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General discussion => Black Powder Shooting => Topic started by: R.J.Bruce on July 12, 2019, 05:13:38 PM

Title: Measuring patch material, or pre-cut patch thickness
Post by: R.J.Bruce on July 12, 2019, 05:13:38 PM
Of the hundreds of posts here on ALR that I have read concerning the thickness of patch material/pre-cut patches; I can't recall a single one where the poster mentioned using a micrometer to measure the thickness of the material.

Every single post mentions using a caliper to measure thickness.

In many cases people talk of REALLY  squeezing the caliper tightly together in order to achieve a proper measurement.

I haven't worked as an apprentice machinist since I was in my early 20's in the 1970's.

I was taught that there were tasks where a micrometer was the proper tool for measuring, and other tasks where a caliper was the right tool for the job.

I am well aware that because cloth is a compressible substance, that it is more difficult to measure accurately.

It seems to me that measuring fabric thickness with a quality steel micrometer would make more sense.

Such as a Starrett, or Brown & Sharpe.

Rather than a caliper, especially one of the inexpensive fiberglass dial calipers.

Am I wrong, or am I missing something since I quit being a machinist after 4 years in?

Just trying to be helpful to those struggling to figure out the proper thickness for the patch material for their particular rifle.

Thanks,
               R.J.Bruce

Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: nemovir on July 12, 2019, 05:20:02 PM
Really? I've never notice that the word 'caliper' was used rather than 'micrometer', but when measuring fabric, a micrometer is to be use.   I wouldnt use an expensive one such as Starlett, a cheapo brand is recommended.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: R.J.Bruce on July 12, 2019, 05:56:29 PM
Nemovir,

A vernier caliper, whether it is the old style with engraved bars, or one with a dial or digital readout, is not a micrometer.

They are two entirely different measuring tools.

I was suggesting in the OP,  that because of the much larger surface area on the faces of the jaws of the caliper, that it might be cause for greater difficulty in getting an accurate measurement.

A quality STEEL measuring tool is ALWAYS going to be more accurate than a lesser quality plastic tool.

That being said, in 2019, it is certainly possible to manufacture a very accurate measuring tool from plastics that will rival in accuracy a good steel tool. In fact, I am sure there are environments in which a steel tool would be dangerous to use, and for which extremely accurate measuring tools created from non-static plastics already exist. But, I would be willing to bet those tools cost as much, or more than say, a Starrett steel tool.

R.J.Bruce

Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: nemovir on July 12, 2019, 06:20:48 PM
micrometer is the one that looks like a horseshoe with a handle. right.  Dutch Schutlz recommend not buying an expensive one. he recommend sear brand.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Mike_StL on July 12, 2019, 07:07:31 PM
And Dutch recommends really tightening the micrometer to compress the fabric.  Dutch really is adamant about assessing the compressibility of the fabric.  I think that looking at the closeness of the weave being  a better indicator of performance when the patch is under pressure on loading.  While tightening he jaws of the micrometer will compress the fabric, a micrometer is a precision instrument and machinists and tool makers cringe when they see someone over tighten one.  I only did that once in front of my tool maker father and I still won't.  I use the tension clicker on the micrometer to do minor compression.

Jo Ann's cotton drill utility cloth will measure 0.016" on slight slip to 0.015" on the clicker and you can compress to 0.010" when you really crank down on my Harbor Freight micrometer and it measures within 0.001" of my Starrett or Mitutoyo at reasonable contact. Be aware that the measurement at the store of the fabric with sizing will change after washing and drying. One can expect that micrometer compression may read about 1/3 less than a touch measurement.  Dutch chided me once for making measurements of cloth the same way I would measure thickness of metal.  I see no need to abuse precision micrometers if you get the information you need from normal use.

Some of the Denims at Jo Ann's Fabrics are good choices as well.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: nemovir on July 12, 2019, 07:16:17 PM
Some of the Denims at Jo Ann's Fabrics are good choices as well.

if you sign up for their APP, they will send you coupons. 40% for only 1 yard, though.

Thank you Mike_StL , for much better explaining than I did.  ;D
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: R.J.Bruce on July 12, 2019, 08:54:09 PM
Some of the Denims at Jo Ann's Fabrics are good choices as well.

if you sign up for their APP, they will send you coupons. 40% for only 1 yard, though.

Thank you Mike_StL , for much better explaining than I did.  ;D

Thanks, Mike_StL

Every thing you said reinforces what I was thinking when I wrote the OP.

