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View Full Version : Old Lathe, leave original or add modern VFD drive?



S_J_H
02-26-2009, 07:42 PM
I have been using a SB9A for most of my lathe ops. It's pretty worn out but still does decent work if you take the time to work around it's deficiency's (worn bed).
Right next to it is my Artisan Lathe that sits idle. This machine dates back to the 1920's, possibly a little earlier.
It is in excellent condition. The ways are still in excellent condition and scraping marks are very visible on every surface. It is more robust than the south bend 9" in every way even though it's very similar in size. It can spin 16" in the built in gap.
2 1/8" plain bearing spindle so rpm is limited. No power cross feed. Threading range about the same as the SB9A.
It even has a nifty clutch for the drive shaft.
It's all original.
Problem is the old crowned flat belt pulleys just limit the usefulness of the machine badly.
They are heavily crowned unlike the flatter southbend pulleys. The belt easily throws with to much load.
I feel this machine would easily out perform my SB with an updated drive system. I have a 1hp 3ph motor and VFD sitting around and am thinking of installing it on the Artisan with new serpentine pulleys.
Then the old girl could be put back to work and should be a very nice smooth running lathe I can actually use.
I have only seen 2 others on the net so it's a rare machine. But it was meant to work and make chips and I could use another "useable lathe".
What do you all think, upgrade the drive system or leave it alone?
Here it is next to the SB9A-
http://i109.photobucket.com/albums/n48/S_J_H/compares004.jpg
http://i109.photobucket.com/albums/n48/S_J_H/compares005.jpg
SB back gears-
http://i109.photobucket.com/albums/n48/S_J_H/compares008.jpg
Artisan back gears-
http://i109.photobucket.com/albums/n48/S_J_H/compares009.jpg

Steve

JCHannum
02-26-2009, 08:15 PM
I don't know what the collector value might be, it might be enough to warrant selling the lathe and using the proceeds to finance a new machine.

But, I would suspect buyers would be few and far between. I see no problem with removing and boxing up the original parts and repowering with a VFD and using the lathe as intended. With careful use and proper lubrication, I doubt normal HSM use would damage the machine. Unless you go aboard it with a torch and grinder, it can always be returned to original condition.

alanganes
02-26-2009, 08:31 PM
You will not destroy it in the conversion process, so you might as well put it to use. Unless some collector wants it badly enough to pay real money for it, I'd second the above opinion and make the switch.

That is a REALLY cool looking lathe, by the way.

I have owned a few things similar to that, cool and old, but not wildly valuable, in a monetary sense anyhow. So I tended to "save" them by not using them, etc. I finally came to the conclusion that I do not live in nor run a museum (though I sure would like to!) so I may as well use these things and enjoy owning them, before I'm dead.

I have finally reached the point that once something annoys me, just by being there, it is probably time to get rid of it.

-Al

JND
02-26-2009, 08:46 PM
You did a beautiful job restoring those,as I doubt they showed on your doorstep in that condition! I agree,save the original parts,and make it usable for what you want. I have an old (1929) 13"SB that I have been considering doing the same mod,to have more control over speed. I would do it in a heartbeat,as long as the machine was not dammaged.

tony ennis
02-26-2009, 09:13 PM
Just make the mods reversible. Then put the original parts in a well-labeled box for the next owner.

edit - take lots of pictures and make notes about the lathe before you take it apart. Put the pictures in the box too.
edit 2 - Man, that SB is gorgeous.

wierdscience
02-26-2009, 11:22 PM
What have you tried to make the flatbelts work?Are you sure you have the right type belt for the job?

derekm
02-27-2009, 04:28 AM
VFDs with their ramp start and stop make life easier for old lathes. So as the old girl is getting on a bit you should make it easier for her. Do it.

macona
02-27-2009, 04:37 AM
If its throwing a belt you may have a bad belt or something is out of whack.

You really want to grease up those gears on the artisan though. My dad used some lead based open gear grease on the gears and it runs near silent now.

I would leave it as is. Still has a top RPM of about 500 and I wouldnt run it any faster with the spindle bearings it has. I think I have seen about three others other than ours.

