Bogen CHB-20A Rebuild

[K O'Connor]

Hi Guys

Actually, the ultimate fix is to have the machine make a staking tool that fits into the press directly. One of my customers did that for me and it works perfectly. handy to have a lathe and tools that cut steel. Of course, they can make the staking tool out of tool steel, which is very hard. Give them the Keystone part as a guide for the working end.

Trying to square up an irregular-axis hole is next to impossible without either a proper lathe or milling machine. It is unlikely you could do it with a drill press and a drill table tool lock.

Have fun

[physics]

Right yeah, I remember you mentioning that. How long do you recommend making the tool stick out of the face of the ram?

There is a local machine shop with good reviews who handle small jobs, I think I'll see what it'll cost to 1) square up the hole on their fancy machinery and 2) make a dedicated tool.

Thanks!

[K O'Connor]

Hi Guys

Personally, I would not bother with trying to modify the adapter. If the hole in it seems crooked demand a refund. The alternative would be to shim it with the tape just so the staking tool is solidly mounted and won't shift, then figure out the angle to the bed required. Presumably the press will only be used for eyelets?

I would only ask the machine shop about making the production tool. It is way simpler and faster for them to do, so would be less expensive than the other deal. Why a square hole in it anyway?

[physics]

Sorry for the confusion, it's the bore of the ram not the bore of the adapter bushing that is crooked. I thought that the ram came stock with a bored hole so I didn't check for bore squareness when I bought it used. It appears now that the ram bore isn't stock, and it was DIY'd.

As to why I'd have the hole in the ram squared, it was in part a pre-emptive measure so that if I think of anything to do later with the press (you mentioned flanging captive nuts?) I can put whatever tool I need into the squared hole. Also, I thought it might be easier and cheaper for the machine shop to square the hole first before making the custom staking tool. Otherwise the custom staking tool will need to have a kink in it since the portion of the tool sticking out of the ram will need to be at an angle to portion inside the bore of the ram, and I'm not sure how easy that would be to mill/spin on a lathe. Since the exterior of the ram is square from the factory, they could just(?) chuck the ram into the lathe/mill and start cutting. But, I'm not a machinist so what do I know. Figured I'd ask the shop what they recommended cost-wise.

The other thing I was thinking was to shim it, like you mentioned. In this case since the bore of the ram is what's crooked, that'd mean using a drill to add some play to the fit between the bore and the bushing and then adding the shims between the two. If that doesn't work out though, them I'm left with a too-big hole, and not being a machinist I don't know how fixable that would be.

[K O'Connor]

Hi Guys

I think the root of one confusion is referring to the "squared" hole rather than the "re-aligned" hole.

Can't you bring the press back to the seller and get a refund? Whoever drilled it must have tried to do it by hand.

If you are going to talk to the shop, bring the intact press instead of just the ram so they can take it apart and see that the ram is not tapered on one side or other, in case that caused the crookedness of the center hole. Certainly if they can redo the hole straight, then it will be easier to use your coupler and/or shim tape to align the stock 1715. Still, a machined part to fit the straightened hole would be the ultimate fix - or fixes.

I was lucky since the guy that made my staking tool also gave me a press. I found an identical press for about $100 and set it up for smaller eyelets, and then a slightly larger one for swaged nuts. The latter was to be able to use machine screws instead of self-tap to secure chassis bottoms.

[physics]

Good point on the terminology. I've been saying "squared" in the sense of the hole being drilled at 90 degrees to the face of the ram, but "re-aligned" is clearer.

I could see if the seller is willing to take it back, though since it was a classifieds ad there is no guarantee. That, and it was cheap enough ($80) that even after the machine shop it could still be a better deal than finding the next comparable press on the market. We'll see. Thanks for all your input, I'll see what the machine shop and the seller says. Maybe once I have a quote from the machine shop for fixing the hole I'll present that to the seller to see about a partial refund or something.

Also, just to make sure I'm not barking up the wrong tree, here is a picture of the mounted tool that shows the crookedness of the ram's hole:
   
I assume that's enough to throw things out of whack when swaging, and it seems to roughly correlate with where the defects in the eyelets are, but posting here just in case it's negligible tilt and the issue is elsewhere, yet to be diagnosed.

Thanks for all your input! I'll see what the machine shop and possibly seller say.

[physics]

Ok, the seller offered to take back the press and fully refund me. Nice guy. Later today I'll call the machine shop and see what they'll charge for the work I want done. After that, I'll decide whether I'm keeping the press and fixing it up or returning and finding another. However, I just found another possible solution that's not too bad price wise and doesn't require modifications, so there is a good chance I go with that.

