Go gauge for Remington 700

[AWLEAPHART]

Hello,
I have been researching Single point cutting on Remington 700 action threads. I like the idea of having the 1.075 and 1.077 gauge to use. How do you know the depth of cut when making the gauge? Can you cut the blank .002 bigger and thread with a form tool and let it cut the .002 and you know your at the right depth?
A Leaphart

 

[carlsbad]

Make a male gauge and measure the pitch diameter with a thread mic. That becomes your go gauge.

 

[AWLEAPHART]

I have a few nice mic's but no thread mic.
A Leaphart

 

[carlsbad]

Then you're into 3 wire...google it. After you use it a while you'll wish you had a thread mic.

 

[AWLEAPHART]

I have those too. I guess I need to fine the math to do an odd size. Thanks.
A Leaphart

 

[carlsbad]

all you need

https://littlemachineshop.com/images/gallery/instructions/ThreeWireMethod.pdf

 

[carlsbad]

Ok. So you don't know how to calculate the pitch diameter:

http://theoreticalmachinist.com/Threads_UnifiedImperial.aspx

for 1.075 x 16 tpi a pitch diameter of 1.030 is pretty much right in the middle.

 

[AWLEAPHART]

Over 3 Wires I use my phone Machinist Calculator. Odd size like 1.075-1.077 is not in there.
A Leaphart.

 

[AWLEAPHART]

http://theoreticalmachinist.com/Threads_UnifiedImperial.aspx
This will be the one I use.

 

[Dusty Stevens]

Shars sells a thread mic that works very well pretty cheap.

 

[AWLEAPHART]

I see it -

 

[Shawnba67]

I picked a few thread mic's of ebay scored a 1-2" 14-20tpi for $25 shipped. Course you gotta verify it with the over wires measurenent before you can trust em

 

[AWLEAPHART]

How smaller due you guys normal go on your barrel threads?
Internal threads at 1.077 you turn your barrel tenon to 1.075?
A Leaphart

 

[carlsbad]

Thread fit class theoretically takes account for that. but I prefer to do it by feel. When I thread the tenon, I screw the action on until I have the fit I want. Looser is better than tighter. Don't be tempted to make the threads too tight thinging the tighter fit is stronger or "more precision".

 

[tobnpr]

Are you single-pointing to "clean-up"?

Wondering why you're trying to thread to a spec, rather than just cutting as deeply as needed to get the threads concentric, then cutting the barrel tenon to match (for which you don't need a thread gauge, just cut to fit).

Precision of thread fit between barrel and receiver is not critical. Shoulder mating surfaces, are.
Threads bring the surfaces together. The shoulders align them. JMO...

If you're trying to cut internal threads to a spec- or truly match PD's for a "perfect" thread fit, you need a plug gage.
It isn't as simple as OD's of the A and B threads.

If you don't own a Machinery's Handbook, buy one. It's essential.

This may help:

https://www.alliancecalibration.com/blog/threads-and-calibration-iso-1502-and-asme/ansi-b1

 

[carlsbad]

tobnpr

I don't know what the OP has in mind. We are all a bit obsessive/compulsive in the accurate shooting world or we wouldn't be successful...here are my thoughts on standardization.

I don't true the threads on most remingtons, I find truing the shoulder and lugfaces adequate. But when I do I like to true them to a standard size so we know what to expect and with gunsmithing, barrels are even interchangeable. I like 1.075 for a trued spec diameter but I certainly can't influence the industry with the few actions I true.

 

[AWLEAPHART]

Plan is.
I have a 600 Remington action that I'm going to build into a 6BRX. Face the action,true up the integral lugs and take approx. .010 off the threads. Use thread gauge that I'M going to make and single point cut the threads to 1.077. True up the bolt face and lugs,also change the bolt handle. Don't care for the dog leg in the bolt handle. I have a small machine shop (3 lathes two milling machines) and only do work to my person rifles. I just never have re threaded an action before. Getting all the info I can before I start. Its hot as hell here in SC and waiting a little before starting to hope it cools off in the shop.I'm always open to any idea and love to see different ways people machine but come out with the same product at the end.
A Leaphart

 

[AWLEAPHART]

Carlsbad,
Most Internal thread charts give the maj. dia. for 1-1/16"-16 as 1.0625 and some chart have 1.078. why is this? Was just wondering why all charts don't have the same info?
A Leaphart
0625

 

[carlsbad]

I don't know what chart you are looking at but I would say it is wrong to have a major diameter larger than nominal by that much.

The theoretical machinist link I gave above is good for calculating pitch diameter and giving major diameter max and min.

Just a thought. Maybe you are looking at a chart for internal threads.

edit: yep, class 2B (internal) max major diameter for 1 1/16-16 is 1.078. You are looking at internal threads.

 

[ridgeway]

There are different class of thread fit. There is a pitch diameter specification range for each thread. There is not one exact pitch diameter number for lets say 1-1/16-18 2A thread. Same holds true for a major and minor diameters. If you turn a tenon for the above external thread, you won't turn the major to exactly 1.0625". You will turn under that let's say 5 thou or so. Anything you want to know about threads is laid out in extreme detail in the machinery handbook. Makes for a nice bedtime reading book, lol