Need help finding the right micrometer

I have a measurment I need to make and we need to use the data for SPC. the Mic I had in mind was a Mitutoyo 345-351, I called and even asked the Tech support guy at Mitutoyo if this would work for my application, He told me that it had 2.5mm round anvils just like the 345-350 which is the 0-1" of the same style. The Mitutoyo information page on their website also shows a round anvil.

I ordered it and it came in, well it was not what I expected. It had caliper style anvils with a radius on them, but the radius is not small enough even if I grind a chamfer on the sides of the anvils, it will not measure the slot in the part I need to measure.

I am trying to check a slot that is 47.10mm long and 3.5mm wide with a 1.75mm radius on the ends.

If anyone knows of a mic or off the shelf gauge that will work for this that has spc capability, Please let me know.

TIA
Snocat_trf

Try These

What about a phase II 103-130 0~1" electronic blade Mic...resolution listed at 0.0001"/0.001mm. or Mitutoyo 422-421 listed as spc output w/ 0.00005" resolution..and whop'in big price. blades at .030" should be thin enough to btm out in the groove?

this is an internal slot i am trying to measure.

We'll ya never said that....

Probably a feature better checked pass/fail with a go/no gage. You can't accumulate dimensional data for analysis but generally what do you care so long as the part fits?

If the customer insists of hard dimensional data, you can make a tube and rod coaxial thingy with a LVDT (?) on one end and something like a steep angle adjustable parallel on the other. Use a pistol grip or a pushbutton to actuate the parallel thingy so it wedges tight in the slot so the LDVT can determine the displacement from nominal. Calibrate it from a gage for repeat zero, I think there's a standard chip for converting analog LVDT signal to SPC.

I realise this is but a gloss of the actual concept but if you need dimensional data from hard to reach features you quite often have to make something. Yes it's expensive and a hassle. That's why pass/fail functional gaging is still with us.

I already have the pass/fail go/nogo gauge, I need to collect data and I was hoping a simple off the shelf mic would get the job done.

Dial Indicator Groove Gage

How about something like this:



http://catalog.starrett.com/catalog/catalog/groupf.asp?groupid=585

Put your own tips on it and an SPC output indicator.

Cal