Two Collar test

I was doing a two collar test on my 10K with my two old Buck chucks and i have an issue with the pattern at the 10" from the chuck. The dimensions are with in .0002 and alinement is with in .0004 vertical and horizontal, but there is a pattern formed at the 10" collar. I did both chucks same pattern, i tried different inserts both HSS. and carbide. Up close to the chuck the collar looks like a mirror. Tried different speeds, same results……… jim

10" is too far out.

we had this discussion in another part of the forum and it was a mess.

a 1.5-2" bar of aluminum or easy cutting steel like 12l14 with no more than 3x the diameter sticking out is what you need.

I guess the old lathe is smarter than me, i did a 6" one and it was all right. i was working on an alignment issue. I guess the 50+ year old lathe is as good as new and the 71 year old operator is the weak link……. Thanks, jim

Are you doing the two collar test with the work held between centers? If not, I suspect that vibration is causing your pattern.

As iwananew10K says, use a shorter peice, large diameter for stiffness and have it supported by the chuck. That will give you details on things lie spindle alignment.

The 2-collar test (with the piece between centers) is good for tailstock alignment and bed twist issues.

Steve

Man, that method works great too. I used a 1.250" piece 5" out from the chuck and it was off .004". Shimmed the font of the bed .064" and she cuts .000" across that 5" piece. Yes, it was starting to chatter a little at the outside, but I wasn't worried about finish, just measurement for that piece.
Haven't tried it for the tail stock alignment. Been using an indicator for that, so far.

Chris

once you have your bearings adjusted,done your collar test and got it turning true...

for the tailstock I very much recommend Richards method, as it takes the guesswork out and you can find out what your tailstock is really doing.

Just chuck up a piece of scrap with a couple inches sticking out and turn it to the EXACT diameter of the tailstock quill.
Then bring your tailstock up quill extended to the turned piece, lock it down to the bed and lightly lock the quill.
Use an indicator fixed to the carriage and indicate over the top and sides of the turned piece and quill.

Prepare to cuss as you find your tailstock quill is nowhere near straight, likely it will be low,pointing down and away.

ponder the situation and figure how you can improve it...really only one way.

Get yourself a 12x18 surface plate,a few appropriate measuring tools, a hand scraper, and a cheap angle plate.
make cheap angle plate flat and square.
Then go for 20 ppi.
Get a chunk of durabar
Make a 45 degree straight edge because after you rescrape your tailstock your gonna want to do your compound and cross slide.

iwananew10K said:

Make a 45 degree straight edge because after you rescrape your tailstock your gonna want to do your compound and cross slide.

Click to expand...

If you give a mouse a scraper....

SteveM said:

Are you doing the two collar test with the work held between centers? If not, I suspect that vibration is causing your pattern.

As iwananew10K says, use a shorter peice, large diameter for stiffness and have it supported by the chuck. That will give you details on things lie spindle alignment.

The 2-collar test (with the piece between centers) is good for tailstock alignment and bed twist issues.

Steve

Click to expand...

It was only held by the chuck each time i tried it, a shorter piece about 6" was perfect…….. jim

SteveM said:

If you give a mouse a scraper....

Click to expand...

??? i give up,what would happen?

You don't have small children, do you?

http://www.amazon.com/If-You-Give-M...&sr=1-1&keywords=if+you+give+a+mouse+a+cookie

Steve

i do, but remember it as if you give a pig...LOL