What it is: a small drill chuck with embedded neodymium magnet and stress-bearing backstop. Stick it to the end of the ram, mount tool, start pressing. Originally intended for pin pressing.
https://www.mathews-engineering.com/stor..._Tool.html

[K O'Connor]

Hi Guys

Since you have defective eyelet rolls when using the 1715 in the seemingly crooked hole in the arbor press, you have proof that the arrangement is unusable and that the hole is definitely crooked. You can check the squareness of the ram face against the arbor table using a piece of paper. Bring the ram down to where it would otherwise meet the table and see how the impression is on the paper with a low force - basically trying to make "first contact" rather than a crushing imprint (and maybe see what alien life forms live in the paper?).

That magnetic chuck looks like a good prospect. The downside of it is the lost travel of the press ram. This may require repositioning the handle for a more comfortable arm pull input.

[physics]

Didn't have much luck getting a good visible paper imprint. Also if there are any life forms, they're sneaky enough that I didn't catch any. What I did do though, is check squareness of the ram itself using a combo square, and then squareness of the ram with respect to the work piece at first contact. I need to double check one measurement, but it seems square enough that it's below my threshold of measurability. Worth mentioning, however, that this press didn't come with a solid table base or a daisy wheel table, so I'm using some small bits of bar stock that check out as pretty square with my combo square. There is a hair of daylight on the squarest piece I have though, maybe that's enough to cause issues?

I just called a (per yelp) reputable and reasonably priced machine shop to see what they'd charge to fix the ram hole, and they said it'd be $150 minimum, assuming no special stuff needs doing. They'd have to bore it out, plug and weld it, then re-drill the hole. That's twice what I got the press for ($80), and there is another Dake press nearby for $150 so it doesn't seem like it'd make much sense to have the machine shop fix it. There's also another Dake that just popped up for $75, 1.5 ton, with a solid table, with 2 in more space under the ram than my current one, and it appears to be in excellent condition.

So, going forward, I think I'm going to have a look at that 1.5 ton press, and if it looks good buy it, return the current press, and buy the magnetic chuck to use with the bigger press. There is another idea I just thought of. I picked up a Cambion terminal swager a while ago very cheap (see below), but have not been able to use it since I don't have the right punch for it or a suitable anvil/plate for the bottom of the eyelets. Punches are $100 on ebay, but I'm already near that price for an arbor press. Anyhow, maybe the machine shop can spin one up cheaper and/or quicker, then I'd just need some square bar stock (hopefully getting square stock is easy... machine shop scraps?). Bonus points for using a purpose-made tool for swaging. From quick tests before, there is very little slop, and action is like butter. Hmm... I think I'll see about getting some metaphorical toast for that metaphorical butter, and then I'll be in business.

Not my picture, but this is basically my cambion press (though the pictured one is missing a part or two):
   

[physics]

Alright, I checked with the machine shop and they said that to make a tool for the cambion would cost $100 in heat-treating alone if I wanted hardened steel like the cambion tool I showed them. Soft steel, $150 at least because of the time to measure and program a CNC machine to make the part. Basically, while they are entirely capable of making it, it's not economical for me to do a one-off. Ebay's  $100 price tags are looking a bit better now...

I checked out the 1 1/2 ton press, and it's in pretty good nick so I bought that and returned the other one with the off-center hole. I appreciate the seller offering to take it back, it's helping me stretch my project funds further. The old press was a Model 00, the "new" one is a 1990's Model Y. No missing parts that I can tell, and the ram is much more stable then the Model 00 I just returned (probably due to missing parts?). It also has a solid table under the ram instead of a cutout, and it's square. The ram face has some light wear on the sides making it not square on the edges, but the majority (and center) of the face is square. Now, I decide whether I buy a tool for the cambion on ebay or the magnet chuck for the arbor press.
   

[K O'Connor]

Hi Guys

I ran into a similar problem with my previous chassis vendor, who had a fairly limited shop as machine shops go. I am more used to there being every kind of machining tool in such a place, with skilled people who know how to use it all.

I wanted some holes countersunk. They did everything with their punch press - CNC controlled. They could do a "burning" process to make a counter-sink and showed me a picture of the result. By no stretch oif the imagination would anyone call it a "countersink" nor would they approve the result. It turned out they could get a special punch for their machine that would make the required shape of hole, they just resist doing that because the punches are expensive.

Even with that, they routinely forgot to countersink certain holes and I had to do that myself. I never found the correct machine-screw angle bit, only wood-screw angled bits.

