Help with Mitutoyo micrometer

[c.k.93]

I getting ready to turn some brass with short necks. My Mitutoyo micrometer model 115-313 spindle is too wide to get consistent readings. Do you guys know of anyone that sharpens these spindles? A name, phone, or email address would be great. Thanks for your help!!!

c.k.93

 

[mr45man]

I would get a quality callaper that measures to .0005 or better.
John H.

 

[Eddie Harren]

I would consult the Mitutoyo catalog or, website.
I would never trust a caliper to give me good enough readings for neck thickness.
Caliper: Quick & close but not precise.

 

[tenring]

I had my smith turn mine down to a semi point. The end of the spindle is about .020" wide. Works fine on short necks, i.e., 223, etc.

 

[fdshuster]

c.k.93: I made some inquiries about the same topic, since with the standard "flat" contact surface it's impossible to get close to the shoulder. With a short necked case like a 223, you're only able to measure the wall thickness close to the mouth of the case. Anyway, I was told by several professional machinests that most quality micrometers (like our Mitutoyos) have a carbide insert that is press fitted into the stem: try to turn it to a "sharper" shape and the insert will seperate from the main part of the stem, damaging the micrometer.

tenring: Did your 'smith have an issue with the carbide insert or did the modification go smoothly?

 

[jlow]

Not sure I understand this comment “My Mitutoyo micrometer model 115-313 spindle is too wide to get consistent readings”.

Are you saying you cannot get the ball inside the neck? Or you can get it into the neck but still cannot get a reading – what caliber cases are you talking about? Also not clear to me if it is the ball or the flat part that is giving you trouble and where in the neck are you trying to measure wall thickness.

Not trying to give you a hard time but usually the more detailed the question, the faster you get the right answer.

 

[dblinden]

http://www.kmshooting.com/catalog/miscellaneous-items/mitutoyo-wall-thickness-micrometer_60-degree-modification.html

I have this and it was worth the investment. Very easy to use and get repeatable results. They cut a 60 degree angle on the spindle top. Maybe they will cut yours for a much smaller fee.

Dennis L

 

[fdshuster]

Dennis L: Yes, I saw that advertisement & picture previousely, but did not realize they might modify an existing flat stem to the 60 degree. Just sent them an e-mail for info, and will post their response. Thanks for that. fds

 

[c.k.93]

Thanks dblinden, that's the link I was looking for. Thanks for the other responses. I'll try to attach their picture from K & M. Here's their description: Mitutoyo Wall Thickness Micrometer with 60 Degree Modification. Accurately measure case neck thickness to 0.0001" resolution (one ten thousand). This is a vital tool when turning necks or sorting brass. Our 60 degree modification allows you to take measurements close to the shoulder.

c.k.93

 

[dblinden]

I know most people prefer electronic/digital measurement tools, but I prefer this. It is fast, has a precise feel, and a good visual on the scale. I purchased an inexpensive micrometer stand on ebay or Amazon and that provides hands-free setup on the desk. It is adjustable for setting the viewing angle.

Dennis L

 

[aj300mag]

Anyway, I was told by several professional machinests that most quality micrometers (like our Mitutoyos) have a carbide insert that is press fitted into the stem: try to turn it to a "sharper" shape and the insert will seperate from the main part of the stem, damaging the micrometer.

You don't "turn" the spindle down to a point. I use a diamond wheel in a cutter grinder to rework the spindle. And I am a professional machinist.

 

[tenring]

[q
uote author=fdshuster link=topic=3811399.msg36205450#msg36205450 date=1365021959]
c.k.93: tenring: Did your 'smith have an issue with the carbide insert or did the modification go smoothly?
[/quote]


He did not say there were any issues. I did not ask his method for turning it down. Kenny Markle used to do this for BR guys all the time, and I never heard of any problems with it.

 

[fdshuster]

aj300mag: I never suggested that it be turned down to a "point". Only as pictured with the Mitutoyo as advertised by KM.
tenring: They were not comfortable doing the work, there seemed to be a general consensus that the micrometer would be damaged, so nothing has been done.

Sent KM the e-mail, still waiting for a response.

 

[aj300mag]

I can't visualize how they figure they'd damage the mike. You take the spindle apart, slide it into a collet being careful that you don't damage the threads and then grind the tip to the desired diameter. Using a diamond wheel and a mister you plunge grind the spindle, just have to be careful not to get it too hot. Not a big deal to accomplish.

 

[BoydAllen]

IMO calipers are never the right tool for exact measurement of neck thickness. In a pinch, a good .0001 1' mic. can be used to measure with a bullet seated, but a specialty mic. that has been designed for the job is the best way to go. Luckily, there are some inexpensive ones that I think would do a good job for most. Lyman used to sell one, and now RCBS lists a similar one. A long time ago, I handled and briefly use the Mitutoyo that K&M has sold for a number of years. It is a quality piece.

 

[STS]

I took mine to a machine tool supply house that offered sharpening services. I don't remember now what they charged me but it wasn't all that much.

 

[c.k.93]

Well I solved my problem with blunt micrometer spindle. I called up K & M Precision Shooting Products and talked to a very nice man. He said no problem, they do a lot of "sharpening" on Mitutoyos. He said he was going to set up to do a batch of mitutoyos and to send it asap. He quoted me ten dollars to do it and $5.80 for return postage. I can't be happier for $21.60. Thanks for all the help, problem solved.

c.k.93

 

[mr45man]

That man would be Roger at K&M.
Many good dealings with him over the years.
John H.

 

[fdshuster]

c.k.93: Thanks for the info. I did as you, called this morning, spoke to Roger & the micrometer was sent out priority mail shortly thereafter. He quoted the same price.

 

[Alex Wheeler]

Just saw this thread, sounds like you have it handled. There is a carbide insert on the end of the spindle. Unscrew the spindle all the way then remove the thimble. I put some tape on the threads as they are very delicate 40 tpi and easy to damage. Use a diamond grinding wheel to sharpen. I chucked mine in a drill and turned it while grinding. Came out great.