go gauge

[whiskey08]

I have a question

i want to make a go gauge for a rem 700 action. Major diameter for a threaded barrel is supposed to be 1.062"

from what ive gathered when truing an action, anywhere from .005 -.010 is the norm needed to clean up the threads in the action.

so I want to make a go gauge with two major diameters: 1.072 if only .005 is needed to tru up the threads, and 1.082 if .010 is needed.

is my math correct, and does the major diameters of 1.072 and 1.082 sound right from your experinces.

thks

 

[firearmdoc1]

The measurement you provide implies +.010" minimum and +.020" maximum over the nominal size of 1.062".
A gage will do nothing but tell you that you have threads somewhere between your minimum and maximum gages. You still don't know what the actual size of the threads are.
How do you intend to re-cut the threads, cut single point or with a tap?

 

[larry 1944]

The major Dia. of a thread is not to important. What you need to be concered about is the pitch Dia. Read up on it in the Machinery Hanfbook.

 

[whiskey08]

the purpose of the go gauge is..

lets say i need over .007 of cleanup (which is +.014 to the major diameter) then i auto majically go till my go gauge of 1.082 (which equals +.020 on the major)

so the whole purpose of the gauge is, to tell me what the major diameter of the barrel shank needs to be, also what the recoil lug needs to be.

Larry1944
never heard of pitch diameter? a rem 700 has a tpi of 16, major diameter of 1.062. Are you referring to minor diameter? if so there are equations for that. However pitch diameter is not one of them.

After additional resea,rch PTG makes a expanded recoil lug for 1.080 so thts what i think ill make my go gauge for. One end will be 1.072 and the other 1.080

 

[Gundoktr]

You need to read up on some basic Machine Shop stuff. Why go through all that work just to find the major diameter of the barrel threads when you could just use your dial calipers to measure it.

 

[jonbearman]

If you go .010 that equates to .005 on a side.You dont want to take .010 on a side as it would equate to .020 you will have taken to increase the thread size.

 

[whiskey08]

Gundoktor
I'm wondering which book of basic machine shop stuff shows u how to measure the major diameter of internal threads on something like an action with a pair of calipers

The purpose of the go gauge will be to tell me what my major is. I'll single point the threads until my go gauge goes in then when I go to cut the threads on the barrel I just use the dimensions from the go guage

 

[larry 1944]

As I said before you need to read up on threads. Major Dia. is not the most important. Pitch Dia. is the measurment that means the most. You need go & no go gauges made by a tool maker. You could make your own using wires to measure the pith dia.

 

[Gundoktr]

Gundoktor
I'm wondering which book of basic machine shop stuff shows u how to measure the major diameter of internal threads on something like an action with a pair of calipers

The purpose of the go gauge will be to tell me what my major is. I'll single point the threads until my go gauge goes in then when I go to cut the threads on the barrel I just use the dimensions from the go guage

It is called the book of experience!

 

[whiskey08]

the book of experience? How about a forum that people share ideas on?

please enlighten us with how to get the major diameter of the internal threads on a rem 700 action with a pair of calipers.

it amazes me how hard everyone tries to circumvent the question, and tell you how your wrong. but never ever come close to sharing constuctive knowledge or ideas.

I guess thats what old hens do when they dont have an answer,

 

[Gundoktr]

Dial Calipers, use the end that you would use to measure and inside diameter or a bore.

When I true up an action, I thread it until I have all of the runout gone; it has taken as much as .028" on one. The last cut I take is with the threading cutter set back to Zero and fed into the action just enough to clean up all the way around, maybe .020 or so. You then take your caliprs and measure that diameter. It will be close enough to major diameter than you care about, I usually rjeduce that diameter by about .005" so as not to leave a sharp crest on the thread, a slight flat.

Why you would want to clean up to only .005 or.010 and not finish cleaning up all the runout is beyond me. Next step would be to thread your barrel to fit the action.

Clear enough???

And your message was clear enough on the "old hen" comment, smart ass.

 

[jscandale]

Whiskey,

I think you have a good idea and while it's nice to have a go, no go gage, these types of gages can only tell you a yes or no answer, but not really to what degree of yes or no since they are of a fixed nature.

May I suggest that you use a standard 1" thread mic to measure the dimension from internal thread root diameter of the action thread to the exterior of the action diameter? This dimension multiplied by 2, then subtracted from the outside diameter of the action would give you the major diameter of the threaded tenon of the barrel shank.

