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Elgin HM-5C horizontal w/ penumatic feed

leeko

Stainless
Joined
Jun 30, 2012
Location
Chicago, USA
Hi everyone,

I posted this over in the antique machinery forum, before I realized there's a specific forum for these. Mods, feel free to delete the other post if necessary, thanks.
___

I just won an auction for an Elgin HM-5C horizontal mill, and am pretty pleased - I'd been keeping my eyes open for a small horizontal for a while.

The mill as pictured is set up with pneumatic (hydraulic?) power feed, which looks pretty clunky. But, I've seen at least one other example that looks essentially identical so I'm wondering if it was a factory accessory?

I've never used a mill with pneumatic power feed, and I'm too impatient to wait till I pick it up, so I have a couple of questions for you guys [emoji4]

- is the power feed likely just for the x-axis? (Not sure if that's evident from the single pic I have)

- is a power feed like this useable/practical in a home shop environment? I'm assuming it just needs an air supply, with relatively modest CFM requirements?

- if it's not practical to use it, how easy would it be to remove and go back to manual/handwheels? I'm guessing it should just be a matter of sourcing missing handwheels, but just wondering if this type of feed ever involves irreversible modifications to the mill?

Thanks in advance! I'll make sure to update the thread once I get her home.

Lee

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I assume that is an air/oil setup. Otherwise the speed would be uncontrollable. The biggest problem with that arrangement is fine positioning in X. I think you would be better off finding a leadscrew for the X axis.
 
Egh, that's what I was hoping wasn't the case...

Any idea what the dimensions on the leadscrew were for this machine?

Thx

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The air over hydraulic system is very useful in a production shop. For manual machining, a screw feed would be best. Might be easier to trade the machine with a production shop. The next easiest solution for home use would be to make a cable drive.
CableDrive.jpg
The attached photo is a Hardinge mill that we converted from screw drive to cable. A lot of horizontal mills have a rack and pinion drive for the x axis, but the cable drive will be a lot easier top fabricate from scratch.
 
Hi Fred,

That sounds really interesting. Does the cable drive allow you to stop at a precise location? Or is it limited in that respect, much like the lever feed or air-over-hydraulic?

The screw and nut are missing on the way to mine as expected.

Thanks

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We have a t slot in the table just above the base. We use it for stops at both end of the travel and is very repeatable.
The stops can be seen in this video:
CutTubing - YouTube

The round one is used to actuate the vise control valve, the one behind the hose in the middle of the video stops the table, precision in this tube cutting was not needed but the stop is short and rigid and would repeat very well if needed.

I used an air over hydraulic feed like yours in the first shop I worked at. They could be set very precisely with some time and effort. For making one and two parts at a time it would be very frustrating. When doing production scrapping a few parts during set up is expected.
 
Egh, that's what I was hoping wasn't the case...

Any idea what the dimensions on the leadscrew were for this machine?

Thx

Sent from my SM-N920T using Tapatalk

Whatever your measuring tools of choice tell you will FIT into the space and you can find at an affordable price? EG: Aftermarket. MMC or such. Forget factory OEM. Too old. Too rare.

Not personally a fan of it, value-for-money-wise, but since you have to do "something", SOME folk would go for ballscrew and servo CNC'ish.

Might as well keep what is there as go down that road.

Other's might go with rack & pinion.

Key is to not over-do the spend, lest simply shedding it in favor of another horizontal mill be more attractive.

Horizontals do go cheap.
 
Hi Monarchist,

Thanks for the input. I'm thinking I should just replace things with a leadscrew and nut.

Can anyone advise on whether it matters if the screw and nut are RH or LH for the X-axis? As far as I can tell, it would just change the direction the handwheel works, is that right?

On MMC, the acme threaded rods seem cheap enough but the threaded nuts are significantly more expensive.

There are many cheaper options for ballscrew conversion for the various mini mills out there. From what I understand, ballscrews can be used on a manual mill as long as the gibs are properly adjusted to provide a little friction. Is there any reason not to go that route? It's certainly a lot cheaper.

Thanks again,

Lee


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Some people disparage ball screws on manuals but there are some that come stock that way. I've used a CNC Bridgeport that was converted to manual and still had the ball screws. I loved it due to the ability to climb mill, just had to be in the habit of locking down whichever axis you weren't currently using.

