thread mic??

S

skeetlee

Active member
I am tired of messing with thread wires, so i am going to buy a decent thread mic. My question is do i need a 0-1" mic or a 1-2" mic for a 1.060 diameter tenon? Will the mic read major Diameter, or will it read down into the threads? I may just buy a set of each depending on price. Can someone please tell me what set i need? thanks a bunch. Lee
 
skeetlee said:
I am tired of messing with thread wires, so i am going to buy a decent thread mic. My question is do i need a 0-1" mic or a 1-2" mic for a 1.060 diameter tenon? Will the mic read major Diameter, or will it read down into the threads? I may just buy a set of each depending on price. Can someone please tell me what set i need? thanks a bunch. Lee
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Most thread mikes just cover a range of thread pitches within a diameter. They are OK for miking an original and threading to that size. For best results stick with the wires.
 
You will need a 1"-2" mic for 1.060" dia.thread. Make sure you get one with interchageble anvils and a setting standard. I have both a 0-1" and a 1-2", but they share one full set of anvils. Once you use them you will never want to use wires again.
 
skeetlee said:
Will the mic read major Diameter, or will it read down into the threads?
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Thread micrometers will read the pitch diameter. As MilG said you will need a 1-2" with a set of anvils for threading tenons. Be ready to spend a few $$$. Mitutoyo are great but very expensive, SPI not bad and I've used both.

Mitutoyo w/anvils http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=2615150&PMAKA=601-2131

SPI Micrometer http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=25659635&PMAKA=326-1344

SPI anvils http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=12418297&PMAKA=326-0056

Ultra cheap and probably not worth trying http://www.use-enco.com/CGI/INSRIT?PMAKA=328-6239&PMPXNO=25565492&PARTPG=INLMK32
 
I would buy the "ultra cheap and probably not worth trying" one :)

This is old tech tooling and as one who has measuring tools from tens to hundreds of dollars in price..... THEY ALL PERTY MUCH WORK...

I routinely compare mics and calipers and find the cheapies to agree with the Mitutoyo/Starrett grade stuff. (I don't have any "REALLY" good stuff)
 
alinwa said:
THEY ALL PERTY MUCH WORK...
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Al, I would have to agree as I've used some cheap stuff that works but I like the fit and feel of good tools.

I'll second Thread Pal. Also if you don't have a copy of Machinery's Handbook get one. They are available used all the time.
 
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Jerry is right. Wires and the Machinist Manual will work just fine. Been using this system for over fifty years with never a problem. No reason to make things more complicated and expensive.
 
full profile cutters

Ever sense I started using full profile cutters I haven't had a need for wires or a thread mic. They work great.
 
A full profile cutter also cuts the top or major diameter. If you are cutting a barrel thread and have a tenon diameter of 1.062" cut the tenon big say 1.067".
keep measuring the tenon with a mic and when the diameter gets to 1.062" your threads are done.

You can get them from Enco or any major tool supplier. The down side is you need to buy a insert for each thread pitch, but is sure is easier than the three wire system.
 
That sounds interesting. However i am not sure i can get FP inserts for my Kennametal holder. I will have to look into it. Lee
 
tools

I use a Carmex SER 0500 F16 tool holder and a Seco insert # 16ER 16UN CP500 for 16 pitch threads. You can find them at Enco.
 
Also as pertaining to the full profile threading inserts. BAT and Kelbly use a 1.0625 tenon Dia with an 18TPI. However the thread depth is a bit deeper on the BAT. That is if my memory serves me properly? Without my notes I hope im saying this properly. I know for sure one of the actions, BAT or Kelbly, one has a bit deeper thread than the other. About .003 I do believe. Without wires or a mic, how could you trust your Full profile insert?
 
skeetlee said:
Also as pertaining to the full profile threading inserts. BAT and Kelbly use a 1.0625 tenon Dia with an 18TPI. However the thread depth is a bit deeper on the BAT. That is if my memory serves me properly? Without my notes I hope im saying this properly. I know for sure one of the actions, BAT or Kelbly, one has a bit deeper thread than the other. About .003 I do believe. Without wires or a mic, how could you trust your Full profile insert?
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Install your insert, thread a tenon with wires to size then mike the finish diameter that the profile insert cuts. Then you can go on from there. I would stick with wires if I didn't have inspection gages.


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Thread mic

Lee,

I am a Toolmaker by trade and yes, enjoy and use and buy the best tooling for our shop where I am employed. I work for a medical devices company and can purchase whatever tooling I choose.

However, for my home shop where I do my own gunsmithing work, I am quite frugal. I bought a 1-2" thread mic with anvils off of Ebay for $59.00. Brand new! Yes, "Chinese junk" but when I received it I checked and calibrated them and found them to be perfectly fine for barrel threading. Pitch diameter measurements come out the same as with wires without having to do any math or having to fumble with wires.

I think you will be happy when you get a thread mic and there are plenty of folks on this site that can help you with any issues or questions that you may come up with when you start using them.

Jerry
 
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