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View Full Version : Restoring Atlas 9 inch lathe: So close but . . .



Paul_NJ
01-12-2007, 09:41 PM
I am restoring an old 9 inch Atlas/Metalcraft lathe that was given me, with the advisement of a number of you on this site. The only part I found “terminal” was one of the bevel gears in the lead screw gearbox. The other two gears in the gearbox were fine. I spoke with the folks at Clausing, and the closest they had was the similar gear for a 10 inch Atlas. It arrived today ($68 later). Best I can tell visually, it has an identical gear pattern, and holding it adjacent to the mating gear it seems to mesh fine. While the 10 inch Atlas has a 3/4 inch leadscrew, and my 9 inch has a 5/8 inch leadscrew, I was told (correctly) the end of the screw upon which the gears ride is the 5/8 diameter, because that in fact is the ID of the gear. So everything fits. See photo #1 . . . Good news!


http://images19.fotki.com/v365/photos/4/490718/3726483/IMGP0767-vi.jpg

But now the rest of the story. The bevel gear top design, that forms the socket that the sliding shift collar mates with, is quite different . . . See Photo #2. For comparison, I'm showing the new gear, and the other "old" gear that is still in good shape. (Hope I'm explaning this well enough)

http://images19.fotki.com/v381/photos/4/490718/3726483/IMGP0770-vi.jpg

What do you think? Can it be modified, ie can material be removed from the “toothed” design to accept the almost half circular shift collar male “tab”. Not knowing better, it looks like if I had a mill, I could open up the teeth to make the same socket design. What do you think? Alas, I don’t have a mill. Is it feasible? Could I ask someone to help me on this? Or should I send it back to Clausing? I’m at a crossroads here and I sure could use some advice/help. Thanks.

CCWKen
01-12-2007, 09:54 PM
Wow! I'd send it back. For $68 I'd cast a new gear myself. What's wrong with the old gear? (Besides a little wear) I use my crossfeed for facing and that's about it. If you want to keep the new gear, I think it would be much easier to make a new shift collar to fit the new gear.

Wess
01-12-2007, 10:29 PM
I'm down in Hillsborough and have a mill, but the question that jumps to mind is if the gear is hardened.

lane
01-12-2007, 11:01 PM
I'm down in Hillsborough and have a mill, but the question that jumps to mind is if the gear is hardened.


I aint Paul but No atlus gears are made of zammick a pot metal material alum. and zink and i dont know what else cuts easy but cant weld.Some body close help this new guy I would but to far away.

JCHannum
01-12-2007, 11:38 PM
If I am not mistaken, those are the two gears which drive the lead screw. The 9" lathe does not have a power crossfeed. The shift collar slides back & forth for forward & reverse of the lead screw. I believe the used gear in the photo is the remaining good gear of the two originals.

Without having the gearset in hand, it looks as though the new gear can be modified by milling to match. It should not be difficult to do on a milling machine, the gears are not hardened.

With that said, probably 90% of lathe work is done with the carriage travelling from right to left, and some lathes do not have a reversable lead screw, reversing being done by adding another idler gear in the gear train. It would not be too much of a loss to simply eliminate the gear box alltogether and use a solid coupling to join the stub shaft to the leadscrew. The reversing gearbox is one of the weak points on the Atlas lathes, and was ultimately replaced with a set of tumbler gears for reversing.

TGTool
01-12-2007, 11:44 PM
Paul,

There's a yahoo discussion group devoted to the Atlas/Craftsman lathes and you might find better specific help there. That group is http://groups.yahoo.com/group/atlas_craftsman/ .

The newer gear is a nicer design for the dog clutch, but the best shot is probably to modify the one you've got to match the old parts. (The alternative being buying another bevel gear and central shift part.) You can actually contrive to do some light milling on the lathe and it might be sufficent for this job, particularly given that the part is Zamak. As a for instance, you could mount the new gear on a short shaft matching the leadscrew stub, mount that in a boring tool holder that has a straight hole, clamp vice-grips to the outboard end and you've got a two-bit rotary table. The milling cutter of course is chucked in the lathe spindle. There's more to it, but you get the idea.

jm

Mike Burdick
01-12-2007, 11:45 PM
Paul_NJ,

Can't tell for sure what would be involved from the photos but is it possible to make a new replacement for the shift collar and match one side to the new gear? The collar seems like it would be easier to make without any special tooling. It also appears to have an integral key but if the new part was made from steel the key could be silver soldered in.