I'm still not sure if people have been misusing language by referring to a micrometer as a caliper; or are really bearing down on a caliper in order to compress the fabric.

And, like your father, the master machinists and tool and die makers that taught the apprentices at the shop where I worked would have literally screamed at us if we had abused a micrometer or vernier caliper in the way that Dutch Schoultz reccomends for someone to measure fabrics.

R.J.Bruce
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: hanshi on July 12, 2019, 10:15:27 PM
I don't own a micrometer but do own an excellent steel dial caliper.  I squeeze the jaws with both hands and my measurements are usually around what others measure with micrometer, usually within .0001" + or -.  Any measurement of thickness actually only gives one a measurement of the material compressed against the lands.  Groove compression is easily calculated as is land compression.  If your load performance meets your criteria for excellence, stay with it.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: OldMtnMan on July 12, 2019, 10:17:23 PM
Really? I've never notice that the word 'caliper' was used rather than 'micrometer', but when measuring fabric, a micrometer is to be use.   I wouldnt use an expensive one such as Starlett, a cheapo brand is recommended.

2nd post.

http://americanlongrifles.org/forum/index.php?topic=55120.0
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: nemovir on July 12, 2019, 10:27:02 PM
Really? I've never notice that the word 'caliper' was used rather than 'micrometer', but when measuring fabric, a micrometer is to be use.   I wouldnt use an expensive one such as Starlett, a cheapo brand is recommended.

2nd post.

http://americanlongrifles.org/forum/index.php?topic=55120.0

Well I'll be. Some people do use calipers rather than micrometers. 
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Darkhorse on July 12, 2019, 11:23:00 PM
I'm one of those old retired Master toolmakers that was referred to earlier in this thread. I've measured with about every measuring tool out there including Theodolites. My most used tool is my old Starrett dial calipers followed by my 0-1.0" Micrometers. I can measure patching material or a round ball and get the same measurement with either. I can measure a little closer with the micrometer because it is calibrated to .0001" where as the calipers are .001"
Here's the real secret to using precision measuring tools...your feel. To develop the feel requires hours and hours over years of measuring to build the muscle memory in your fingers where you just know when the jaws are "tight enough".
Another useful skill is knowing how to calibrate your tools and having the proper gauge to do it right.
I seldom use the clicker anymore but I feel most average guys measuring with a mic should use the clicker. It promotes accuracy and repeatability. That's why a micrometer has a clicker on it to start with.
I measured my work for so many years that I cannot build a rifle without those old starrett dial calipers being right there on the bench at all times.
As far as cheap tools go, I like mine to be a quality brand. But that's just me. Cheaper ones can work fine as long as you know how and when to calibrate your tools. So dial calipers or mic's just go  out there and do some measuring and you will be fine.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: rich pierce on July 13, 2019, 12:06:25 AM
If a shooter uses the same technique of measuring thickness of fabric they will be fine with whatever tool. I can feel the difference with my fingers between 0.010, 0.015, and 0.020” thick if the same weave.

It’s only when telling someone else what to use that technique matters. I personally use the clutch on my same micrometer.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: MuskratMike on July 13, 2019, 01:00:58 AM
Am I just under thinking this post? If you use the same material every time and you buy new patching material at the same store and it measures the same as it did last time does it really matter what instrument you use? Remember we are not sending projectiles to Mars, were just trying to keep then in a "tuna fish" cans size group at a reasonable distance. K.I.S.S.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: wattlebuster on July 13, 2019, 02:04:35 AM
Am I just under thinking this post? If you use the same material every time and you buy new patching material at the same store and it measures the same as it did last time does it really matter what instrument you use? Remember we are not sending projectiles to Mars, were just trying to keep then in a "tuna fish" cans size group at a reasonable distance. K.I.S.S.

Amen.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Herb on July 13, 2019, 02:28:04 AM
You must not read my stuff, every patching I use is measured with my 54 year old $5 Herters 1" micrometer, a crush measurement, not the ratchet.

