ML7 cross slide question

[AndyNC]

Hi,

I'm trying to work out what units the cross slide micrometer wheel is in.

It is has 100 marks but when I hold a rule against it and turn it once it seems to move 2mm. Trying this in English did not give meaningful results.

Is it possible that each division is 0.02mm ie 8 thou?

Cheers

Andy

 

[Wildman]

why not just take a one division cut and measure the difference as its is probably a multistart leadscrew

 

[dickm]

Wel...l....l.....l. The obvious answer is that you have a metric ML7, but post your question on the Myford lathes forum on Yahoo, and the experts will be buzzing around you in seconds

 

[AndyNC]

I did assume is was metric but I thought the division would have some direct relationship with movement instead of a ratio.
Done some test cuts but it doesn't stack up.

I did 3 separate 1 divisions cuts and got an average of 0.051/div on the diameter.
so 1 div is 0.025.
But if 100 div ( 1 turn) is 2mm that's 0.02/div.

This could be because of wear on the thread plus error in readings. I'll take a deeper cut and recheck.

Cheers


Andy

 

[jasonB]

Its most likely a 10tpi leadscrew so one turn is 0.100" or 2.54mm, one div 0.001" or 0.0254mm which gives 0.0508mm off dia which is basically your 0.051mm average

 

[AndyNC]

Hi Jason,

That's a good correlation.

I'll do a few more test and see if 10tpi stacks up.
I may do them this evening but if I can't I'm off to sunny Crete for 10days on Tuesday so it'll have to wait until I'm back.

Cheers

Andy

 

[AndyNC]

Hi,

Had a few more minutes than expected.

It is definitely 1 div per thou.
I tried it against a rule and it correlates to 1 turn per 0.1". Also did some trial cuts.
Don't know how I missed that the first time I tried it. Must be the drugs or lack of.

Sunny Crete tomorrow. Yipee

Cheers

Andy