S_J_H
02-27-2009, 11:18 AM
I think I will go ahead and do it. I will not destroy any original parts in the process or modify the machine to add the new drive. The original GE motor and cone pulleys will be stored away.
I will never work or use the machine enough to wear it out. So the next owner will get this machine in excellent condition and if they choose can install the original motor and drive pulleys.

I won't sell it. I like it way to much. I tore it down to every single bolt when I got it. Even the bolts on this machine are original and factory made for the lathe. I checked spindle runout last night with my Brown and Sharpe .00005" indicator. Runout is about a tenth on the chuck register. I mounted the indicator on the carriage about 5" out to the way surfaces measure wear.It drops a max of .0005" over the length of the bed.
Because I won't need to rev it up to high, a direct drive should be sufficient with the 2 speed gear box of the lathe and the vfd.

Macona, the belts I believe are original. Big fat leather belts. With a lot of belt dressing they'll hold pretty good. But makes a mess. I tried a serpentine belt and it worked much better. But the pulleys are still a bit to heavily crowned to work well.
The gears are not greased right now as the machine is not used. Once it is back in action they will be properly lubed.

Steve

S_J_H
02-27-2009, 02:07 PM
I went and started fitting pulleys and planning the swap. Oh , it just looked so "wrong" with a ribbed pulley and serpentine belt.
Can't do it. Something inside of me just won't let me do it do this old machine. It will stay original just as it has been for the last 90 or so years. Just going to save up for a bigger machine.

I managed to keep the belt from slipping off with a little alignment adjusting of the drive shaft. It will take a decent depth of cut now without throwing the belt. .1" in aluminum is no problem and .05" in some stainless. The motor now bogs down before the belt slips off.
So it's probably more a lack of experience on my part with these old cone pulleys and leather belts than anything.


I would leave it as is. Still has a top RPM of about 500 and I wouldnt run it any faster with the spindle bearings it has.

Actually it runs quite abit faster than that. I just installed my tachulator on the Artisan and checked the speeds. This machine has 100% original pulleys and motor.
The actual rpm reading for the 6 speeds at the spindle are as follows,
Rpm= 260- 450 - 800! in high speed range.
Rpm= 39 - 72 - 138 in "back gear" range.

Steve
http://i109.photobucket.com/albums/n48/S_J_H/vintage%20Artisan%20lathe/Artisanspeedtest001.jpg
http://i109.photobucket.com/albums/n48/S_J_H/vintage%20Artisan%20lathe/Artisanspeedtest002.jpg

oldtiffie
02-27-2009, 02:27 PM
I went and started fitting pulleys and planning the swap. Oh , it just looked so "wrong" with a ribbed pulley and serpentine belt.
Can't do it. Something inside of me just won't let me do it do this old machine. It will stay original just as it has been for the last 90 or so years. Just going to save up for a bigger machine.

I managed to keep the belt from slipping off with a little alignment adjusting of the drive shaft. It will take a decent depth of cut now without throwing the belt. .1" in aluminum is no problem and .05" in some stainless. The motor now bogs down before the belt slips off.
So it's probably more a lack of experience on my part with these old cone pulleys and leather belts than anything.

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Good on you Steve!!!

That sure is one very pretty and now very useful lathe.

I am sure you feel a lot better as it is in its original pristine state and useful and will be used - it doesn't get better than that.

I was going to suggest adjusting the alignment of the drive pulley shaft but presumed that you'd thought of it.

It is after all just variation of the "tracking" adjustment on a belt sander under the same circumstances and for the same reasons. An eccentric at one end of the drive pulley shaft should do the job if needed.