Here I did some string cutting at 100 yards from bench rest, with my copy I made of Jim Bridger's Hawken.  You can hold down the CONTROL key and hit the + sign key to enlarge the picture.
(https://i.ibb.co/M87D2yY/Bridger-String-Cuts.jpg) (https://ibb.co/Q8MFb72)
This is 100 grains (weight-corrected measure) of Olde Eynsford 1 1/2F, my favorite powder in the .54.  .018 is the ratchet reading of the linen patching, and .008 is the crushed reading, which is what happens between the lands and the ball.
(https://i.ibb.co/DM9cbCK/String-Cut-OE1-F.jpg) (https://ibb.co/HPtw2zg)
This is 100 grains (W/M- weight corrected measure for THAT powder, OE 2F) and the same patching, which should read .018/,008.
(https://i.ibb.co/5G8NVKr/DSC01415.jpg) (https://ibb.co/S5nhpft)
On another topic, someone said  he was going to use OE 3F to work up a .54 elk load.  I have not shot decent groups with OE3F in but one .40 or .45 rifle (don't remember), and I cannot recommend it.  But OE2F and OE 1 1/2F are wonderful powders.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: HelmutKutz on July 13, 2019, 03:02:19 PM
My experience is textile printing which requires careful screen adjustment according to material thickness. The only reliable method to measure textile thickness is using a consistent thickness gauge. I use a Mitutoyo 7326S as it is enough accurate for field work. Textile is always measured in uncompressed state as the weave, thread count, thread spin style and many other variables produce inconsistencies.

I see many measure in store which does not give a true reading of measure thickness regardless of tool because the nature of the fibers and weave lay will change drastically when wetted with liquid or grease since neither are not compressible. I also warn before and I warn again, textile processing involves many chemical agents, most are corrosive and many are dangerous or toxic also. Regardless of material purchased it should aways be washed with a quality detergent that leaves no residue of perfume or softener and follow by two thorough rinse cycles in untreated low-mineral water. For highest consistency, textile should lay flat on rack of thin section or course screen to dry by evaporation. True measure should be done after washing and drying to remove all process and finishing agents which cause extreme variation in thickness prior to removal. Print pattern textile should be avoided for maximum consistency since the print medium itself can produce differential conditions in how the textile interacts with the bore and variations in spring and compression.
HK
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Longknife on July 13, 2019, 05:32:21 PM
I too use calipers to measure different thicknesses of materials but in reality it is not necessary at all!!.  When I sight in a rifle I take 3 or 4 different patch thicknesses with me. I recover the patches and if there are any signs of blow by or burn through I go to a thicker patch,,,,,Ed
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: hanshi on July 13, 2019, 11:42:24 PM
The important thing here is, I believe, consistency.  Long ago I used old t-shirts which can measure .010" and some even more.  I had blow by and holes in the patches; an op wad solved that problem.  It doesn't matter that much to me what a specific measurement is as long as it makes a good load and I measure the same way every time.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: MuskratMike on July 14, 2019, 01:55:11 AM
Mr. Hanshi:
You are a wise man.
 As I posted earlier we tend to way overthink things. This is a simple sport. Find what works for you and your specific rifle/pistol/smoothbore. Write it down and repeat as necessary. Quit worrying about what others do and find what works for you and your firearm.
Again the "Muskrat has spoken".
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Daryl on July 14, 2019, 05:17:25 AM
I have 3 'sets' of dial calipers &one 'set' of vernier calipers. The verniers agree with only one set of dial Calipers  those in a Hornady box  which happens to be in the middle of the other 2 sets.  Measuring 1 thou above the smallest measurement and 1 thou below the highest one.
My mic is a decent device which averages 4 thou smaller measurement than my "chosen" Hornady set.
If I crank down on the barrel, my mic will show 12 oz. Denim as measuring .013".  The calipers have that material as .030", crushed as hard as I can between finger and thumb. My mic measures it at .025".
Now, what do you get for a measure 12oz. Denim with your tools of choice? The 14oz. went .034" for me- calipers, crushed.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: HelmutKutz on July 14, 2019, 01:12:09 PM
I have 3 'sets' of dial calipers &one 'set' of vernier calipers. The verniers agree with only one set of dial Calipers  those in a Hornady box  which happens to be in the middle of the other 2 sets.  Measuring 1 thou above the smallest measurement and 1 thou below the highest one.
My mic is a decent device which averages 4 thou smaller measurement than my "chosen" Hornady set.
If I crank down on the barrel, my mic will show 12 oz. Denim as measuring .013".  The calipers have that material as .030", crushed as hard as I can between finger and thumb. My mic measures it at .025".
Now, what do you get for a measure 12oz. Denim with your tools of choice? The 14oz. went .034" for me- calipers, crushed.