The machine shop guy who made my staking tool just used a lathe. It is easy with any lathe to copy the shape of an existing piece, even if it is the end face that must be copied. The blank is placed in the jaws of the lathe and the cutting tool set up to cut on the axis of the rotating blank. The piece being copied is aligned in parallel with the blank and a probe locked into the cutter holder follows the contour of the 1715, in this discussion. My dude might have free-handed it as the tool was not identical but works excellently.

If you contact a different shop with access to "primitive" tools, they may be able to make the tool a lot cheaper and quicker.

[physics]

Thanks for the tip, will do! I had expected that they'd do just what you said, so was surprised when they said they would CNC it. But I'm not a machinist, so I just figured I was wrong. At your suggestion though I looked into the other machine shop I was thinking of visiting and it appears they advertise the fact that they have manual tools for one-offs and prototypes, so later on today I'll see what they say about making me a tool for the cambion.

Thanks!

[physics]

The second machine shop wanted to do it on CNC too, said they wouldn't be able to do it by hand. So I called a third shop, this time specifically asking if they had a lathe and saying that I was looking for a cheap one-off not a pricey CNC-perfect part. Turns out they don't have CNC machines at all, instead running things old school. I popped by, talked with the machinist, he said he can do it for around $60 with about a three-day turnaround. I left the cambion press, the 1715 tool, the cambion tool, and some of the eyelets. We'll see how it turns out in a few days. Nice shop, the machinist actually offered to give me a tool he already made, but it wouldn't fit the cambion press. He said material for making the new tool would be free though, so that's cool.

[physics]

Picked up the tool today, pretty slick bit of work. Fits the cambion press, closely mimics the 1715 tool (was free-handed though I think, it's slightly different), and didn't cost a ton. Unfortunately I'm still having issues with bad swages. I'm guessing it's an issue with the eyelet being off-center with respect to the center line of the punch? I've attached a picture below to see if anyone knows what would cause this. I just lowered the press until I felt a little bit of give, then removed the eyelet. I've had this sort of issue with everything I've tried so far. Hand-tapping with hammer, using the arbor press with the screwy tool hole, using the big arbor press without the hole and manually holding the tool, etc. Oddly enough I was able to get some nice looking swages by using a center punch to flare the eyelet shank using the arbor press to apply pressure, then using the arbor press ram to flatten the flare outwards, then flaring, then flattening, etc. It seems like a symmetric flare is key to a good swage. Anyhow, picture:
   
I'm reasonably certain that the tool itself is secure in the cambion press, but I could always check again and probably should.

Thanks for any input.

[physics]

Alright, I've done some further investigation (read: squishing eyelets with my face a few inches away), and I think I have a better idea of the failure mode.

Conclusions before the details: Both the custom tool and the keystone tool don't have optimally-sized center cones to flair the eyelet sufficiently, at least not without very precise placement but maybe not even then. The result is that part of the eyelet tube won't be quite flared enough by the time it contacts the flat part of the tool meant to roll over the flare, and it will deform similar to how the eyelet would if you just squished it between two flat surfaces. Now on to my test procedures.

My test setup is that I take either the new cambion punch or the keystone 1715 punch and set them pointy-end-up on my arbor press. I then set an eyelet on the tip of the tool, shank down and pre-rolled end up. The idea is that I'm flipping the swaging process upside down so that instead of putting the eyelet against a flat surface and driving the punch down on it I'm putting the punch against a flat surface and driving the eyelet down onto it. As long as everything is secure (read: gravity doesn't mess with things, things don't buckle) I figure the upside down version is equivalent to the right-side up version. The advantage of having it upside down is that I can easily see how the eyelet is deforming against the tool.

Ok, here are the tests I did:

Tools used are a Dake Model Y arbor press, a Harbor freight 1/4" transfer center punch, keystone 1715, and the custom version of the 1715 I had made for the cambion press. Eyelets are keystone 44, which have a shank diameter of around 0.121" if I recall.

Test 1: I setup the custom tool upside down in the arbor press with the eyelet as described, lowered the press until it touched the eyelet, made as sure as I could that the eyelet was square to the ram face, and then eased down the ram. Most of the circumference of the eyelet rolled, but one part looked like it first moved out, then rolled. That part had the defect seen in pictures above where the edge of the eyelet roll is folded back on itself.

Test 2: Same thing as above but with the 1715 tool. Same results.

Test 3: Same as test 1, but I first flared the eyelet shank with the 1/4" center punch. Not to the full width of the punch, but just until it looked flared to some degree all away around the eyelet. This time when pressing, there was first a short portion of low resistance while the flared edge of the eyelet flattened against the bottom of the punch, and then an extended portion of higher resistance until the process was done. The roll turned out well.

