ARC-170's Craftsman 101.07403 lathe restoration thread

wa5cab said:
Unless it's actually painted steel plate, you need to double or triple the bench top thickness.
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A. It's a piece of 3/4" think MDF with 22 Ga (I think) steel.

B. I am going to use 5/16" bolts with fender washers underneath to attach the machine to the table. I'm also going to have a 22 Ga sheet metal tray to catch the oil.

C. The top is attached to the base with wood screws. This might be a weak point, now that I think about it. I could use bolts if that would be better.

D. It was originally attached to a cast iron stand with an approximately 1.5" thick wood top.
Would a thicker steel plate be for rigidity, weight, both, or something else?
 
MDF by itself is not very strong. It will tend to sag if the load is not directly over supports. The steel top will help but I would still be concerned about the combination sagging over time. Probably more on the headstock end.

For my bench, I used 3/4 by 2.75 inch hardwood bracing positioned under the lathe bed (front to back and side to side) and under the countershaft and motor. It is glued and screwed to the melamine-coated particle board top that came with my bench. I hope it is going to be sufficiently rigid.

Craig
 
22 gauge is sheet metal. You can easily bend it with your hands. I assume that it is on top of the MDF where it will give good service for keeping oil from soaking into the MDF. The original Atlas wood tops of their stands were 9" x 1-5/8" Maple. Today, you would use a 2 x 10 S4S. For something commercially available today, I would use two layers of 3/4" AC or AD plywood glued together with the "A" sides out. Drill all holes after the glue sets and then paint it before installing the sheet metal top.. If you put the sheet metal on top, paint the wood first. The hold-down bolts should be whatever fits the holes in the legs, which could be either 3/8" or 5/16"
 
WCraig said:
MDF by itself is not very strong. It will tend to sag if the load is not directly over supports. The steel top will help but I would still be concerned about the combination sagging over time. Probably more on the headstock end.

For my bench, I used 3/4 by 2.75 inch hardwood bracing positioned under the lathe bed (front to back and side to side) and under the countershaft and motor. It is glued and screwed to the melamine-coated particle board top that came with my bench. I hope it is going to be sufficiently rigid.

Craig
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True! After thinking about it and reading your post, I'm going to use a metal brace mounted under the table under the headstock.
 
wa5cab said:
22 gauge is sheet metal. You can easily bend it with your hands. I assume that it is on top of the MDF where it will give good service for keeping oil from soaking into the MDF. The original Atlas wood tops of their stands were 9" x 1-5/8" Maple. Today, you would use a 2 x 10 S4S. For something commercially available today, I would use two layers of 3/4" AC or AD plywood glued together with the "A" sides out. Drill all holes after the glue sets and then paint it before installing the sheet metal top.. If you put the sheet metal on top, paint the wood first. The hold-down bolts should be whatever fits the holes in the legs, which could be either 3/8" or 5/16"
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I ran my existing setup by the machine shop teacher where I work and he thought I'd be okay as long as I wasn't taking heavy cuts. He told me to try it and see how much vibration and shaking I get. Easy for him to say! Ha!

The sheet metal is for oil, not support. I like the idea of going with 2x10's, but plywood might be better. I'm thinking maybe adding some sort of "L" channel under the table for support might work. I might have to re-think this. I'll try and post a picture of what I'm thinking.
 
I'm not familiar with MDF but from the comment above, think that it may be like particle board. Which is not particularly stiff. If that's the case, I would suggest substituting plywood glued together.
 
I am wondering why not get some maple. You've got a good lathe with a lot of work in it, reconsider the mdf! No expert here but when I put my old atlas on a workbench made of 2x8s covered in stainless and screwed to the garage wall I could clearly see deflection in a machinist level just by leaning on the bench. This is when I was leveling the lathe. How much this really matters I don't know. But as these are fairly light duty machines good to strive for all the rigidity you can get. I have very little real world experience yet everything I've read and heard suggests going for the stiffest (and heaviest) base you can get.

I really like this thread- thanks for posting

Tim
 
I have some oak boards, maybe I'll use those. I also have a steel "L" channel that's about 1/8" thick that should add some stiffness. The plan is to mount it front to back under the lathe and bolt it, the table and lathe all together. I also plan to screw it into the table at the ends, as there is a lip on the table sheet metal. I'll do this no matter what material I end up using for the top.

I appreciate all the comments about using a stiffer material; it's made me reconsider. Stay tuned!

My question is really about WHERE on the table to mount the lathe, meaning front to back and side to side. If you look at the pictures, it's not in the center; is this a problem?
 
Most of the weight is in the area of the headstock, motor and countershaft. Ideally you want the legs under the centre of that mass. Since I couldn't do that, I put most of the underside bracing under those areas so the load was carried over to the legs at the corners. It is only 8 months old but this seems to be working for me.

Craig
 
Mount the lathe near the front according to various drawings. And let the rear fall where it may. This would have the center of the front holes around 1-1/8" back from the front edge. Any drip pan (whether fixed or removable) should hang out past the front edge about another inch. So that anything that misses the pan will go onto the floor, not the bench top.
 
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