Calipers and micrometers are usually easy to calibrate using various gauges of known thickness. First and most important is checking jaws for damage and parallel. Typical calibration of non-critical measure device is done in-house in industry. The procedure requires three check and set at minimum, mid and maximum ranges then test for repeat of readings within tolerance capabilities of the measure device. For common 0-25mm micrometer with ±0,001mm tolerance the test gauges are ranged 0,005mm; 10,0mm and 20,0mm. The exact gauge thickness/length does not matter as long as gauges cover the minimum, mid and maximum spectrum of the measure device range. When using micrometer measure should always be taken using the friction nut to ensure consistent pressure between anvil and spindle and avoid causing deflection in beam and wear on threads. When using vernier or dial caliper where clamp should be applied using only thumb wheel and sufficient only to stoppage of jaw movement as both jaws and beam can be easily distorted resulting in permanent erratic measure. When calibrated the measure device must produce consistent results in repeated measure of gauges within the listed tolerance of device. For micrometer example above, the 0,005mm gauge should show consistent measure of 0,004-0,006mm and same for other gauges. If measure device does not hold consistent measure to rated tolerance, it should be repaired or replaced.

As I explained above, the proper measure of textile is in it's uncompressed state using a measure device such as Mitutoyo 7326S where consistent clamp force is applied by the internal spring.
(https://i.ibb.co/Bsjbb4x/Thickness-gauge.jpg) (https://imgbb.com/)

If you wish to take a fiber compression or springback measure, the proper method is to use a known weight to compress textile for a given time. Typical standard testing is 5kg per one square cm using stainless steel cylinder weight standing on end with single layer of textile flattened over stainless steel plate. Let stand 2 hours remove weight and immediately measure thickness at center of depression, repeat thickness measure two hours later to obtain springback. Again, you may use what you have available at home to conduct measurements, the only critical factor is that all measures are conducted with same method and consistency.
HK
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: R.J.Bruce on July 14, 2019, 04:03:54 PM
Thank you!! Thank you!! Thank you!!   to HelmutKutz

Your two posts on this topic are exactly the points that I had in the back of my mind when I wrote the OP.

Consistency is the key, and it had seemed to me that consistency would be easier to achieve with a 0"-1" micrometer, as opposed to a 0"-6" dial caliper.

Just my old machinists training kicking in.

If one of those old machinists overseeing the training program that I was in had witnessed me squeezing the jaws of my calipers together in the way that Daryl, and others, have described; they would at least yelled at me, if not actually grabbed it from my hands before I could damage it.

We were taught to NEVER use a set of calipers in that way.

Of course, measuring materials almost exclusively made of hard metals, there was no need to use a caliper in that fashion.

By squeezing a caliper as described, the risk of bending the jaws is greatly increased over normal usage.

To those that have suggested that I was making things too complicated, that was not my intention.

Back in the 70's when I first started shooting, I just cut up old t-shirts and blue jeans; using what I had until I found something that worked.

I didn't measure the thickness of anything!!

It does not matter what tool one uses. As long as the tool remains accurate, and it is used in the same way every time that the user goes out to purchase fabric.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Daryl on July 14, 2019, 08:10:58 PM
All of my measuring devices measure hard objects with EXACTLY the same result - ie: measurement, whether done by 2 micrometers or my 4 sets of calipers including the vernier's
which require me to use a magnifier to read.
Measuring cloth is subjective and must be measured with heavy compression to simulate the lands of the barrel - the same each time, using the same technique.

Just for a lark, I measured my 12oz. denim that gives/has given me the best accuracy in my 14 bore since 1986.  Compressed hard as described it's .030". Not compressed, .035". In the mic, compressed by
the ratchet, is .025". Taylor's Sterret Mic. measures with it's softer ratchet setting, at .028".  With my mic, the barrel cranked down like Herb does, which I feel is abusing the mic, I get .0035"
- yes - 3 1/2 thou. Now - you tell me what is the correct measurement. Subjective and different for everyone no matter what system they use.
 This material is used with a .682" dead soft lead ball of 482gr. The bore of the rifle measures exactly .690", with grooves of .012". Thus,  the mic. measurement, when added to the ball dia.
I get .025 + .025"+ .682" = .732". I make that out to mean .732" - .714"(groove dia) = .018" which is .009" compression in the bottom of each groove. Add .012" to that for each  land compression.  Now, if we use the compressed caliper measurement, we get .752" - .714 = .038" which is .019" compression in the bottom of each groove. Note, this is a VERY tight load, but
it is an amazingly accurate one. I have tested pretty much all manner of looser combinations, and while some do OK to 50yards, they lack the consistency to work well from 100yds. out to 200. I do love ringing the 14" x 16" 200 meter gong each shot. I think this barrel prefers this heavy patching, due to the reamer marks on the lands. It has always made me patch heavily.
 
