Repairing Atlas 10" lathe

[bogstandard]

Hi Ross,

If it was feasible, having a swap over babbit head would be the ideal solution, then you could use whichever one was perfect for the job.

On your first pic, the one with the drill, if you go to the top right, you will see the vertical and horizontal joint lines between the apron and saddle. If you slacken off the apron bolts on the top, you should be able to insert a shim at either end of the vertical joint. I would use a couple of coke can shims, and by doing that, the apron should be moved away from the rack.

If that didn't work, as far as I can remember, the troublesome gear is just held on the shaft by rough peening over. By the marks shown, it looks like the gear isn't square on to the shaft. There would be no harm done if you just took a file to the gear and reduced the high spot until you got no fouling. Maybe try this before shimming.

not pretty but hopfully functional

Ross, paint doesn't cut metal, so just being a bit scruffy means nothing, you can slap a bit of paint on anytime.

John

[Ross77]

Thanks John

my descriptive skills seem to be lacking.......it isn't the drive cog and the rack that are binding but the face of the cog and the bed.

If it is the rough peening then how much can I remove before it becomes weak?

thanks for the encouragement for less than beautiful machine. personally I agree with you but there is a trend for perfect shiny machinery.......

[irving2008]

What John was suggesting was shimming the vertical split between the outer and inner parts of the apron (see arrow in pic). this would have the effect of moving the gear out away from the bed.

However, judging by the position of the marks on the bed the binding isnt the gear itself but the end of the shaft on which it is located. I'd have thought taking a light grind off the end of the shaft/gear face (a few thou) would resolve that without compromising the peening/fitting...

[Ross77]

Thanks irving and John.

Yes the bind is the end of the shaft but the apron is non movable

[bogstandard]

Ross,

I'm sorry, I should have said that I realised it wasn't a gear/rack problem.

Irving has said it all.

but the apron is non movable

Almost everything on that lathe is moveable, you just need to know how to move it.

The peening, as far as I can remember was a real rough job, and I think I ground down mine to be level with the face of the gear, then centre popped around the edges of the shaft joint to keep the gear in place.

Things like this really are a 'suck it and see' exercise, and you just do what is required to get the machine running correctly. The clones were never meant to be a super high accuracy machine, but with a little work, they can easily be turned into one.

John

[bogstandard]

I suppose I had better qualify my statement in the last post where I stated that everything is moveable.

My Atlas didn't have a dowel pinned apron, but from your comment, I suspect yours is.

If that is the case, you shim up in a slightly different way to achieve the very tiny movement that is required.

Slacken off the top apron bolts to give you a tiny gap on the horizontal joint. Then you insert a narrow shim into either end of the joint, but very close to the vertical join. When you retighten the joint, you will find the apron has kicked out slightly, maybe with just one coke can shim, enough to cure your interferrance problem.
This will move the apron out by a tiny amount, but I wouldn't go more than a couple of shims as you will be putting a lot of stress on the dowel pins and castings. If you can't get the required clearance by shimming, remove the shims, then resort to grinding or filing a little off the peened area.

John

[irving2008]

John,

Without cutting up a coke can to measure (surprisingly I dont have one to hand) how thick is a 'coke can shim'?

[bogstandard]

Irving,

We only have Pepsi Max in our house (no sugar content), and they usually measure up at between 0.0025" to 0.003" (somewhere around 0.06mm).

Being made of soft ali, if used in between iron or steel parts, they should compress down to about 0.002" (0.05mm) with a little excess pressure.

It really is a very cheap and acceptable material for shimming. Proper stainless shim material can be a little on the expensive side, a small range pack of 6"x4" sheets can easily cost £20

I also use a fair amount of it as protectors between the part and the chuck jaws when turning, it prevents a lot of the bruising you normally get on fine finished surfaces.

So stuff recycling bins, recycle the cans yourself.


John

[irving2008]

Ah... dont touch the stuff myself, but my wife is addicted to Coke Zero (if a couple of cans a day is an addiction), but as I put the recycling out yesterday there are none to cut up... I'll acquire a couple in the next day or two...

[Ross77]

My Atlas didn't have a dowel pinned apron, but from your comment, I suspect yours is.

yes the apron is dowel pined but I suppose I could remove them? Haven't had chance to look at it today but I think you have covered all the options cheers.

I like the idea of using cans as shims and workpeice protectors, I do have some proper shim steel but I didn't buy it and if its as expensive as you say then when it runs out I'll be using the cans.

I don't drink coke or fizzy drinks much but I'm rather partial to the alcoholic variety and they are bigger cans too.

Just need a rainy evening to get in the workshop.