for the large one's shaft.
8. The large punch was fitted in place. The papers are to protect the panel.
9. the other side.

10. starting the real work. It is not very easy and a real wrench is needed.
11. the backside, it has not popped any of the points through yet. I'm told that once it does it will get easier but I can only put so much force on pliers, they don't slip but I can not keep them on and push at the same time, nothing moves, so its time to get the proper tool for turning the large nut. The small nut (flats) has not tried to turn nor been a problem.

hydraulic power pack would be nice..Lookin good...keep on going...Nice pics..

Harbor Freight is a cheap source for big tools that won't get used very often.

73DG

One can never have too many wrenches.  I have them up over two inches.

You are going to really chew up the nut on that punch with those pliers.  Try to borrow a wrench from someone.  Maybe a local garage can lend you one.

Fred

Some auto parts houses rent rarely used tools and test equipment. Might find a 2" wrench for rent. Beats buggering up the punch.

Patrick,

You mentioned something earlier about how many screws involved in removing that panel. Until I saw those pictures I didn't understand the problem.

That's a ton of hardware. That rig takes "Drilling and Blasting" to a whole new level!

Mike

A drop or two of oil or grease on the threads and if you don't have a 18 inch crescent wrench use a pipe wrench.Use to punch a lot of holes in stainless steel and the threads on the bolt would get galled if you ran them dry.Hope it works out.Joe.

Do you know any diesel / construction equiptment mechanicks???  They have the large drives/wrenches.... 

vice grips and a piece 'o galvanized pipe?

klc

A few months back I needed a 1 -7/8" combination wrench and 3/4" drive socket the same size. This was for a large machine installation where there were lots of leveling screws with big 1.875" nuts to loosen and tighten over and over until the thing was aligned to better than a 1/10th of a degree. The Grainger folks fixed me up for $140 plus tax.  :'(

 If I recall, the socket was much more inexpensive than the wrench.

Jim
WD5JKO

I cannot overemphasize the importance of Joe's advice.  The proper lube for the threads is an extreme pressure EP grease, because it can sustain enormous thread loads.  Any EP lube with molybdenum should work fine.  I don't know of any oil that would be very effective - it gets squeezed out of the thread to thread junction with the pressures encountered.  Better than nothing, but a ball joint or similar grease will do fine.

No I won't chew up the nut. The punch is not mine so I can't afford to make a mess of it. I know when to stop with those kind of pliers, otherwise I would not have posted that I am going to get a wrench. It's all in the strength of the hands and I had hoped the pliers would provide enough advantage to get the teeth through which is always the hard part but no I have started to bend the handles of the pliers. Pliers like that must never be allowed to slip, and the limit is when the handles start to bend. It should not be too hard to find a 2" wrench in Dallas, might be expensive or have to be borrowed or rented, but with today's fuel prices and the value of time, just buying it may be better than running all over town to borrow and return one. I already have a 1 7/8" one.. why not get a 2".


The threads being tightened are almost 2" and are well-lubed per the instructions but not with EP grease. It should not be hard to pick some up when wrench-hunting on Monday.

I hope a wrench is easy to find and the rest of this goes well. I appreciate all the good advice on this!

5" punch + 2" wrench + 1/8" material = King Kong torque required to turn it! ! ! !

You might want to consider a hydraulic operated punch, or a 3/4 or 1" drive impact wrench to turn it!

That punch I loaned Pat has the ball-bearing collar that really eases the effort.  He has complete instructions I sent along as well.

You can't use an impact, or any other socket-type wrench, as the big punches have a compound thread system, and you need to use two wrenches on them:  one to hold the pull stud, the other to turn the pull collar.  Otherwise the pull stud will bind into the punch threads and cause problems.

I use a 20" Proto 'Crescent' on those jobs here at home, or if it fits, I put the whole thing in the 30-ton press and do it the easy way.

Like I said before, Harbor Freight has big tools (like wrenches) for sale cheap, and they will do a fair amount of work before they wear out.  He should go there if he can't borrow one.

73DG

The 2" wrench is here. It is from Harbor Freight and is 22.75" long. They sold me a 6-pc set of 1-3/8", 1-1/2", 1-5/8", 1-3/4", 1-7/8" and 2" for $36, but online the same thing is $44. ?? price increase?

It is about a 0.125" panel, more like 1/8" not 1/32 but I have not measured exactly, maybe it is 0.100 or a 'gauge' size.

OK well tomorrow I have to travel to San Antonio for a LASER experimenters' meeting and it will last until Sunday AM, so this weekend is out.

OK, Patrick, we'll just call this the intermission and all go out and get some popcorn and Junior Mints. Awaiting your success story of the monster hole punching event. Have fun at the laser meeting.

I'll sneak this in here, but won't let this stray off topic because the CRT and hole job is what it's all about! And it should be done tomorrow Monday because I'm off work!