The round ball Bench Rest shooters are using virtually identical compression figures, but are likely using false muzzles, oversized pure lead balls and Teflon patching. They have to clean every shot. My bore is cleaned every time I load it and yes- the rifle's hickory rod is used. I retired the hickory rod this spring after 33 years of use (only cracked it once then CA repaired for 3 years) and now have a nice Osage rod for it, curtsy of Taylor for making it and Ron, for the beautiful wood. Getting this combination started without cutting the patch and actually allowing multiple shots from the same patches, requires that you WANT to get it started. It also necessitates a smoothly crowned muzzle, with no machined corners like most barrels come with.

I feel the cloth must have enough compression in the bottoms of the grooves to seal the powder gasses beneath the ball, or the patch will burn through if
enough flame pass by it. This will alter/vary the pressure thus velocity, causing accuracy problems as well as blasting out different sides of the patched ball as it leaves the muzzle.
Thus, we tend towards tighter combinations to obtain better accuracy. We and others who load this way obtain improved accuracy and at rendezvous, spend much time in the winner's
circle.


(https://i.ibb.co/xD06cxf/muzzlecrown14bore001-zpsfebb8697.jpg) (https://ibb.co/G0LR1zt)
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: R.J.Bruce on July 14, 2019, 09:22:18 PM
A big thank you to Daryl, Helmut, and all those who have responded!!

I have nothing but the greatest respect to all of those experienced men and women who so freely share their hard won knowledge here on ALR.

ALR and Scoutrifle.org are two of the few places online where a person can ask for, and receive, a no-bull truthful answer to a question.

This site is a Godsend for anyone seeking to further their muzzleloading education.

Especially for someone like myself who knows a little, but not enough!!

R.J.Bruce
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: hanshi on July 14, 2019, 11:41:17 PM
Interesting info, Daryl.  Using my caliper to measure "blue jean" denim give me the same measurement of .025".  Admittedly, I can't squeeze that hard due to rheumatoid arthritis, but I can keep it pretty consistent.  Measuring patch thickness is definitely a subjective process.  Textiles can be compressed to ridiculous thinness and BP shooters avoid that.  If it ain't broke, don't fix it, or, what works, works.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Darkhorse on July 15, 2019, 02:15:30 AM
I don't measure patching material much anymore. I find the material I want and measure it once. If it's what I need I'll buy 10 yards or so from the same bolt. After that there's no need to measure for a long time.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: MuskratMike on July 15, 2019, 03:28:27 AM
10 yards? How much shooting do you do? That's enough material to make several thousand patches. However that is good advise. Just because you found it today doesn't mean you will find it next time.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Darkhorse on July 15, 2019, 05:40:42 AM
LOL! I don't shoot enough anymore to use up 10 yards that's for sure. I'm 66 now and go more for quality practice sessions than quantity. But I've been doing this since 1976 and when I was younger I was driven to excell, both on the firing line and the deer woods. There is no way to accurately measure how many yards of ticking I used up in those years. I do remember buying a couple of nearly full bolts of fabric a couple of times. I want my patching to come from the same lot if at all possible that way I know it's all the same.
I bought my powder the same way, a full case at a time each of 2f and 3f. Same thing, same lot, same powder and burn characteristics.

But it only makes sense, at least to me, to buy enough material of the same lot to last a few years. In the long run patch material is cheap.
I keep thinking "what if they stop making ticking of 100% cotton and put a bunch of nylon in the product?" Well if they do it won't stop me from shooting and that's a fact.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Daryl on July 15, 2019, 07:15:21 PM
10 yards? How much shooting do you do? That's enough material to make several thousand patches. However that is good advise. Just because you found it today doesn't mean you will find it next time.

10 yards of 12oz. will last a couple years, sometimes more, as I only shoot it in the .69.

One year I only shot that rifle, no others.

Close range shooting, out to 50 yards was all done with 82gr. 2F GOEX
and longer range shooting, out to 200yards was done with 165gr. 2F. That year, I went through 25 pounds of powder but I do not remember how many yards of material I used.
This is a 5-shot 25 yard offhand target I produced, shooting against Taylor in a little contest we had. It is one of the few times I have beaten him shooting on paper - or on the plates.
For this match (picture at bottom), I used a .677" WW ball patched with thicker 14 oz. denim.

