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Scraping lathe ways /preservation geometry.

alien97pl

Plastic
Joined
May 18, 2019
Hello.First thread in this forum.I have old Polish bench lathe with well worn bed.Grinding is horrible expensive in my region.I have been scraping few years ago so i thought thats good idea to do it by hand.First of all i need to ask you how to scrape to preserve geometry of this bed.
My first idea is to scrape prism nr.5 and flat surface nr.6 belonging to tail stock.After that install on the tail stock plate mini handle electric drill with cutter and mill 1,3,4,2. That's only idea but that will be pretty dificult to make is stable.
I have 2x 1 meter surface palte,dial indicator,many micrometers,but not enough knowledge how to scrape and not make the bed scrap :)

I hope somebody will reply ma post cause long time no one is able to help me.
Greetings from Poland
Przemek



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It looks like the lathe is not installed or level so that will be the first thing to do

You need to map out the wear

A kingway type tool is what I would want

Good luck
 
You are going to need a long straight edge of some sort, (cast iron or granite) You can make one using the surface plate as a reference from some continuously cast iron, an old lathe you cut up or other things of the sort if you can't find one locally. You will also need a precision level.

Given that you have a large surface plate you should scrape the bottom of the lathe bed where it touches the plate and sit the whole bed on the plate and use that to maintain horizontal alignment of the flats etc by checking with an indicator. For the other orientation perhaps there is also an unwarn surface that can be used to establish alignment along the axis of the bed, or just scrape the front or back edge and base everything off of that. There will be areas at either ends that are unworn which are helpful for alignment. Ultimately so long as everything is parallel the exact angles of the V's don't matter as you will need to scrape match the tail stock and saddle to the bed.

although milling the ways is appealing it might be more trouble than it is worth depending on how much material you need to remove. The tailstock ways aren't a good way to do that as it doesn't have gibs to allow it to slide while being held down, but you could scrape two surface flat and parallel then bolt on some linear rails (Hiwin type) and use those to move a milling head along but that sounds like a pain unless you need to remove a huge amount of material and those rails aren't super cheap. what is the total bed length?

this thread could be helpful
https://www.practicalmachinist.com/...tion/stanko-semi-overhaul-348930/#post3319629

L
 








 
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