AmericanLongRifles Forums
General discussion => Black Powder Shooting => Topic started by: Kurt on September 25, 2025, 02:07:06 AM
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This has been covered well on this forum, but I thought I'd add this for information. I have been working with a rifle and trying varying thicknesses of patch material. To do this, I purchased Ox yoke patching by the numbers, .010, .015, & .018. I checked these thicknesses with both my calipers and micrometer, and what I found was that to get the measurement stated on the packaging, I turn the micrometer gently still it stops, and thumb roll the calipers till they stop. No pressure applied. I know some say to apply pressure, but I believe this is a reference to attempting to duplicate patch material already successfully used. My point is that if you are buying material online or in a store marked to a certain thickness, the method I have described is the size.
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I am also having the same problem with the calibers!
How do you determine how hard to squeeze?
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I squeeze as hard as I can. When you load the ball you squeeze the patch between ball and bore so you get a good gas seal and no blow by
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Exactly as the Grouch noted.
Doing so 10 ounce denim for me measures .021".
The 10 ounce denim i bought prior, measured .0225".
The new thinner material seems to work well in all my guns.
In my honest opinion, if you buy 10 ounce denim, you will have the best material for normal rifling depths.
For deeper rifling, I would suggest 11 or 12 ounce denim.
I have ZERO use for any patch material that is thinner than the 10 ounce denim I have.
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My point is, if you are buying patch material ready-made, marked say .015, it will measure .015 when you apply the slightest pressure, making the mic or caliper stop. So if you apply a hard squeeze and get a measurement of .015, you'd better buy patch material marked .020 at least.
If you used the squeeze method on what you have, that works, and go to a fabric store to buy more, duplicate the measuring technique there.
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Kurt, spot on in my limited experience purchasing pre-cut patches. For those buying fabric and using their own method of determining thickness, all that matters is consistency. Use their own method same measuring device the same way. I like Daryl’s advice on “ounce” fabric and sticking to denim which typically is very standard in weave. I used to buy cotton fabric willy-nilly (cheap son of a gun) and don’t do that anymore.
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Thanks. I need some new patching material, now that Joanne's is closed. Can someone recommend where they are getting the 10 oz denim?
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Just on the news last night. Joanne,s sold out to Michelle's and they claimed they would continue selling fabric. ????? Time will tell I guess. :-\
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I too have found that the 10oz denim from Joannes that mics at .021 works best for mine.
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Thanks. I need some new patching material, now that Joanne's is closed. Can someone recommend where they are getting the 10 oz denim?
Wally-World or Hobby Lobby should have some
..
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BIG DUCK CANVAS sells what you need
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As far as canvas is concerned, I did purchase a couple meters (39 1/4" approx. per M) for testing. For me it measured .021" and gave a good seal. The washed material was slightly harder, not as soft as the denim of the same thickness.
If I could find more of the mattress ticking we had a bunch of years ago, I'd buy the whole bolt. Washed twice, it was extremely supple, and measured .0235". It loaded as easily as the .021" and .0225" denim. light blue, white, dark blue and red stripes. Wonderful patch material. Our yard-goods store said they could no longer get get it.
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Thanks. I need some new patching material, now that Joanne's is closed. Can someone recommend where they are getting the 10 oz denim?
I read yesterday that Hobby Lobby is re-introducing the JoAnne product line into their stores. How extensive it will be was not mentioned.
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I know this subject has been beaten to death but here's my 2 cents worth. Once you find the material and thickness you like wait for it to go on sale and buy a whole bolt of it. Store it in a dark Rubber-maid tub and it will last for years if not decades. If kept in a tub away from light and excess humidity it will not deteriorate as some say it will. I have 2 bolts of the material I use the most both are just like new and are 8 years old.
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Stored in my basement, my material remains as good as new, but it doesn't last me that long. I only buy 3 meters at a time.
I should have bought that bolt of mattress ticking.
Our Hatchet Jack did just that, then moved 500miles South to down near the 49th parallel, taking it with him, of course.
Good advice to buy the bolt, Mike.
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I have observed wildly different procedures for measuring patch thickness. How hard to squeeze is subjective. I have had to re label patch material because I got a different measurement when I checked it later.
Unless we had some kind of standard measuring device that put known pressure on a known area we can not compare patch thickness from one person to the next.
I do not tighten the mic as hard as I can. That gives a bad measurement with any substance. It springs the micrometer. If you do that with a standard bock it will measure under the known size.
That said, I do something more moderate and repeatable. I go a little more snug than the clicker. OR, with a digital caliper, I go thumb snug, whatever that is. I do not strain my tools by going super tight.
When shopping for patch material I bring some old patch material that is working well. I then buy more material that measures the same as the same time using the same compression procedure. The amount of pressure is irrelevant if you do it the same for both. The two measurements will be comparable.
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I own two different mics and 3 different makes of dial calipers.
All give different measurements when operated as closely to the same as I am capable.
I no longer use the micrometers and only the Hornady calipers as they gave the middle reading of the three makes I own. Those readings were consistently . 001" apart.
When measuring, I squeeze the tines of the calipers between the thumb and forefinger as tightly as I can using my right hand. I get VERY consistent measurements using this method, day to day and month to month on the same material.
For me, the store bought patch material was listed as being 3 thousandths thicker than I measure with my method of measuring.
As to the mic, my Mitutoyu, when cranked down hard on the tightening barrel will measure 14 thou. denim as .002". With the calipers, I see .034" for this same piece of material with my thumb and forefinger squeeze.
