It makes you appreciate their skill (machine tool building)

[.RC.]

I have been working on the tailstock of my lathe...It would never clamp firmly and when clamped it would move slightly like it was not sitting on the ways correctly....Upon blueing it up it was only touching in four small places....

I soon fixed that up with a bit of careful scraping....Next was the fitting of the upper and lower parts..I found that these were not fitted at all and were in fact rocking against one another...I scraped one flat against a surface plate and then fitted the other one against it...

It has remedied the problem but what I found interesting was the amount of precision work required to do a good job and that it is very time consuming....You may only remove super small amounts of metal but the removal of that metal can shift alignments elsewhere that mean instead of it being a machine accurate to 0.02mm it instead blows out the accuracy to 0.05 (0.002") or worse and when it comes down to the likes of bearing fits 0.05mm is just too large of an unknown to work with.

It really makes you appreciate the amount of skill needed to make super accurate machines, and also why something like a HLV costs $50 000..

[Carld]

Hi ringer, I read your post on PM also. The good part of making everything fit better is if it is just out a couple of thousandths on the tailstock your ok. Most work with the tailstock will have runout anyway. As you said, it takes an expensive machine to hold tight tolerances. A lot of "machinists" fail to realize that and try for tolerances their machine can't do.

[daryl bane]

I like to see HSMs pulling out the scrapers to fix their iron, old or not. Seems there is a lot of emphasis on pretty paintjobs, but not much discussion on really restoring accuracy. It is certainly easier to paint than scrape correctly.

[Oldbrock]

Nice fix, now you have to check if your tailstock is now a few thou low with an indicator or co ax indicator from the headstock. You may have to shim it up to have it on center. Peter

[Teenage_Machinist]

Wow. I finally made a scraper. Better get some prussian blue and check my tailstock.



Not to hijack, but I sucsessfully brazed carbide onto an old file with a mapp torch and Home Despot white flux coat bronze brazing rods..



My chineese lathe has scraped tailstock, but I had better check it.

[Fasttrack]

Yep - there's no substitute for quality! And, if you want quality, you have to pay for it

Working on my Pacemakers really made me appreciate all of the effort and skill that went into designing and building them. I had gotten used to import machines and thought a Cinci traytop was one hell of a lathe. Then I got spoiled. Really amazing what the were able to do back then.

[.RC.]

Hi ringer, I read your post on PM also.

It was actually supposed to be posted here but I did not realise I was on the wrong forum till after I posted it....A case of having too many windows open...

I took a test cut with the tailstock....I only have a chinese mic so the results are probably not reliable but I appeared to have got a 0.002mm taper over four inches..

Good enough for me..