Anyone know Atlas 12” Lathes?

[WhoWhatNow]

I just picked up an Atlas 3980 12” metal lathe. It is the bench mount model with the quick change gear box. I need to either repair or replace the quadrant bracket (part #18 in the pic below). This is a bracket holds the gears that connect the spindle gears to the gearbox gears. It is broken in at least 3 places. My questions are:

1) does anyone know if this bracket is cast iron, hardened steel or the dreaded Zamak?
2) Does anyone know if the bracket from the 10” lathes will fit the 12”? There are several of the # 10-25 brackets available on eBay but I am not sure they will work.

Other than this part everything on the lathe appears to be in good shape.

The 12" part:


The 10" part:


Actual part:

 

[rsanter]

Fairly,sure,it's cast iron

Look,up the part numbers for both to verify, but I think they are the same

Bob

 

[Zrexxer]

It was cast iron on my 6", can't imagine it would be anything else on the 10 and 12's.

 

[steel 35]

My parts list's show your #18 for a quick change 12" is part# L6-1007 (Change Gear Quadrant) and if you look closely at the two parts no there not the same.

 

[tdkkart]

It'll be cast iron, and there is a specific part for quick change machines.

 

[WhoWhatNow]

Thanks for the replies. Good to hear it is cast iron so there is at least some hope of welding it up. I saw the part numbers and picture were different for the 12 and 10" models but I think I was hoping the critical dimensions/geometry was the same for the different parts.
Does anyone know how much stress is placed on the part. Could a replacement be made out of mild steel? Heat treated maybe?

Ereplacementparts.com shows the part # L6-1007 as available but at a price of $300. Considering I only payed $400 for the whole lathe I don't think that is an option even if the part is available.

 

[A_Pmech]

Mild steel would work fine for the banjo bracket.

 

[WhoWhatNow]

Mild steel would work fine for the banjo bracket.

Thanks you! I was worried I was going to have to build a furnace and cast a new one. Now I just need to pretend like I know how to use my Bridgeport.

 

[BillK]

I think you can still buy the parts from Clausing.

 

[A_Pmech]

Thanks you! I was worried I was going to have to build a furnace and cast a new one. Now I just need to pretend like I know how to use my Bridgeport.

It'll be a good practice project for you.

Cut out the blank from a piece of steel flat. Weld in the pivot point and bore it to size. Then, locate the slots and machine them. Remember that an endmill always cuts oversize in the real world, so use one smaller than your final slot width and make a finish cut on both sides of the slot.

 

[Boomer343]

Many moons ago I had a broken one and while waiting for parts took a chance and brazed it myself. I never did replace it when the new part showed up. I had 3 Atlas lathes being used by high school students and that was the only gear train part that ever broke. Good machines.

 

[Riverside]

You will find lots of information about your lathe on the Atlas/Craftsman Yahoo group:

https://groups.yahoo.com/neo/groups/atlas_craftsman/info

In some cases, Clausing sells parts for much less than people are asking on ebay (and in many cases, they no longer have the parts).

 

[tdkkart]

Typically there's a ton of Atlas parts on Ebay, if the one you need isn't there today, it'll probably show up within a couple weeks.

 

[WhoWhatNow]

It'll be a good practice project for you.



Cut out the blank from a piece of steel flat. Weld in the pivot point and bore it to size. Then, locate the slots and machine them. Remember that an endmill always cuts oversize in the real world, so use one smaller than your final slot width and make a finish cut on both sides of the slot.

That's what I was thinking. When you say make a finish cut on both sides do you mean cut halfway through the plate on one side then flip it over and cut the rest of the way through? Or cut completely through on one side then take a light pass from the other?

Many moons ago I had a broken one and while waiting for parts took a chance and brazed it myself. I never did replace it when the new part showed up. I had 3 Atlas lathes being used by high school students and that was the only gear train part that ever broke. Good machines.

Good to hear they are sturdy machines. I went back and forth a bit about this machine in part because of the Zamack gears and flat ways but I think for my limited hobby use it will be more than adequate. It was being used in a small pro shop before I pulled it home over the weekend.

You will find lots of information about your lathe on the Atlas/Craftsman Yahoo group:

https://groups.yahoo.com/neo/groups/atlas_craftsman/info

In some cases, Clausing sells parts for much less than people are asking on ebay (and in many cases, they no longer have the parts).

Thanks for the link to the yahoo group. I will check it out. I think I will call Clausing today to see how much they want for the part. Ereplacementparts.com has it listed for ~$300.

Typically there's a ton of Atlas parts on Ebay, if the one you need isn't there today, it'll probably show up within a couple weeks.

Searches already set up!

 

[Matt Irvine]

That's what I was thinking. When you say make a finish cut on both sides do you mean cut halfway through the plate on one side then flip it over and cut the rest of the way through? Or cut completely through on one side then take a light pass from the other?

I assume what he means is, using a slot drill with a smaller diameter than the width of your slot, centre the spindle over your slot and cut right through, take two even passes on each side of the slot to bring it to size, and true it up. That would be how I would do it anyway.

 

[A_Pmech]

That's what I was thinking. When you say make a finish cut on both sides do you mean cut halfway through the plate on one side then flip it over and cut the rest of the way through? Or cut completely through on one side then take a light pass from the other?

Plunge completely though the part with an endmill diameter smaller than the slot width. Then, make full depth finish pass(s) on either side of the slot to size and locate it.

 

[POS Racing]

This guy helped my get my Craftsman Industrial AKA Atlas late up and running - http://www.mymachineshop.net/

 

[WhoWhatNow]

Thanks for the tips guys. I haven’t had time to tear into it yet. I think I want to make a part or two before I tear it down. Once I get play around with it a little and see what else it needs I think I will make a new banjo bracket as suggested here.

Another question I have is about replacing the motor with a VFD and 3 ph motor. I would like to do this swap for two reasons: the ease of changing speeds and to convert the lathe to an underdrive to better fit into my miniscule shop. This type of Atlas lathe originally came either as a benchtop unit with the motor hanging off the back, or and underdrive model. The underdrive model had a different pulley on the spindle and two sets of drive pulleys plus the motor under the headstock. If I add a 3 ph motor and VFD with sensorless vector drive do I need to also recreate the additional pulley setup or can I simply have the motor driving the spindle? Do the additional pulleys add a torque advantage over just the motor? Also, what speed motor should I get? The lathe currently has a replacement motor Baldor 1 hp 1 ph motor spinning at 1750rpm. Do I simply calculate the top speed I want and put the correct size pulley on the motor? The original top speed of the lathe is listed at ~2200rpm.

 

[Miket]

A lot of people will chuck the motor and actually go to a treadmill motor and speed controller, then mount up an rpm sensor to control speed.

A buddy of mine did it to his southbend and loves it. Something I am going to do to mine as well.

I did it for a bandsaw and it works great for metal cutting converted a wood to variable speed for metal.

Same theory applies. Find a cheap treadmill or free on craigslist.

Stuff all over internet about how to convert it.