I have a thread mic just like this for just such a thing:
http://www.amazon.com/Starrett-210AP-Comparator-Micrometer-Graduation/dp/B0006J4S26

At the very least, your before and after measurement will give you a finite amount of how much material has been removed from the action threads.
This may be an easier alternative to your end goal. Hope that helps.

JS

 

[whiskey08]

Gundoktor

i understand using the calipers to measure the inside of a bore (albeight an inaccurate way to do it)

when u do that u are measuring the minor diameter of your threads. Not the major needed for the purpose of turning your barrel shank down to.

Ive got two barrels sitting here and the difference between the maj and minor of a threaded barrel is easily .060.

The question was, in you guys experience, is there a range that will generally cover most actions? Granted there is always exceptions to any rule. If there is a range that is a norm, then a go guage would make sense. I also like the idea of a go guage set to 1.080 which is the same size of PTG's oversize lugs.

Jscandale

i like your idea and that tool, is it your experience that generally you need more than .010 to clean up the theads on a rem action?

Im waiting on the liscensing process before i can start advertising, so ive been making tools and fixtures in the mean time. Tying to cut down the amount of $150 tools on my list of stuff to buy.

Thks to all
W8*

 

[jscandale]

W8,

To be honest, I don't do a lot of action truing but can do it. It's no harder than any other exercise. I'm sure that if you talk to a variety of guys, they' tell you that the threads will clean up within .005" per side, but there are those exceptions...
About the tools, not to sound like a smart guy, but I have drawers of tool boxes full of $150+ tools to include mics, indicators, gauges, etc. that just add up over the years. The mic that I posted can be found on ebay for about $60-70. Just look for one in good shape.

JS

 

[Dans40X]

whiskey08,
On a simpler note-
To bore the I/D of your recoil lug-
Would you gage pin the inner diameter or mic the I/D?

As mentioned in previous posts,
A gage will provide you w/ a go-no go,not a pitch diameter measurement.

 

[rem78822br]

Whiskey 08,
When you are rethreading an action and make your last pass with the threading tool, this will be your major diameter for your shank. If you zeroed your tool and run it in as a boring bar at the same setting as your last pass, basically cutting a thread relief, then this relief will be at the same major diameter as your new threads and easily read with a caliper. Only need to go in .050 or so. Very simple and exactly what Gundoktr told you.

 

[whiskey08]

Dans40x

a gage pin would be accurate, i think for the purposes of a recoil lug, calipers would be more than close enough

in a sense the gage would provide me with a measurement, because the gage is set to what ever major diameter i want or need it to be. just for arguments sake i could have a piece of stock threaded at both ends at 1.072, and 1.080. So if took off .005 and it didnt clean up the threads then id automatically keep running passes till my go gage of 1.080 goes in then that becomes my measurement for the lug and major diameter of the barrel shank.

 

[shortgrass]

This has become the 'norm',,,,,,,,, making a simple job as complicated as can be imagined. Every forum I visit has this kinda' stuff.

 

[Erik Cortina]

It's actually really easy.

If your factory major diameter is 1.0625", and you bored it .010" over, then the new major diameter is 1.0725"

If you want to have a 1.080" major, then bore 0.0175" over factory and thread until go gauge fits.


Now for the really easy method.
Make your go gauge at whatever you want it to be. Then buy you a laydown full profile threading insert, and chase threads until it go gauge fits. The full profile insert will take care of threading and boring at the same time.

 

[Gundoktr]

Gundoktor

i understand using the calipers to measure the inside of a bore (albeight an inaccurate way to do it)

when u do that u are measuring the minor diameter of your threads. Not the major needed for the purpose of turning your barrel shank down to.

Ive got two barrels sitting here and the difference between the maj and minor of a threaded barrel is easily .060.

The question was, in you guys experience, is there a range that will generally cover most actions? Granted there is always exceptions to any rule. If there is a range that is a norm, then a go guage would make sense. I also like the idea of a go guage set to 1.080 which is the same size of PTG's oversize lugs.

Jscandale

i like your idea and that tool, is it your experience that generally you need more than .010 to clean up the theads on a rem action?

Im waiting on the liscensing process before i can start advertising, so ive been making tools and fixtures in the mean time. Tying to cut down the amount of $150 tools on my list of stuff to buy.

Thks to all
W8*

If you go back and read my reply, you will note I do not reference the minor diameter/inside diameter. I stated to take a slight cut, about .010" deep, into the face of the receiver with the threading tool set on the last cut of the threading tool. This will give you the dimension you need, the major diameter of the barrel thread.