Test 4: Same as test 3, but with the 1715 tool. Same results, except since the 1715 doesn't have a pronounced flat spot the resistance was constant through the whole process. Roll turned out well.

I did each of the above tests a few times to make sure I could get consistent results, and I did get highly consistent results.

Test 5: I placed an eyelet on the table of the arbor press shank-down, and brought the ram straight down on it. No punch involved at all. I applied pressure just until I felt it give a little, then checked the eyelet. The eyelet shank deformed so that it was oblong, and the edges started to roll inwards. Picture below.
   

Test 5 was performed after I recalled what the eyelets that I squished in the press for fun looked like. Oblong. The same way the eyelets with defects seemed to have part of their walls go oblong before finally rolling outwards.

Some other observations: 

When I flared the eyelets with the center punch before setting them down on the roll punch for tests 3 and 4, the eyelets once on the punch did not touch the center cone, or if so only just.

When flaring with the center punch, it was possible to flare too much and cause the eyelet to split. So I had to be careful with the press and not over do things.

The conclusions, or at least running hypothesis I have now after these tests:

Eyelet walls deform oblong and roll inwards when compressed between two flat surfaces.

With both tools, the eyelets undergo some of this oblong deformation with (my) standard use.

The oblong deformation points correspond to the defect points of the eyelet.

If the eyelet walls were flared more or more evenly before reaching the bottom of the punches, they'd cleanly roll outwards instead of deforming into the oblong shape and gaining the defect.

A taller (wider?) center cone in each punch would flare the eyelets more and if the dimensions were right result in a clean roll every time.

I'm interested to hear what the rest of you think about all this. It seems like I'm the only person who's dealt with this, so I'm wondering if there is something else in my setup I haven't found yet that is the source of the issues. I'd think that if the Keystone tool was the issue they'd have changed it, or there'd be more chatter on the internet about it, so I'm doubtful of my conclusions.

Based on my experiments so far though, I'm thinking about going back to the machine shop and requesting that they slightly modify the end of the custom tool so that the cone runs a little deeper and wider into the face. There is space for that on the tool, so hopefully it just takes a few more minutes on the lathe to remove the material.

That's all for now, thanks in advance to anyone who provides feedback!

[physics]

Before having the part modified, I think I'm going to try and confirm that alignment isn't an issue. I finally dug up instructions from Keystone (pdf), and it seems that alignment of the eyelet axis and tool axis is very important. So far I've just been lightly bringing the tool down and letting it move the eyelet around under it into alignment before bearing down it, but I don't know how reliable that is.

[K O'Connor]

Hi Guys

Frankly, I've never seen anyone have so much trouble installing eyelets.

As stated in my posts above and by Keystone:
A proper hole size for the eyelet is very important.
Proper alignment of the staking tool with the eyelet is paramount.

You have a drill press now, so you should be able to have proper holes that have square edges and that are round. It seems crazy to highlight roundness when using a rotary drill bit, but the press should eliminate the hand-held wobble of the drill, leaving only the wobble of a poorly mounted chuck in the mandrel of the drill press as an error source.

As you found, the eyelets will stay in the drilled holes and not fall out when you flip the card over.

The alignment of the eyelet with the tool is a bit of you moving the card into place and the tool participating - but mostly it is you. It comes down to a little bit of practice and then it is second-nature.

Note that Keystone says to use "light pressure".

I just had a look at how a #44 eyelet sits on the 1715 tool. The eyelet sits on the cone about 1mm or so up from the circular groove. The eyelet sits similarly on the tool I had made, but the cone is taller and the groove is a touch wider. Using either one just by hand makes a perfect roll in a 1/8" hole.

One other issue would be the card thickness. I use 1/16" stock. There are longer eyelets for thicker material and shorter ones for thinner. There seems to be some missing information regarding how much of the eyelet shank should protrude through the material? I thought there used to be some.

You mention your Cambion press - is it just a brand of arbor press? A few decades ago, one of the suppliers in Toronto carried Manu-Press, which was a whole line including a press that did not look anywhere near as sturdy as the arbor press you have, plus a bunch of dies and holders. It seemed more suited to pressing cheese

[physics]

Hi Guys

Frankly, I've never seen anyone have so much trouble installing eyelets.

Indeed, it's struck me that this seems like an abnormal amount of trouble I'm going through. Especially given that everyone else

As stated in my posts above and by Keystone:
A proper hole size for the eyelet is very important.
Proper alignment of the staking tool with the eyelet is paramount.