For a conversion line yours, I'd probably consider using ball screws, especially if it came out cheaper.

Teryk
 
Thanks Teryk, that more or less confirms what I've read. I think that's likely the way I'll go.

Cheers,

Lee

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Hi Monarchist,

Thanks for the input. I'm thinking I should just replace things with a leadscrew and nut.
That's usually easiest, and no, on a MILL, direction is largely about what you are "used to". Lathe might be more picky as to following convention...

In this case, "used to" is nothing. Yet.

BTW: If you rob electronic calipers for DIY DRO, the screw need not even be uber-precise.

Even so, I would do. Or a GOOD ballscrew setup. It is a nice mill in a handy size, may as well be a precise one, and a delight to use, too.
 
So, I set about removing all the pneumatic gear tonight, to try to figure out what size ballscrew to order. It all came off without any trouble, and I was able to slide the table off.

I'm a little confused by what I found. The portion of the saddle that the table rides on has a through-hole that measures 5/8" at each end. But, around 1/2" in from the right side the diameter necks down to a 7/16" threaded portion.

Is that likely the nut for the longitudinal axis? 7/16” seems like a weedy size for a leadscrew on this machine, and I believe the traverse leadscrew is 5/8”. In addition, the threads look to have a v-thread form from the little I can see of them - I would have expected acme or square thread like the hardinge um/tm.

If anyone has been into one of these machines, or even a hardinge, I'd love some guidance. I'm thinking the next step will be to remove the traverse handwheel, leadscrew, then slide the saddle off to get to it's underside to look at the nut...

Thanks,
Lee
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If anyone has been into one of these machines, or even a hardinge, I'd love some guidance.

Go and download the manual written for the US Army for the Burke #4, AKA B-100-4.

Not as nice a mill as either the Hardinge or Elgin, but same basic size, and pretty much the same mechanisms. More of us have - or have had - the Burkes and Hardinge T-wotever than the elusive Elgin, so yes - worst-case, someone can get an eyeball or camera onto their comparable bits and pieces.

The Burke manual, plus what you have right in front of you, should help.

That 7/16" thread, for example, is probably for a retainer/adjuster to a bronze bearing, with thrust face running on the reduced-diameter and polished end of the leadscrew.

The (Acme, stub-Acme..wotever) "nut" will move along the leadscrew, be anchored to the slide below. Same with a ballscrew.

We don't want the leadscrew running in and out of either end of the table to hang out all vulnerable, after all. It stays hidden under the table.

:)

Think of a lathe's carriage turned upside-down. The compound rest becomes the knee, the cross-slide moves the saddle. No leadscrews are exposed, either end of travel.

Your Elgin had no leadscrew for the long-axis table.

It WILL have an example, probably the same screwthread, end bearing, attach philosophy, even the same sizes, under the "in out" slide below it.

Bit of luck, mayhap even interchangeable parts you can try on the top table, then copy.
 
Hi,

Thanks for the pointer to the Burke manual. I think I'm probably being dumb on this, but the Burke table and mechanism looks pretty different from mine. On the Burke, the dovetails are the opposite (male on the table), and the table is cutaway to allow the leadscrew to sit in a recess underneath. Similarly, the nut is fastened to the saddle and is therefore stationary.

On my Elgin, neither the table or saddle have a recess for the screw or nut to reside. The only place I can see for the leadscrew would be to go through that 5/8" center hole in the saddle, but the reduced diameter at the right side would mean that a long section of the leadscrew has to be less than 7/16” diameter to pass through it at the extreme end of travel.

In your post, you mentioned that the reduced end diameter of the leadscrew would likely bear on a thrust bearing retained by that 7/16" threaded area. But later, you stated that my Elgin had no leadscrew for the long axis table. I'm confused!

I'm hoping this will all become clear once I get the saddle off. But, I can see the traverse leadscrew under the saddle and it's 5/8” diameter throughout it's length.

Thanks again. As I stated, this is almost certainly my failure to grasp something fundamental.

Lee
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Full disclosure here, I've never worked on, nor operated, an Elgin mill before. Having said that, is it possible that the 7/16 threaded part is a shop made insert that was installed to hold the accuating rod of the piston? I'm looking at the hole and it appears that there are threads there that a lead screw nut could be installed into. Just a bit of a guess on my part. :)
 








 
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