The laser meeting was a real success! Never seen anything like it as technology has sure progressed since my last messing with professional visible lasers.

The hands-on was great, everything from lumia homebrew techniques to alignment of galvanometer servos! - it is still an analog technique requiring back and forth tweeking and an understanding of the basic principles. Then there was setup and a full automated laser show with at least 8 projectors that I know of. And fog, this was in a room about 60x60.

I won door prize #2, a 447nm (deep blue) OEM laser module rated 300mW CCS. It was donated by Aixiz. More cool because I never win - last time was  that brand new IC-2AT and OSCAR-Locator at a hamcom. Even more cool because Jacob was with me as a guest and he was chosen to pick tickets for the door prizes. The #1 prize was a Pangolin laser show system. Someone else won that, so I called out,"Jacob, I need that laser!" and he did it.

The module has an analog input for modulation, don't know the input bandwidth yet. 447nm = 670GHz though. I need to buy some goggles before messing with it further.

This has been a public service announcement. We now return you to the "Vicarious Hole-Punchment" Channel. Stay tuned for part two: "The Chinese Wrench".

Success!

Armed with the 2" wench, the hole has been punched. Even with the leverage it was not so easy, but it is better to have taken it slow than to force it. There is a video of the wrenching but it is 226MB so it needs shrunk and posted later.

It is as if that punch was made for this CRT. Big thanks to Dennis, and to all that offered advice.

I can not use the existing shield because it is too close to the tube socket so i would like to find a more form-fitting one. I guess we will see later if magnetic fields is an issue.

Greenlee to the rescue! :D

I bet there was quite a 'pop' when the last cutter went through... :o

73DG

Very nice, Patrick. Looks like it grew there.

There was no real pop, it was a soft 'tink' sound. There was also no real deformation of the panel. The panel is just under 1/8" thick. The piece that came out is a good candidate for wind chimes because it rings nicely and now has an interesting 3-D shape.

Thank you for the good comments on the job! It could not have been as tidy without the punch.

The bezel shown there will probably be the one used. It fits the standard Tektronix bezel bolts. In the old scope that was cannibalized here, those seem to be pressed into the front panel. That scope has two front panels apparently in inside one and a nice looking outer one. I am not sure how the bolts might be removed to be used in the transmitter.

Nice job OM!

I can't wait to see that trapezoid.

Patrick,  great job,  after everything was said and done the trusty Greenlee punch did the job.

Good thing that Dennis had one that large.

Fred

Looking good!

That was but the second documented use of that giant.  I did a speaker hole in a panel a few years ago with it.

It looked unused when I bought it, no wonder as 5" conduit is not that popular.  It was part of SK consulting engineer Dick Haskeys' estate.

Holey panel, Batman! ;D

73DG

If it jams, force it, if it breaks, it probably needed replacing anyway................ :o  ;D

(Murphy 1:14)

speakers.. Maybe I should do a little more punching before returning that. I regret having sold the old 5" rackmount speakers. Not that they sounded that good but they worked and looked great in flat black. Paper cones with whizzers!

I had a few minutes today and mounted the high voltage CRT power supply and mocked up the location for the transformer for the low voltage portion.

The CRT circuit was under discussion here:
http://amfone.net/Amforum/index.php?topic=31066.msg242335#msg242335

- But the schematic's changed a bit again. It's a little tricky balancing the voltages because of the very low current (2mA DC total) of the power supply transformer. With the voltage divider passing so little current, things like X and Y position pots and connections to the other (5400V) supply can upset the voltages.

Back to the mountings, I have to buy some 1/8" thick 3/4x3/4 aluminum angle to mount the LV transformer.

Each transformer/box weighs 5-6 lbs. It's worth mentioning that capacitor clamps with small tangs that fit over the ridge at the power supply's top are weak in that area. Tightening the bolts actually will straighten them out, 'flow' them around the steel ridge and loosen the iron.

They would be fine for a light weight capacitor, but I am not as pleased with them in this service where the object to be clamped is heavy. My worry is it breaking loose at some point and striking that costly and special CRT.

The picture shows each of the clamps has two small tangs. I would prefer to find some with a larger and continuous tang. Wider is better.

If anyone has some. At least 3 are needed. (entered in 'wanted')

Like a can opener?

Nice!

A can opener, being made of steel and properly prepared, would have eventually cut the hole.

The tube is in. What a slow project but it is moving.

Looking good, Patrick.

Thanks!

Here are the attach points. The brass screws up front worked ok. I am not sure I like the appearance but they work well. The front of the tube was some 0.07" smaller than the hole and it rattled so I wrapped 3 turns of some thick but soft nylon tape around the edge and it fits perfectly and somewhat cushioned without binding. Later I can redo this using the correct shield and the tube will be partly supported by that. The tape came from a trailer full of military junk. I don't know where it can be had.