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Spare Parts to keep on hand?
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floydthecat View Drop Down
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    Posted: Oct 17 2021 at 11:15am
Originally posted by Rebel92 Rebel92 wrote:

6 in. Composite Digital Caliper (harborfreight.com) 

is this the el-cheapo you had in mind? anything that price has me curious. 

Nope….mine are stainless steel and in a hard case. I don’t know if I would trust those plastic ones either? Maybe I gave a little more than $10, but it was not much more. My wife gives me $20 and takes my wallet and credit cards before she allows me to go shopping.
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Points: 1902 		Post Options Post Options   Thanks (1) Thanks(1)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Oct 17 2021 at 8:18am
Originally posted by Matt_X Matt_X wrote:

I don't know what the tolerances are with a digital caliper but my guess is any offset will be either the same or linear.  In other works if it reads .001" closed (zero), then it will probably read .036" on a .035" feeler gage.

Just out of curiosity I grabbed a handful of feeler gauges to check my cheap Harbor Freight $10 digital calipers. Spot-on with the feelers. Couple of times a gauge would read off by .0005 (.0235 vs .024 feeler), but most of the time the reading matched the gauge. WAY better than government work.
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Points: 960 		Post Options Post Options   Thanks (1) Thanks(1)   Quote Smokpole Quote  Post ReplyReply Direct Link To This Post Posted: Oct 17 2021 at 7:11am
I prefer dial calipers. They are easy to check the zero on and adjust when needed. Plus they are easier to read with a good sized dial.
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Matt_X View Drop Down
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Points: 705 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Matt_X Quote  Post ReplyReply Direct Link To This Post Posted: Oct 16 2021 at 4:32pm
OK. I don't know where my brain was the other day.
If you ever changed your own spark plugs then you have some sort of half decent feeler gages.

When dealing with a caliper or micrometer of uncertain calibration.
a) clean the jaws with a piece of paper.
b) check the zero measurement.
c) check the measurement against a feeler gage.

I don't know what the tolerances are with a digital caliper but my guess is any offset will be either the same or linear.  In other works if it reads .001" closed (zero), then it will probably read .036" on a .035" feeler gage.
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I've got a Hornady branded caliper that I think I paid close to $40 for, it is made in China, it works fine but is probably made in the same place that the Harbor Freight caliper was.
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Points: 1902 		Post Options Post Options   Thanks (0) Thanks(0)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Oct 13 2021 at 5:45pm
Certainly nothing wrong with buying a better quality tool. There is a tolerance to about anything. A couple thousandths off one way or another is not going to matter in this case. These are what I use for everything, even reloading. If all you plan to use it for is checking head space on occasion, these are fine. Now, if I were a gunsmith or machinist I’d probably toss them in the trashcan. You can read where guys have measured their head space gauges and find them off by a tad vs. the published dimensions. The craftsmanship of the gauge and tolerance of the measuring tool are at work. Then you have human error. When you get down to measuring in terms of ten thousandths or even thousands, how tight to fit the instrument can vary and any two times you measure the same thing may be different.
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Points: 705 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Matt_X Quote  Post ReplyReply Direct Link To This Post Posted: Oct 13 2021 at 5:37pm
Oh I didn't mean another caliper, I meant something that could act as a gage block. Or if you have a friend nearby who has a gage block.   I can't think of anything common off the top of my head but maybe someone will. 

Also I may be more picky than others.
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Points: 541 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Rebel92 Quote  Post ReplyReply Direct Link To This Post Posted: Oct 13 2021 at 5:24pm
unless someone (Floyd, you, or anyone else) shows me a better alternative, I will probably end up buying a somewhat nice one instead of buying a POS and having to buy another one to check it with. 
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That is cheap!

I use a vernier caliper. LOL  I think dad bought from Sears in the 70's.
Never looses calibration if treated right and no batteries to go bad etc.
All it needs is a good eye, or these days for me that means a magnifier or at least reading glasses. LOL

I'd be Ok with a cheapy like that if I had something of known thickness to compare with ever so often. 


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6 in. Composite Digital Caliper (harborfreight.com) 

is this the el-cheapo you had in mind? anything that price has me curious. 
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Yes.
Not knowing how much the tape compresses, I measured before and after.  Didn't seem to change much.

If it wasn't mentioned, for the tape method the bolt needs to be disassembled.  That way the extractor is not trying to grab a thick rim and also you won't be fighting the ejector. 
I did it because I wanted an answer right away and I have everything needed on hand.
Having a machined gage that allows measurement with the bolt assembled could be real handy in any number of situations where bolt disassembly isn't practical.  I wouldn't feel bad about that purchase at all.
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A Harbor Freight model is inexpensive and good enough. Different brands of tape may vary in thickness, but most I have measured are like 1.5 thousandths.

I considered the use of tape pretty cheesy, until I watched a video of a Smith head spacing a bolt-action target rifle using the same technique. And he was after 1-2 thousandths of space….not 22. 

There are other ways to perform the measurement. You can do it like you would measure an M1 or M14. Feeler gauges between the rear of the right lug and the recess wall added to your case length.
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Points: 541 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Rebel92 Quote  Post ReplyReply Direct Link To This Post Posted: Oct 13 2021 at 3:52pm
guess i need a caliper for the tape method?
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Points: 705 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Matt_X Quote  Post ReplyReply Direct Link To This Post Posted: Oct 13 2021 at 3:49pm
"If it tries to rotate with little or no thumb-assist, it’s on the edge of failing."

Having just done this using your tape method, that's a great description.
I cheated a little. First I used masking tape as it let me get close the go/no go range to something like 2.94 to 3.04"   Then redid it using a stack of scatch tape starting around 2.94   and by 2.97 it wasn't going to fully rotate even with moderate pressure.

It will make sense when you do it. 


Odds of it passing?  I bet the odds are heavily in your favor unless mating surfaces are really worn.
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Rebel92 View Drop Down
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Points: 541 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Rebel92 Quote  Post ReplyReply Direct Link To This Post Posted: Oct 13 2021 at 3:28pm
okay sounds good. so I actually just want it to touch it without beginning to rotate. think I understand. 
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excellent, thank you. What are the odds of the bolt I purchased not headspacing properly? Just curious. 
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Points: 1902 		Post Options Post Options   Thanks (1) Thanks(1)   Quote floydthecat Quote  Post ReplyReply Direct Link To This Post Posted: Oct 13 2021 at 3:16pm
You will feel much better if it doesn’t try to rotate. Pressure is a subjective quantity when it comes to head spacing. Slight-pressure to rotate can mean different things to different people. If it tries to rotate with little or no thumb-assist, it’s on the edge of failing.
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Yes as long as it does not completely close. Also see below picture.
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Points: 541 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Rebel92 Quote  Post ReplyReply Direct Link To This Post Posted: Oct 13 2021 at 3:09pm
thanks. as long as it doesnt go fully into battery is considered "Passing?" or what exactly? 
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Yes, i ordered the Forester Field so it can be tested while the bolt is intact. as long as it doesnt go all the way into battery I am good? Or do I not want it to even begin to rotate downwards? 
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