[Taflin]

i beg to differ

PMM-G - Brown & Sharpe

First of all that is a Leitz. And I still bet the uncertainty is worse that 1.7ect...

[thefu]

I stand corrected. His machine has the same uncertainty as yours as verified by a phone call. that being said my setup is accurate within .0004 over a 10 foot span

[Taflin]

I stand corrected. His machine has the same uncertainty as yours as verified by a phone call. that being said my setup is accurate within .0004 over a 10 foot span

That machine is a beast, I am seriously jealous you have access to such a piece of machinery.

Best of luck!

[thefu]

I was also wrong on the machine sadly. its the lmm-f. I dont get to use it personally but i do have unlimited access to it. I simply do not have the time to learn how to use it or the time to head over to his shop much.

http://www.leitz-metrology.com/leitz...201016_694.htm

its an amazing piece of equipment though, he uses it to measure very large mirrors for the solar industry after they are certified by sandia national laboratory.

[Taflin]

I was also wrong on the machine sadly. its the lmm-f. I dont get to use it personally but i do have unlimited access to it. I simply do not have the time to learn how to use it or the time to head over to his shop much.

http://www.leitz-metrology.com/leitz...201016_694.htm

its an amazing piece of equipment though, he uses it to measure very large mirrors for the solar industry after they are certified by sandia national laboratory.

I think the F is even more accurate than the G. They unfortunately do not advertise the rated accuracy of the G. Just slightly smaller travels.

CMM programming is a ***** if you can get someone to do it for you all the better, the information you get from it is what counts.

[thefu]

F is MPEE = from 1.7 + L/400
G is MPEE = 2,4 + L/400 on the smallest comparable

[harryn]

Our rack is machined and results in AGMA Class 8 Specifications. While there is no current AGMA standard for racks, we refer to the pinion specs for acceptable tolerance. For 20DP-20PA, Tooth to tooth composite tolerance is within .001" with a total composite tolerance of .0019". Keep in mind, this is the gear rack ONLY and does not take into consideration any other factors such as pinion precision, mounting, etc.

If you need more precision, then your next option is ground rack.

Diane

Hi Diane,

If a person is interested in even tighter results, what is reasonable to expect from your ground rack offerings. Example, 14.5 degree PA, 16 DP combined with a 1 inch pinion.

If you feel another rack style is more representative of your capability, then please comment on that as well.

Other than an increase in price for the extra work, is there any reason not to use a ground rack ?

BTW, I have read that this PA is better for noise and meshing for these smaller pinions, but less strong. Does that make sense based on your experience ?

Thank you,

Harry

[hanermo]

This sounds vastly too high "0.003" every 0.1".
Thats 0.08 mm per 2.5 mm.

I bet the error is not in the rack.

All errors measured I have seen online have been more or less lineal. Ie a screw will not all the error in one spot, nor will it jump instantly from one point to the other.
I suspect your mechanicals.