Thanks for re-affirming alignment, I'll focus on eliminating that as an issue. Most of my tests (recorded or otherwise) have been done without a board to avoid having to go through a bunch of fiberglass stock and because I didn't get any better results with the board than I did without the board, but if hole size is that important maybe not having the board is screwing with things. I'll start trying more with an actual board. Suppose I could use it as a breadboard of sorts after with all the eyelets it's gonna have.

The alignment of the eyelet with the tool is a bit of you moving the card into place and the tool participating - but mostly it is you. It comes down to a little bit of practice and then it is second-nature.

Note that Keystone says to use "light pressure".

Think I'm gonna have to drill a bunch of holes and try this out. I've tried in the past without luck, maybe there was a feel thing or something I was missing. The "light pressure" thing tips me off that something is wrong with what I'm doing or my setup. I wouldn't call the amount of pressure I've needed to apply "light", and I assume that's because instead of just rolling the eyelet walls I'm causing them to deform as mentioned before.

I just had a look at how a #44 eyelet sits on the 1715 tool. The eyelet sits on the cone about 1mm or so up from the circular groove. The eyelet sits similarly on the tool I had made, but the cone is taller and the groove is a touch wider. Using either one just by hand makes a perfect roll in a 1/8" hole.

I checked, and my tools are about the same. I also tried to use them for hand-swaging with a small steel block as a hammer and that well with nice swages. The custom tool is harder to do the rotating motion with close to the board due to having a wider face, but I don't think that matters.

One other issue would be the card thickness. I use 1/16" stock. There are longer eyelets for thicker material and shorter ones for thinner. There seems to be some missing information regarding how much of the eyelet shank should protrude through the material? I thought there used to be some.

I'm using 1/16" as well. I think I know the info you're talking about, I remember seeing something related to that when I was choosing which eyelets to get.

You mention your Cambion press - is it just a brand of arbor press?  A few decades ago, one of the suppliers in Toronto carried Manu-Press, which was a whole line including a press that did not look anywhere near as sturdy as the arbor press you have, plus a bunch of dies and holders. It seemed more suited to pressing cheese

It's the terminal swaging press that Cambion Electronics sells for swaging their eyelets, turrets, etc. I think Midland Ross also sold it at some point judging from ebay listings. I don't know much more other than it's cast iron and uses a cam and lever for mechanical advantage instead of the rack and gear that an arbor press does. I think this is the page for it: http://www.cambion.com/terminal_swager.aspx. It feels pretty sturdy, though would benefit from being bolted to my workbench.

Thanks for your input!

[physics]

Small update after drilling a bunch of holes in a FR4 sheet and attempting to install eyelets in it with the cambion press while paying close attention to how aligned it feels under the punch and using the cone to help guide my hand:

I got a couple almost-perfect eyelets in a row, then a bunch of messy ones, a split one, and then a few pretty good ones and one nearly-perfect, possibly perfect one.

Some more observations:

The cambion press expects you to mount an anvil or something to the base so there is extra space besides just the punch travel distance, and I've been using a small aluminum block in that space as support for the eyelets and board. Not the most secure, and I think that might be a source of error. It's also not optimally sized for the board thickness (it's a little too tall), and the punch is most secure in the cambion near the end of it's travel (no radial movement whatsoever), so maybe that's an issue as well.

Going forward I'm looking at either getting the keystone tool holder and anvil stuff to mount in the Cambion press base with a spacer (after double-checking measurements), which should provide a secure base with adjustable height or alignment. Maybe finding something else with appropriate height and a wide enough base to provide a secure backstop for the eyelets in the cambion press. Or, getting the magnet chuck for the Dake arbor press. Hmm...

In the meantime, at least I know I can get good swages by hand.

[K O'Connor]

Hi Guys

You cannot test your setup without using real cards.

The Cambion and any setup that requires a bottom holder is not the right approach for eyeleting a card - it may be okay when setting eyelets into floppy material, but not for a card.

Most arbor presses come with a flat thick steel bed which is preferably polished so the eyelet card can slide freely on it. The area of the bed should be about 4-5" deep and wider than the base of the press. There are metal supply places that cater to small builders and hobbyists, carrying every type and shape of metal in appropriately sized pieces and lengths. They will usually cut stuff to size if needed.

The arbor press will definitely work better bolted to a sturdy table even though you do not have to apply high force to install eyelets.

Regarding the card layout: have you seen the inside of an old Fender? The layout is designed for the parts to be used, arranged in now classic shapes that make recognising the circuitry very easy. The point is really to use the space wisely with a minimum of jumpers on the card. Generic cards with two or three rows of eyelets or turrets makes tracing and repairs much more difficult later even though it looks neat.