I get the same measurements right or left handed.
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I quit using dial calipers for measuring patch material when I ran on to an old Ames snap mic at a friends garage sale. It regulates the pressure, and reads the same measurement every time. No more worrying about not feeling particularly strong that day, or weak either, or arthritis flare ups in the wrist and thumb. Plus the added fun of going into the fabric store with it. The people in the fabric store may have seen a regular dial calipers, but that snap mic really gets attention.
Hungry Hores
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As a 20+ year machinist, I’ll offer a note about using calipers and micrometers.
Are your tools set to a standard use to verify the calibration? They are not expensive to find used on EBay. How to use? Close your jaws of caliper or mic on a piece of paper and slide off edge of paper. This cleans the measuring face. Now do the same to each end of the standard on the paper to clean the ends of dust. Then gently close your mic or caliper on the standard. I’ll use a 1” standard as an example. Your micrometer might be a friction thimble it ratchet thimble or just a straight tight loose style. On the first two, you slowly come onto the standard then when the gripping knob spins or ratchets, it’s tight enough. On a style that neither spins nor ratchets, you gently close on it until snug. The standard stays in the jaws without needing to be held. Then that’s tight enough. Check your reading on your mic and adjust the spindle with the tool that they usually come with. It should read exactly 1.0000”.
Then remove the standard and screw back down to fully closed but use the same force as on the standard. It should read exactly 0.0000” if set correctly. And yes, you could check this first and adjust to exact zero then measure your standard and it should be reading perfect.
Last note on this, I was taught to never store your mics or calipers with the jaws touching. Leave them slightly start to let air circulate on the tips. And first thing you do every time when using is close the jaws on paper then pull off, check zero then you are ready to measure.
Most mics are accurate to at least a tenth of a thousandth or .0001”.
Calipers are not guaranteed to be more accurate than +/- .001. You should be able to accurately measure to close to that if you do it accurately and repeatable and your calipers are in good condition and calibrated BUT…the person holding them must be measuring correctly with the proper pressure.
Clean jaws as described above then close. Hold up to light. Can you see through the inside measuring jaws or outside jaws? If you see light then something is out of spec. Both sides should be perfectly touching and no light. Iff the OD measuring side of jaws are flat and the ID side of jaws are apart when you cold slide a feeler gauge in there or paper, just know that the ID side is always off and this isn’t fixable by reasonable means. If you’re only measuring the outside of parts then this will still be a useable tool.
When you check calipers on a standard, you will discover how easy they are to overflex and cause erroneous measurements. You can easily flex calipers and be off by .003” or more in your measurement.
Now I understand what you are saying about the compression of the fabric but don’t squeeze the calipers more than you squeezed on the standard that gave an accurate measurement.
I don’t mean to be wordy or overly simplified note but I am reading many comments that will not give an accurate reading.
If I were to measure fabric, I would use a micrometer and do as described but I’m also verifying that they are reading accurately first.
I hope this helps someone.
Bryan
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All sounds good advice Bryan, however with patch material that gets compressed between the tops of the lands AND the bottoms of the grooves with what I call a "good" combination, also "needs" in my most humble opinion, to be heavily compressed. The "trick" is to do it the same each and every time. With practice(I have 53 years of practice now) one can get accurate enough measurements at the yard goods store, to achieve consistent results. I find the ounce weight given by some yard goods producers to be accurate enough. I suggest 10 or 11 ounce denim should suffice for most anyone.
Of course there are those who will still use .010" to .015" material, and have to either SWAB their bores every 1 to 3 shots.
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If you find the information on how made-to-order patch measurement designations as I measured them useful, that's great. I'm happy to contribute. If you think it is wrong, please let me know. Either way, it won't be a pea under my mattress
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As I remember - The OxYoke .020" measured at .018" only .002" too thin - not usable except in the .32 with only .006" rifling. Their .018" measured .015" for me and sealed in the .32, BUT did not shoot as well as the thicker .018 patches. Their .015 was a mere .012" & unusable for anything.
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But you said you squeeze your calipers, right? Or, apply compress, whatever?
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Squeeze the tines HARD between thumb and forefinger, I thought I'd noted.
Pushing hard with the roller did not give me repeatable results, not sure why.
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A micrometer allows you to crank pretty tight. I’ve kept an old Starrett micrometer in my box since I was in high school. Seems un-natural to bear down that hard on such an instrument but it gives you real world results on patching.
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With the mic, I found using just the ratchet, gave me results VERY repeatable, but .005" thinner than the calipers as I noted.
Taylor's Sterrets, when used exactly the same way, gave measurements .002" thicker than mine as his ratchet was not as strong as mine.
I find squeezing the tines of the calipers to give the best readings. This, after many decades of testing different methods.
We must remember the material is heavily squeezed between the lands, grooves and the ball.
Lyman's BP Handbook had a VERY good picture of the patch/cloth markings on a ball pressed into the bore and removed. It had VERY heavy cloth markings on the ball from the lands, yet still had cloth imprint markings on the ball from the bottoms of the grooves.
I have found my method of measuring, when adding to the balls diameter and equaling .003 to .005" LARGER than the groove to groove dia. gives me exactly the visual that Lyman had shown in the book noted. THOSE combinations seal ALL the powder gasses behind the patched ball.
We are all individuals and will use whatever suits us. Some like thumb stared loads andike to swab the bore more than shooting. Others like to be able to shoot all day with never having to swab the boe and get superior accuracy, unchanging, all day long.
Each to his own.