Paul_NJ
01-13-2007, 12:50 AM
If I am not mistaken, those are the two gears which drive the lead screw. The 9" lathe does not have a power crossfeed. The shift collar slides back & forth for forward & reverse of the lead screw. I believe the used gear in the photo is the remaining good gear of the two originals.

Without having the gearset in hand, it looks as though the new gear can be modified by milling to match. It should not be difficult to do on a milling machine, the gears are not hardened.

With that said, probably 90% of lathe work is done with the carriage travelling from right to left, and some lathes do not have a reversable lead screw, reversing being done by adding another idler gear in the gear train. It would not be too much of a loss to simply eliminate the gear box alltogether and use a solid coupling to join the stub shaft to the leadscrew. The reversing gearbox is one of the weak points on the Atlas lathes, and was ultimately replaced with a set of tumbler gears for reversing.


You've deciphered correctly what I failed to explain clearly. The "other" part I showed is the "forward" gear, which attaches to the change gear and drives the leadscrew - I showed it only give a look what the end "socket" looked like on both gears. Here's the way they are arranged in the gearbox:

http://images19.fotki.com/v35/photos/4/490718/3726483/IMGP0773-vi.jpg

Actually there's a third gear on top which I suppose is an idler gear. Excuse the pencils and screws . . just trying to hold the gears from rolling while I took the photo. This old lathe is my foray into metal working which I really hope to use for learning . . .but my only metal experience right now a cutting torch and a drill press: and neither skill seems particularly applicable toward this current dilemma. So making my own gears or remachining the shift collar aren't options. I haven't even run this lathe yet.

But you told me something I didn't know . . . I didn't realize the gear I'm trying to replace is the reverse direction gear . As you said, perhaps I should save the $68 and a lot of trouble, and just use the lathe's forward automatic cutting capability, then shift to neutral, and crank it back by hand with the wheel handle. Gee, am I interpreting the situation and your words correctly? Is there any other reason I'd want to go backwards automatically? If not, then why bother replacing it? Perhaps that's what the previous owner had done all along as the damaged worn gear had been actually turned around backwards on the lead screw.

Thanks

Paul_NJ
01-13-2007, 01:23 AM
I'm still confused. I have a Manual for the lathe, and while it tells next to nothing about how to set up the lathe, it does have a parts blowup. And the blowup labels both gears as leadscrew reverse gears, "left reverse" and "right reverse" gears. Oh brother, what's up with that? (Interestingly those gears cost $.40 back in 1930).

Are we sure the right side gear is reverse and the left forward? I'd sure hate to send the new gear back and discover it was the forward gear.

Mike Burdick
01-13-2007, 02:13 AM
Paul,

Keep the gear...$58.00 is NOT that much. Measure and detail the shift collar and then put the lathe back together with the old parts. Now you can use the lathe to make the collar. Make one side to fit the new gear and the leave the other side as is. It looks like all you'll need is the lathe, a hacksaw, and a file. It'll be a good first project and you'll learn alot. Nothing teaches better than when one "has to do something"! :) Be glad you have this opportunity!

The gear is $58.00 today and will probably be $100.00 when you decide that you need it to make left hand threads, etc. (and you will).

You might have to make the part several times before you get it right, but believe me, after you get the part to work you'll never look at a broken tool the same again. Yep, you'll start thinking junkyards are shopping centers!

kendall
01-13-2007, 02:56 AM
Myself, if I already had the gear in the garage, I'd go ahead and mod it, but if I were buying it, I'd have to look for the right one, unless I could find one that was as easily modded as this one for a lot less.

A Dremel type tool, would work nicely to remove the lugs if you don't have access to a mill, one corner would need file and knife/scraper work to make the corner directly but if all other aspects are the same it should work nicely.


May be better to look for the correct gear, check ebay, and people on the atlas group, someone may have one.

My grandkids played around in the garage and left a gear from my atlas out in the driveway where I ran it over, and someone on PM emailed me and said he had a few gears for the atlas lathes, don't remember who though, and I think I purged my emails, but I'll look.

