# Wohlhaupter UPA 5 guts



## JRaut (Dec 22, 2020)

I recently acquired a Wohlhaupter UPA 5* that I plan to sell off for a few extra bucks to put back into the shop. These things are combination boring / facing heads. Meaning: it can work like a regular boring head. But if you grab onto the collar while it's spinning, it'll automatically feed the slide out (or in), allowing you to face with it. The UPA 5 can actually turn tapers too if you use it with the auto-downfeed of your machine. The outfeed is stepwise-adjustable in twelve increments between 0.0008 and 0.0096 in/rev on the radius.

More out of curiosity than anything else, I cracked'er open to see what makes it tick, and cleaned it all up in the process. A few hours in a hot ultrasonic bath did the trick. By my count, there are at least 142 individual parts making this up. Mine is missing a few of the clamp screws and stuff like that, but none of the bits that make it work.

Figured you folks may be interested in some of the photos. I'll take a few more as I re-assemble it to show a bit better how the mechanism works. There is a little bit of info out there on the smaller UPA 3s, but very little on the UPA 5. So maybe this'll help someone out of a jam some day.

The first photo with everything assembled isn't mine; I just grabbed it from the internet. The pictures of the guts are mine.












*I also acquired a Wohlhaupter UPA 3, which I plan to keep. Disassembling / cleaning that one is on my to-do list as well. Maybe I'll post some similar photos if there's interest.


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## francist (Dec 22, 2020)

Yeah I can see how those might be pricey....
Wow, that’s a lot of bits.


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## Aukai (Dec 22, 2020)

Scares me, and I'm fearless. I would go nuts if I heard something hit the floor, and couldn't find it.....


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## JRaut (Dec 22, 2020)

Yup, scared me too! I count 20 springs or so in total --- any one of those could have sent a who-knows-what flying.

But I took my time and was extra careful. Kept subassemblies grouped together in small mason jars, etc.

I've got some Wohlhaupter-approved grease on order, so it'll be sitting around my shop disassembled for a few days before I can get it back together.

Better lock the door to keep my 3yo kid outta there... he just got a new tool box and is keen on using it.


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## 7milesup (Dec 22, 2020)

JRaut said:


> Better lock the door to keep my 3yo kid outta there... he just got a new tool box and is keen on using it.



I guarantee that if I left it lay I would kick it by accident.  I guess if that happens you can employ your little guy to crawl around the floor and find every bit'n bob.


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## 7milesup (Dec 22, 2020)

JRaut said:


> . These things are combination boring / facing heads. Meaning: it can work like a regular boring head. But if you g*rab onto the collar while it's spinning*, it'll automatically feed the slide out (or in), allowing you to face with it.


Errrmmmm.  How about not!  LOL.
I's sure once you have done that it would be fine, but it sounds wicked scary considering the size of that thing.
Awesome piece of tooling you have there Jeff.


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## mmcmdl (Dec 22, 2020)

These are nice pieces of tooling  I kept my smaller Wohlhaupter and my larger Narex and sold all my other plain boring heads .


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## JRaut (Jan 8, 2021)

Well, after stripping it all down, I gave it a good, long bath in the ultrasonic cleaner.

And after my order of Wohlhaupter-approved grease arrived a few days later, I put it all back together. No extra pieces, and none of the pieces went missing along the way. That in and of itself was a great success.

Here are just a few more photos that I took while re-assembling. The mechanism basically works like this:
- The upper collar has a series of 12 plungers arranged around the perimeter.
- Any, all, or none of those plungers can be manually activated by the user by pushing it in from the outside (two detent positions, in or out).
- When activated, the plunger protrudes through the inside of the collar.
- To perform a facing cut, the user holds the collar stationary as the boring head swings around.
- Each time the head goes around, each of the activated plungers 'trips' that star wheel and advances it 1/5th of a turn.
- The star wheel, in turn, is meshed through a gear-set and a worm-set to advance the slide of the boring head, thus achieving a 'facing' operation.
- More activated plungers means faster facing.
- Also in the collar is an auto-trip mechanism to stop the facing/boring feed; as well as a means to reset all those plungers. That's what you see with that wicked serrated-looking collar thing
- Pretty slick mechanism, if I do say so. Not really what I expected either. The facing advances in small steps rather than as a continuous operation.

Anyway, as I said in my earlier post, I'll probably toss up some similar photos once I crack open my UPA 3.


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## 7milesup (Jan 8, 2021)

That's awesome Jeff.  Thanks for the inside look at some really cool engineering.


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## sdelivery (Jan 8, 2021)

I had three of the Wohlaupter heads....but at the time didn't own anything to use it with so I sold them to Wohlaupter.
Wish I would have kept one..


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