Pin Gauges, what to buy and how to use

[rockydoc]

I have a S&W model 14-3 that I believe has a constriction in the barrel where it threads into the frame and the cylinder throats are not all the same diameter. I would like to correct these problems by lapping. But first I need to confirm my diagnosis by gauging the barrel and cylinder throats. If treatment is necessary I would like to be able to be able to check my progress so that I will know when to stop.

I read the article by Fermin Garza relating to leading and other revolver issues. He used pin gauges for the purposes I mention here.
My question for you here is where to get the pin gauges and what exactly to ask for (sizes, class, etc.) I Googled "pin gauges" and found sets of 250 gauges for $150 and up. I don't think that I need that many gauges for this project.
If I buy individual gauges sufficient enough to do the job described above what gauges do I need?
Thanks for any suggestions.

[DougGuy]

You could send the cylinder and have it reamed and then lapped for a lot less than you can buy the tooling to do it yourself. Lapping alone is the "Bubba" way of enlarging throats. It works but there is no way of keeping the lap from lapping an oval hole, a belled hole, an eccentric hole or a slanted hole. The reamer ensures the throats are *round* when finished and the lap then smoothes out any tool marks left by the reamer. You want to do the least amount of lapping that the job requires after reaming.

[huntrick64]

For that type of measuring, the $80 set from ENCO is good enough. I bought the -.0002 accuracy set from .250 to .500. I bought them for the purpose you stated and have used them for a bunch of other things as well. Don't tell your buddies that you bought them or they will borrow then and not take care of them. Again, the durability of the cheap ones is limited, but if you are careful with them, they will work well.

For one or two guns, just let a pro do the work and spend your time loading boolits. Doug is right, if your cylinder throats are tight, have someone ream them first before you firelap (if firelapping is in your plan). If not, you will just be wallowing out the throats before the boolit gets to the constriction. Also make sure that your boolits (after loading them up with lapping compound) are not larger than your newly reamed throats or you will screw up what you paid someone to fix. Using my 45 colt Bisleys as examples, the constriction was about .002 - .003. My throats were about .451 from the factory. I reamed the throats to .4525, then took .450 boolits and embedded compound until they ended up around .451 - .452. That was large enough to hit the constriction, but not large enough to cut away at my new .4525 throats. There will still be a little wear in the throats, but they only see 1/6th of the boolots that the constriction sees.

[Bigslug]

My question for you here is where to get the pin gauges and what exactly to ask for (sizes, class, etc.) I Googled "pin gauges" and found sets of 250 gauges for $150 and up. I don't think that I need that many gauges for this project. . .

But what about the next project? Buy the set. It'll pay you back later. You'll use it for every revolver you bring home, and they come in really handy if you need to lap out say. . .the gas check shank area of a mold casting small. Once you have them, you'll wonder where they've been all your life.

[jlkehoe3]

I just ordered 4 pin gages to check my Blackhawk. Ordered from Newegg.com. Price--10.00 including shipping. I think they are Z minus.

[Rifle 57]

rockydoc do yourself a favor and listen to Doug and have Him or someone else that has the proper tooling do the job for you.

[Leadmelter]

For that type of measuring, the $80 set from ENCO is good enough. I bought the -.0002 accuracy set from .250 to .500. I bought them for the purpose you stated and have used them for a bunch of other things as well. Don't tell your buddies that you bought them or they will borrow then and not take care of them. Again, the durability of the cheap ones is limited, but if you are careful with them, they will work well.

For one or two guns, just let a pro do the work and spend your time loading boolits. Doug is right, if your cylinder throats are tight, have someone ream them first before you firelap (if firelapping is in your plan). If not, you will just be wallowing out the throats before the boolit gets to the constriction. Also make sure that your boolits (after loading them up with lapping compound) are not larger than your newly reamed throats or you will screw up what you paid someone to fix. Using my 45 colt Bisleys as examples, the constriction was about .002 - .003. My throats were about .451 from the factory. I reamed the throats to .4525, then took .450 boolits and embedded compound until they ended up around .451 - .452. That was large enough to hit the constriction, but not large enough to cut away at my new .4525 throats. There will still be a little wear in the throats, but they only see 1/6th of the boolots that the constriction sees.
Do you remember the SKU for your set?
Leadmelter
MI

[DougGuy]

Pin gages for revolvers need to be Z minus. These are ground .0002" smaller than the stated size. This works the best for how we use the tool. You want a range that covers all of the examples in a particular caliber if you are going to work on cylinders and barrels. You only need enough to do your own cylinder IF you already know the smallest throat's size.

For a .35 caliber cylinder most S&W and Ruger will be somewhere near .357" but some may easily be .3595" or .360" if Bubba has gotten to it before you bought it. You DO need the incremental sizes so if you start at .356" get each size in half thousandth increments up to .359" This is 7 gages, and I recommend Meyer Gage Co. for singles. They have a $25 minimum order and these should just about get you there, prices are very reasonable as is shipping.

[Virginia John]

Send it to Doug, he does all mine and he is very good and reasonable.

[huntrick64]

Do you remember the SKU for your set?
Leadmelter
MI

From my ENCO invoice:


616-8131
.251-.500-.0002 PIN GAGE SET
1
$79.00
N
$79.00

[Ballistics in Scotland]

Most professionals and enthusiasts will find uses for many others in the set, but others will never be used at all. You can buy individual gauges on eBay, including carbide ones, sometimes from China. These, including their sets, should be accurate enough, but most people at that level already have a micrometer to check it with. If you establish that a chamber mouth is .357in. it doesn't matter whether the pin gauge has .358 written on it. More of them are nominally metric, but 25.4 to the inch is accurate.

A split ball gauge and micrometer are also useful. That isn't quite as accurate, but has the advantage of detecting ovality.

[rockydoc]

From my ENCO invoice:


616-8131
.251-.500-.0002 PIN GAGE SET
1
$79.00
N
$79.00



The current price is $95.95 plus shipping when ordered on line. I just ordered one. I will measure the throats and bore and send the cylinder,or maybe the whole revolver to Doug to straighten everything out,

Thank you all for your responses. Rockydoc

[Geezer in NH]

I would send it out. It gets done correctly for one and will most likely end up cheaper IMHO

[MT Gianni]

You still need to measure to know if it needs to be sent out. They are a great tool for buying used handguns.

[44man]

Never found a use for them and will not buy any. Doug can fix.

[Hickok]

Send it to Doug, he does all mine and he is very good and reasonable.I'll second that! Send it Doug, he does excellent work.