My atlas has the same reversing box as yours does, keep it lubed, I understand it needs to be turning when switching, and use gentle but firm pressure, everything in there seems to be the same zamak material, haven't broken mine yet, but I'm not rough with it, seems you need to develope a feel for it, mine was difficult at fiirst to engage, but wiuth practice you learn the right pressure. think mine's a 'war' model, no chrome on it anywhere, but every one I've seen that's similar has chrome wheels etc.

The way the gears are set up, if you can not get that box fixed or find the right one, you could place another gear with the same tooth count as the spindle gear in the train to reverse the leadscrew if needed.

the other bevel gear is the drive gear, the broken one is the actual reverser, no matter what direction your turning the one with the long shaft is engaged with the thread gears, as long as that one will engage the collar, it will turn the screw.
Slipping a gear in that's the same as the spindle will reverse it at 1:1 so the gear charts will read correctly, if you need the 'reverser' gear in the thread setting, double up one of the other gears.

Then use the box as just an 'on - off' switch untill you can find the correct gear.

Ken.

kendall
01-13-2007, 03:32 AM
name of the guy over on pm is Rex TX

a fairly recent posting from him regarding the shifter box is here:

http://www.practicalmachinist.com/ubb/ultimatebb.php/topic/25/1792.html


ken.

Paul_NJ
01-13-2007, 08:58 AM
Ken: Thanks for the clarification on how this lathe works and the ideas. I'm learning more each time, and saving postings like yours into my own "operators manual".

Mike: Thanks for the suggestions and particularly the encouragement.
but believe me, after you get the part to work you'll never look at a broken tool the same again. Yep, you'll start thinking junkyards are shopping centers!. I like that thought . . . I would really like to be able to accomplish that capability! I'll keep the gear and give it a try.

Al Messer
01-13-2007, 10:16 AM
Can't you use a file on it?

Paul_NJ
01-13-2007, 10:19 AM
Can't you use a file on it?


Not sure what you mean . . .

Al Messer
01-13-2007, 10:22 AM
Can't you modify the new gear with a file?

JCHannum
01-13-2007, 10:50 AM
The gear box is intended to change the direction of the leadscrew. The lathe is a change gear machine, and, depending on the gear train being used, the leadscrew will run in one direction or the other. That is why both gears are called reverse gears. It is not difficult to add another idler gear in the train to change direction if necessary, just a PITA, and it might cause interference with the gear guards. An idler gear of any tooth count will reverse the leadscrew direction without affecting the leadscrew ratio.

The feed is engaged with the lever on the front of the apron. The gear box is not to engage feeds, and should be shifted with the lathe turned off. The later lathes with the splined end like the new gear could be shifted while the lathe was running, but at the risk of wearing the splined ends.

The gear is diecast, and is easily worked with hand tools. It would not be difficult to carefully hacksaw and/or file the end to correspond to the shifter. It is not a high precision engagement, and as long as it moves reasonably freely, it will be functional.

J Tiers
01-13-2007, 11:01 AM
Actually, it doesn't look that easy to modify, because the shifter needs to fit into the interior of the gear, that half section fits in a cavity in the gear.

Working out a cavity like that is a bit more trouble than if it were just on the end of the gear.

Files, yes, but hacksaw? Where you gonna use a hacksaw? Maybe just a short piece of blade...... the half-round has to be cut in the inside of the gear.... It would be as easy to use a hoof knife on it.

Since the thing is, from what I read here, only needed for feeds away from the headstock, and since the feeds are via the leadscrew threading, it might be easier to simply avoid using the feeds in that direction.

It is the less used direction in general, not as useful for threading, which is the major 'feed" you need.

With a leadscrew feed setup, you get a lot of extra wear on teh leadscrew if you habitually use it for turning feed. Easier to hand feed, and you get a better feel for the machine, as well as changing gears a lot less. Save it for threading.

I'd put the gear in as a filler, if it fits, and go on with life, if that can be done.. leave it in normal feed all the time for now.

JCHannum
01-13-2007, 12:00 PM
Not having the gears in hand, it is difficult to tell the actual construction and depth of the "pocket". The teeth appear shorter on the lower side, leading me to think a portion of the offending material can be hacksawed off, reducing the amount of filing & fitting required.

The direction the leadscrew rotates is determined by the gear train, reverse being a relative term. Depending on the number of gears in the geartrain, that gear will feed in either direction. Introducing an idler in the gear train will produce the same direction change, eliminating the need for the gearbox.