Here is my belt sander. The tracking control lever is under the left side of the belt and just forward of the motor. The driver pulley has a slight crown to it. The driven/front pulley is a spirally fluted "rubber" roller which pumps air (cooling) and flexes (to suit the job).

http://i200.photobucket.com/albums/aa294/oldtiffie/Belt_sander1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Belt_sander2.jpg

S_J_H
02-27-2009, 07:35 PM
Thanks Tiffie,

There is very little adjustment on this lathe for belt tracking. But it seems there is just enough to remedy the problem. The motor to drive shaft belt is fine and never throws. The old GE motor is huge and weighs 60lbs or so, has the oil cups and a reverse lever. But it's only 1/2 hp so I should not expect to be able to take huge hog cuts. What I probably need to do is just use the machine more and get to know it better. I have only used it a handful of times since I bought it, tore it down, cleaned and checked it out. The nuts on both the cross slide and compound have tons of play. So I'll need to fix that. Those big huge gears always spin so it's a noisy beast when you have it in the highest speed.

Now what I could do and it would not change the appearance at all, is to just swap in the 3ph motor and vfd and leave the original belts and pulleys in place.
This I may do as it's a simple swap. It'll give it much more power, smoother running and the soft start and stops will greaty help keep the belt in place on start up.
The bed on this lathe is so unusual. It seems to be VERY stable. I can move this machine all over my shop and it still stays very level.
Steve

S_J_H
03-06-2009, 07:34 PM
Well I went ahead and installed a 1hp 3ph motor/ automation direct vfd drive on her with automotive serpentine belts on the original pulleys.

I installed the big flat motor pulley on the new 3ph motor, which is made from some sort of fiber laminate with steel slugs and mounted it on the lathe. The pulley was out about .005".
So I setup a tool bit on the backside of the lathe carriage and turned the flat pulley true while the motor was running.
I used a 8 rib serpentine belt I just happened to have that fit perfectly.

For the cone pulleys I did not have a perfect fitting belt but had one that was to long. I cut it to fit and stitched it together with some stainless braided wire. Running the grooved side to the pulley.
Time for testing!
I made a nice T-nut and installed a QCTP and tried out some carbide tooling on some 2" O.D. 12l14 steel and 2" O.D. 303 stainless.

I did comparison tests to my SB9A right next to it using the same steel and same tool bit. The Artisan will out cut my SB9A and delivers a finish every bit as nice.
The belts do not slip or throw. Very smooth running now and with the vfd it's easy to tune out any annoying speed ranges that cause vibration.
Ol' Arty is going to make a fine useable machine for me now.
Steve
http://i109.photobucket.com/albums/n48/S_J_H/vintage%20Artisan%20lathe/artisansnewdrive001.jpg
http://i109.photobucket.com/albums/n48/S_J_H/vintage%20Artisan%20lathe/artisansnewdrive004.jpg

alanganes
03-06-2009, 08:13 PM
I still think that is one of the coolest looking old lathes I have seen, and beautifully redone. NICE WORK!
Very clever stitching the belt like that.

I really like those Automation Direct VFD's. Lots of bang for the buck.

S_J_H
03-06-2009, 10:28 PM
Thanks Al! It really is a cool old machine. Now I can "really" use it.

I have seen others thread the serpentine belts using fishing line even. I had tried gluing and scarfing but this threading method is a lot better IMHO. No stiff joint and runs as smooth as if it was uncut, plus very quick and easy to do.
I was taking a .125" DOC in the 2" O.D. 12l14 and these serpentine belts did not even give a hint of slipping.
So much for my thinking the pulleys were to heavily crowned. These serpentine belts track dead straight on these old pulleys and transfer the power excellent.

Steve

J Tiers
03-06-2009, 11:15 PM
Good for you!

The way that machine is built, there really is no way to affect the "leveling" or twist, since it has virtually only one "foot". I suspect that was the whole point.

looks like a fine, if unusual, machine.

tattoomike68
03-07-2009, 12:02 AM
Its so clean,, do you make chips?

No way in hell will my stuff ever be that clean.

S_J_H
03-07-2009, 11:09 AM
Its so clean,, do you make chips?



Ha! Can't even believe your asking me that with all the things I build.
Staged photo's and a good wet/dry vac Mike. ;)

Although the Artisan lathe has not been used much. But this thread is all about putting it back into use to make chips. Guess I should have posted pics of it covered in chips yesterday.

Steve