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View Full Version : Conversion of Logan Lathe to Use Automatic Apron



Paul R
10-28-2009, 09:05 PM
Hello Folks,

I have a 10-inch Logan model 850-2 lathe that I bought a few years ago. This lathe was supplied with what Logan calls a "plain" apron assembly, which means it has no clutch (just a split nut to engage on the lead screw). Other lathes that were supplied with the same plain apron assembly include the Logan 200 Series, 850, 1805, 1806, 1810, 1811, and 1850.

My lathe's saddle is broken so I was thinking of upgrading the whole carriage (saddle, cross slide, and apron) to the type that was supplied on the Logan 815, 820, 825, 840, and probably a few others as well. These lathes had what Logan calls the "automatic" apron, which includes a clutch.

The ways on the beds of all these lathes has the same dimensions, so the saddle should be able to fit, BUT when I asked Logan Actuator about using the "automatic" apron on my lathe they said that the relative position of the lead screw was different, so it wouldn't work.

My question is...

Has anybody converted one of the "plain apron" Logan lathes to have an "automatic" apron? If so, what was involved? Did you have to move the lead screw mounts or modify the apron?

Thanks in advance for any advice you can offer!

Paul

J Tiers
10-28-2009, 11:06 PM
Scott Logan has said a couple times, that you would need to move the leadscrew out to match. Don't see why it can't be done, the brackets bolt on.

Might be a pain to do, but.....

Apparently you didn't talk to the right people. Apparently one or more on the lathelist has done it.

Go to the Logan site and sign up for the list , and then ask.

Ken_Shea
10-28-2009, 11:17 PM
What is the difference/benefit of a clutch/split nut engage?

Ken

J Tiers
10-29-2009, 12:09 AM
Well the clutch system referred to drives the carriage via a sliding key in the keyway, which in turn drives the handwheel system, as opposed to driving via the leadscrew threads.

That puts NO wear on the screw, obviously, except the keyway. better threading accuracy, for longer.

Doc Nickel
10-29-2009, 12:28 AM
A few years back, I bought a used QC gearbox to convert my changegear Powermatic/Logan. It had the plain apron, and as I recall, I figured I'd have to shave about 5/16" off the mounting face of the QC box to move it inboard enough to fit.

That was the easy part- the tricky one was shortening the leadscrew, and at the time I didn't have another lathe I could do the work on, so I never got around to it before I sold it.

Now, one presumes you could basically just fab up two 5/16" (or whatever the dimension ends up being) spacer plates to move the gearbox (if you have one) and the right-hand leadscrew support out a bit.

One issue is, if you have a changegear lathe, the left end of the leadscrew is supported by a plate, that may or may not be able to be moved out without some convolutions.

Doc.

Paul R
10-29-2009, 09:59 PM
Thanks, folks, for your replies.

It sounds like the main thing I would need to do is shift the position of the lead screw so that it would fit the new apron. Does anybody have experience doing that on a Logan lathe? Should I expect any difficulties? What was involvved?

Also, I have tried to find the Logan Lathe Group that Iv'e seen mentioned here in posts, but have never been able to find that on the Logan web site. They have a newsletter list, but I'm guessing that is more of a sales flier. Is this group still active?

Thanks

J Tiers
10-29-2009, 10:28 PM
it's on the "contents" page

http://www.lathe.com/list/index.htm

yes it is quite active.

interrupted_cut
10-29-2009, 10:33 PM
Go to http://finance.groups.yahoo.com/group/lathe-list/ and use the "join this group" button. It is a very active group, moderated by Scott Logan.

rantbot
10-30-2009, 01:04 AM
but have never been able to find that on the Logan web site. They have a newsletter list, but I'm guessing that is more of a sales flier. Is this group still active?
There are at least two on Yahoo.

Lathe-list is Scott Logan's.
http://finance.groups.yahoo.com/group/lathe-list/?yguid=119555483

A newer group, without as many members, is Loganlathe.
http://finance.groups.yahoo.com/group/loganlathe/?yguid=119555483

Both are reasonably active. Lathe-list is probably the best place to pose your particular questions, as interchange of parts between models is a hot topic with the members.

PeteM
10-30-2009, 01:13 AM
I used to have a Logan lathe -- and converted it from a plain apron one with a clutch with no problems.

All that's required is to carefully measure the difference in offset between the two aprons and then machine shims for both the feed box and the rear lead screw retainer. The half nuts in the automatic apron are set out further from the ways -- and the shims were maybe around .300 in thickness. I don't recall and I don't have the lathe any more to provide a more accurate guesstimate -- and there might be enough variation to make this individual to the lathe. You can use brass shims for a trial fit so the lead screw ends up precisely where the new apron's half screws want it.

There was enough freedom of movement in the head stock gear sectors to move them into engagement with no problems.

J Tiers
10-30-2009, 08:55 AM
The distance is set by the half-nuts.... where the hole in them ends up is where the leadscrew has to be.

I can't see it being a big problem.

hrhoades
10-30-2009, 05:49 PM
I have a model 850 Logan that I added a quick change gear box and automatic apron to about 2 years ago. I had to mill some off the gear box, drill and tap the bed, use the half nuts from the automatic apron, shim the rear carriage screw bracket, and use the saddle off the a lathe with the automatic apron as the mounting screws for the apron were not located the same.
Hal