Rigidity in an Atlas 10F lathe -HELP-

[Moderatemixed]

The plinth is basically a big block of steel, same height as your compound but bolted to the cross slide. Stefan G, Rob Renzetti both have YT videos on how they made theirs.
Here is mine on a 10x22. Not quite wide enough, will be widening the base soon. In your case a tall piece of round steel the diameter of the base will be all you can do.
No doubt somone will pipe up and say 'but then you can't thread' which might be true from the usual North American approach but in EU it is normal to plunge straight in for fine threads (which is pretty much anything less than 13tpi) so not really an issue.

I still think you should just bolt the lathe to a 7 or in wide u channel

Thanks G. I really appreciate the further insight. I think I might look at what Pierre has done with his vs the metal u channel for the time being. I have an idea and will discuss tomorrow. Thanks as always for the insight....

Cheers, Big B.

Derek


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[gerritv]

I have a Plan D as well, with free metal for you to use to do it.

 

[Moderatemixed]

I have a Plan D as well, with free metal for you to use to do it.

Best kind! Talk to you tomorrow about 2?


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[westerner]

One other item to check is if the bearing plates on the saddle were reshimed after the bed was ground. Regrinding the bed will change the clearance between the under side of the bed and the bearing plates.

I did a 'poor man's' scrape job on my old Craftsman. I had to change gib shims to make up for the material removed. The local tool guy had shim stock that worked out. I have extra, if you need some skinny stuff.

 

[Moderatemixed]

Nice job on the lathe rebuild. It sure is pretty. At risk of sounding like a broken record ,loose the carbide and grind some high speed steel. There is an excellent write up by one of the members here on how to grind a lathe tool bit. With a honed edge on hss you will be amazed at how much better the atlas will perform. One other item to check is if the bearing plates on the saddle were reshimed after the bed was ground. Regrinding the bed will change the clearance between the under side of the bed and the bearing plates. Also the saddle may need to be scraped in on the reground bed. Do the simplest thing first and try a sharp high speed tool bit. Good luck. The members around here are great at helping out. Let us know how it turns out.

I hadn’t thought about the shims on the underside of the saddle but there doesn’t seem to be any up and down play. I will check it out a bit more closely tomorrow. Great points all around and yes, I am going to switch to the HSS. I have a sharpening system (Toycen Journeyman with the Tradesman Machinist attachment). Essentially it will sharpen anything from end mills to drill bits and everything in between. It uses a 6 inch CBN wheel for grinding and sharpening lathe tools (contrary to what is generally considered normal) at low speed, but I will review the tool geometry before jumping in. Thanks for the suggestions and advice.

Cheers,

Derek


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[Moderatemixed]

I did a 'poor man's' scrape job on my old Craftsman. I had to change gib shims to make up for the material removed. The local tool guy had shim stock that worked out. I have extra, if you need some skinny stuff.

Thanks for the offer! I have a box of Starrett shim stock that I picked up for a song; all of it new in sleeves and progressive sizes from .001 to .030, in .001 increments so I should be ok. I will let you know however if I get stuck. Thanks again.

Cheers

Derek


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[pdentrem]

The alum plates had only 3 points of contact per each. 4 points of contact would be difficult to regulate. The hold down bolts passed through the plates, and the table top. The plates were drilled and threaded for the bolts which acted like adjusters to level and support the lathe. Was not my design, I bought the whole set up from a retired machinist. He had upgraded to a Harrison lathe.

 

[westerner]

Oh, you have got what you need. Nice score. Way oil will help you to feel exactly how tight you are. Have fun. You will sort it out. These machines are not known for their rigidity, but they can be useful. I surely enjoyed my time with one, for it definitely made me a better machinist.

 

[shadetreedad]

Another likely thing that may be your issue is the feed rate. I'm pretty sure the slowest feed rate on your quick change gearbox (without a compound gear) is .0042”. this is really quite fast. Try installing a compound gear setup & slowing your rate of feed down to .002” or less. I have a Pick-O-Matic drive box and can select only 3 speeds. My fastest of the 3 is .0042”. And that is almost too fast for anything but the lightest of cuts in aluminum. The speed I use the most is 1/2 of that .0021". And for finish cuts 1/2 of that .0010". Very slow.
Mike

 

[Moderatemixed]

Another likely thing that may be your issue is the feed rate. I'm pretty sure the slowest feed rate on your quick change gearbox (without a compound gear) is .0042”. this is really quite fast. Try installing a compound gear setup & slowing your rate of feed down to .002” or less. I have a Pick-O-Matic drive box and can select only 3 speeds. My fastest of the 3 is .0042”. And that is almost too fast for anything but the lightest of cuts in aluminum. The speed I use the most is 1/2 of that .0021". And for finish cuts 1/2 of that .0010". Very slow.
Mike

I did a modification that I found online that “halves” the feeds. Then you just move the threads per inch “up a line” on the QCGB so my feed is .0021 per rotation. A very good point though. I will follow each of the points that everyone has made (I’ve made a checklist) and will report back next week.

Cheers.

Derek.


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