Measuring patch material, or pre-cut patch thickness

[R.J.Bruce]

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

[nemovir]

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.

[R.J.Bruce]

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

[nemovir]

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.

[Mike_StL]

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.

[nemovir]

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. 

[R.J.Bruce]

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. 

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

[hanshi]

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.

[OldMtnMan]

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

[nemovir]

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. 

[Darkhorse]

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.

[rich pierce]

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.

[MuskratMike]

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.

[wattlebuster]

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.

[Herb]

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.

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.

This is 100 grains (W/M- weight corrected measure for THAT powder, OE 2F) and the same patching, which should read .018/,008.

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.

[HelmutKutz]

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

[Longknife]

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

[hanshi]

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.

[MuskratMike]

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".

[Daryl]

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.

[HelmutKutz]

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.


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

[R.J.Bruce]

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.

[Daryl]

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.

[R.J.Bruce]

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

[hanshi]

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.