Mike Burdick
01-13-2007, 01:08 PM
Guys,

All he needs to do is remake this part - it is very easy to to on his lathe because it doesn't depend on the broken part! Leave the new gear alone!

http://img.photobucket.com/albums/v491/myelsbeth/colar.jpg

Make this part on the lathe and cut keyway slot by using a boring bar and the carriage. Then remove and cut dogs in one side to fit the NEW gear and cut the other side half away like the original. Silver solder a new keyway in - just needs to be silver soldered on the ends so it doesn't fall out.

All this can be done on his lathe and the dogs can be cut using a hacksaw and a file. If he modifies the new gear its dogs may not have enough shear resistance and he will be right back where he started. Modifying only the shift collar and NOT the gear, in my opinion, is the best and easiest method to fix the given problem.

Wess
01-13-2007, 01:37 PM
I guess maybe I'm missing something here. Correct me if I'm wrong but to modify the new gear it seems to me you could put in on the rotary table and mill the half round pocket right into it. File the corners square and your done no?

kendall
01-13-2007, 01:45 PM
Guys,

All he needs to do is remake this part - it is very easy to to on his lathe because it doesn't depend on the broken part! Leave the new gear alone!



Actualy that's the best idea I'd say, I got stuck in the make new fit old mindset!

Only potential issue I see is that the leadscrew won't be 'indexed' as it is with the old one-way engagement, no serious problems, he'll just a need to leave the leadscrew engaged when threading as the thread indicator will not read the same after releasing and re-engaging it.

ken.

Mike Burdick
01-13-2007, 02:05 PM
....Only potential issue I see is that the leadscrew won't be 'indexed' as it is with the old one-way engagement, no serious problems, he'll just a need to leave the leadscrew engaged when threading as the thread indicator will not read the same after releasing and re-engaging it.

ken.
Ken, I don't think that will be a problem since this is only for forward and reversing the leadscrew. I don't think this has to be changed since all he has to do is release the halfnuts like most lathes normally do. But....if his lathe doesn't have halfnuts then you are correct. I'm not that familiar with that lathe's operation.

If the lathe functions like most lathes I don't think this modification will have any effect on how the lathe is operated and all of its original operational parameters should apply.

Another way he can make it, but I don't recommend this, is to chuck up the gear and machine all the dogs out. Then machine a round to fit in the part removed on the gear; cut in half and install with counter sunk screws. This part could be made from aluminum...if wanted. Very easy fix for a novice.

The important thing is that Paul already has all the tools necessary to make an acceptable fix.

kendall
01-13-2007, 03:54 PM
The important thing is that Paul already has all the tools necessary to make an acceptable fix.


That's the most important part all around!

could bore the center oversize, then shrink or epoxy a sleeve into it with the correct end on it, bypass the screw/tap biz all around.

Ken.

Rex
01-13-2007, 08:30 PM
Paul
Wonder if the later box would fit your lathe?
I have one that is complete except for the gear you just bought.

email sent, pics to follow.

Rex

J Tiers
01-14-2007, 01:46 AM
I agree that making the shifter collar would probably be better than modifying the gear.

Whenever you can make a new part to fit, as opposed to modifying a part you just bought, you have substantially less risk. You can make another part, and meanwhile you have all the old stuff.

if you modify the new gear, and mess it up, you are out the $$$

The problem is that making it right would involve a mill and dividing head.... which I suspect he does not have access to.

While it could be free-formed with files etc, it probably would have a risk of banging around on teh clutch teeth and messing up the new gear if not made right. The dividing head allows getting it just right, naturally.

So, leaving it for the moment would be fine, and has the least risk for him.

CCWKen
01-14-2007, 02:21 AM
Geez, you guys. That's what I said in the beginning. :rolleyes:

Mike Burdick
01-14-2007, 02:32 AM
Ken,

Sorry, you're right. When you said "Wow! I'd send it back. For $68 I'd cast a new gear myself." I stopped reading.:o Big mistake on my part... I should know better.

Mike

kendall
01-14-2007, 03:25 AM
Geez, you guys. That's what I said in the beginning. :rolleyes:


Uhhh, Well, we were ummm, Oh Yeah, we were just trying to give him the full overview so he'd appreciate your suggestion more!

Ken

J Tiers
01-14-2007, 11:12 AM
I think I'm in the clear.... I didn't actually say WHO I agreed with...... so I was just agreeing with CCWKEN..... :D