Practice certainly helps and a lot of practice helps more. I used that rifle in 6 matches at Hefley that year, winning 5 of them. I only placed in the middle of the bunch, in the long range match
shooting against ctg. guns with aperture sights. I was quite happy with that result as well.


(https://i.ibb.co/whHdQg4/25-yard-group-14-bore-rifle.jpg) (https://ibb.co/5hD1j4L)
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: D. Taylor Sapergia on July 18, 2019, 07:09:05 PM
Here's my thoughts on measuring patch material.

When you seat a patched ball into the muzzle of your rifle, the material is squeezed extremely hard between the lead and the bore.  The patch material MUST be compressed at the bottoms of the grooves as well as the lands, otherwise blow-by will occur and accuracy loss, not to mention the real possibility of igniting the patch and causing a fire.

When one knows the bore diameter, groove diameter and diameter of the lead ball, it is easy to calculate the patch thickness required to give a good seal in the bottoms of the grooves...simple math.

Knowing how hard the material will be compressed, squeezing the material as hard as you can in a set of calipers (Vernier) using your thumb and fingers of both hands, is the only way you can accurately assess the patch's thickness once compressed.  The anvil(s) on a micrometer are too wide to simulate the lands of a rifle bore, so the Vernier's is the tool I use.

Works for me and those I shoot with.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Daryl on July 18, 2019, 09:12:10 PM
Further to Taylor's post above, when using the mic and cranking on the barrel, the force generated due to the fine thread is so extreme as to produce #'s that are meaningless.

The 12 oz. denim I spoke of, measuring .030" with squeezed calipers, I can actually get down to .005" with my mic. by really cranking on the barrel.

Some of the guys on this forum cannot load a ball .005" under bore size with a 10oz. denim I measure at .022" to .0225" using my calipers. I just cranking down on that material with my
mic and got .001". That's 1  thousandth of an inch.  So - what is it, .001" or .022/5?  Calipers and mic, both v/hard compressed.

I believe you should find a material you can load with, that shoots great and does not allow fouling to build in the bore- thus never needs wiping while shooting. That is my criteria. What the material measures with whatever tool you use, is immaterial (yeah - pun intended), but if it works for you, stick with it.  I know, that if a material measures .022" with my dial calipers, it will shoot
well in most of my guns.

Joanne's fabrics sells denim listed in ounce weights.  I have found that 8oz. will shoot fairly well in guns with square rifling, when using a (dead soft) ball .005" smaller than bore size.
 If using a .010" undersized ball, 10oz will likely shoot better and be more accurate(with either ball).  With rounded (deeper) rifling you will likely find you need a .005" undersized ball AND 10oz denim.

The light canvas that measures .022" with my calipers (compressed) loads harder for me with a .005" undersized ball than the 10oz denim I have, but - it shoots better and seals better in my GETZ .50 bl. I can still squeeze that down to whatever I want with my mic. abusing that instrument totally.
with rounded rifling.

To load tight combinations, which I find shoot best, requires a smoothly crowned barrel. The better this polishing and rounding of the corners cut by the bl. maker's machine, the easier loading you will have with ANY combination.

DaveC makes a tool to cut this crown.

(https://i.ibb.co/WkkGK7S/Dave-Crysalli-English-Rifle-11.jpg) (https://ibb.co/5rrGcCq)

Using different grades of emery or wet/dry paper and the end of your thumb, you can 'grind' this crown yourself. Some minor modicum of skill is required. Rotating the barrel frequently will
make this crown perfectly even.

(https://i.ibb.co/0F075w1/PB141918-zpsbd7b72c5.jpg) (https://ibb.co/Nm0vR4f)
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: hanshi on July 18, 2019, 10:42:49 PM
It's been my thought that a caliper is a good "stand-in" for the grooves, as far as compression is concerned.  By the way, what's the weight of blue jean denim?
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: Daryl on July 19, 2019, 06:22:56 PM
A lot of the blue jeans I have worn in the past (before - comfort fit  ;D) had .020" to .022" material as I measured it, compressed with calipers. From old jeans, the material from the back of the calf and back of the thigh areas was all that was usable as patch material, as the rest was too worn and inconsistent.
The last pair I had, actually had 12oz. denim, which I measure at .030" with calipers compressed and .025" with the ratchet on my mic.
Title: Re: Measuring patch material, or pre-cut patch thickness
Post by: hanshi on July 19, 2019, 10:28:19 PM
Thanks, Daryl.