Ruger Forum banner

1 - 20 of 21 Posts

·
Banned
Joined
·
269 Posts
Discussion Starter · #1 ·
has anyone made there own caliper calibration block to check there digital or dial calipers?

or know where to buy a cheap one?

I just would like to see if my calipers are reading the correct measurements.
 

·
Registered
Joined
·
484 Posts
Picked a digital on online for 20$ shipping included works well and compared it to one from work readings were the same.
 

·
Banned
Joined
·
269 Posts
Discussion Starter · #6 ·
exactly

I think he was referring to a guage block, to check the accuracy of the caliper he has...:D
The frankford arsenal digital calipers I have, have no reference point. No numbers on the scale anywhere.

I was going to use a gauge block, and be sure the 0 I set, will measure up to lets say a 1 inch gauge block. give or take + - a few thousandths.

hopefully its right on.

It will help me set my 0 at least.
 

·
Banned
Joined
·
269 Posts
Discussion Starter · #7 ·
I usually just use a LE Wilson case gauge, and trim on the brass trimmer visually,

if the brass sticks above the gauge, I just trim enough where the case sits flush inside the gauge.

but every now and then I like to double check with the caliper.

if the brass doesn't fit in the case gauge easily, I throw it out.
 

·
Banned
Joined
·
269 Posts
Discussion Starter · #9 ·
Could have got a whole set off eBay for $80. But I only need one, $20. Calibrated for 2 inches. Peace of mind that my digital caliper is not if by twenty thousandths. If you don't know, you measure the block and in this case for a 2 inch block the caliper reads 2.000. Works great. I would do the same for a mechanical caliper, but the digital one is easier to read.
 

Attachments

·
Retired Moderator & Gunsmith
Joined
·
17,055 Posts
I made my own on my mini-lathe out of round brass stock. I have a 1" that was "calibrated" with a micrometer accurate to .0001". After checking several of my dial and digital calipers, I found they were all within .001" so it sits in one of my caliper boxes collecting dust.
 

·
Banned
Joined
·
269 Posts
Discussion Starter · #13 ·
calibrated

I made my own on my mini-lathe out of round brass stock. I have a 1" that was "calibrated" with a micrometer accurate to .0001". After checking several of my dial and digital calipers, I found they were all within .001" so it sits in one of my caliper boxes collecting dust.
I know, how do you calibrate a piece of metal? haha. believe it or not there are people who get paid to check that gauges like these are calibrated. the date code in the box it came in states it needs calibrated in another year. I guess I will check with my calipers to make sure the block is still 2 inches.

I just dont wanna be measuring and my battery goes low and starts giving me inaccurate readings, or set the 0 wrong.

where did you get a mini-lathe? if you dont mind me asking.
 

·
Banned
Joined
·
269 Posts
Discussion Starter · #15 ·
Calibration spec sheet

I did not shoot holes in the spec sheet. Haha. On the calibration sheet that came with the gauge it was checked for nominal length, center deviation, parallelism, given a ID number, and given a grade by a chief inspector.
 

Attachments

·
Banned
Joined
·
269 Posts
Discussion Starter · #16 · (Edited)
I learned my digital caliper works. And when I go to measure I'm getting correct measurements. If my digital caliper fails to read 2 inches on a calibrated gauge block I know something's wrong with my caliper. That's really the only way to check a caliper like I have correctly, with a gauge block. If you do any manufacturing process, while setting up your work area for measurements you are always suppose to make sure you equipment is working and functioning correctly, especially with precise instrumentation such as this. Always. Without a reference point the caliper is useless.
 

·
Retired Moderator & Gunsmith
Joined
·
17,055 Posts
RugerAR,
how do you calibrate a piece of metal?
I cut off a liberal section of 1/2" brass rod stock ... a tad over 1" long. I then squared one end and smoothed it. From there I pulled the stock out of the lathe and measured it. I don't remember exactly what the length but it was several thousandths too long. The dial on my cutter is calibrated in .001" increments so I cut the rough end down where the rod was about .001" too long then dressed the end with a jeweler's file until the rod measured exactly 1", using a micrometer with a .0001" resolution. This took several tries to get it exactly 1". Worst case ... it may be off .0001" .... about 10x more accurate than a typical dial or digital caliper can resolve.

I have four digital calipers ... a Chinese cheapie 4" from Harbor freight (under $20), a 6" Mitutoyo (about $120) and a 8" Swedish made with a computer port ($250+). My most recent purchase was from Grizzly ... a digital that reads in decimal .001" increments and fractional inches in 1/64" increments ... plus metric. Pretty handy when you pick up a drill bit or a piece of stock and want to know the fractional inch size without having to use a conversion table or a calculator. Here's the funny part ... the cheapo Harbor Freight caliper is just as accurate as the others ... in fact there is no accuracy difference in any of them, but the more expensive units are made stronger.

I just dont wanna be measuring and my battery goes low and starts giving me inaccurate readings, or set the 0 wrong.
I haven't replaced a battery on the new Grizzly yet. It has a feature where the display will flash when the battery needs to be replaced, As for the others, the digital display will get dim long before there is any change in accuracy. Matter of fact, I was using one of my digitals when the battery died and it maintained accuracy up to the dying gasp. Batteries are cheap if you know where to get them ... $7.95 each at Wal-Mart or you can get a card with 10 batteries for $5.95 on the Internet or in some stores. One of the venders at our local gun shows sells the 10 battery card for 10 bucks ... which is still a good deal ... a buck a year.

I also have a mitt full of dial calipers (at least 5) that rarely get used. The only one that has problems is an expensive 6" Fowler ... made in Germany. I bought it at least 30 years ago and it has been used a lot and probably dropped a few times. The internal gears have developed some hysteresis so the needle no longer maintains a good zero. I should throw it away but I'm too frugal. In this day and age, there's no reason to use a dial caliper when you can get a Harbor Freight digital unit for less than 20 bucks. They even come with a spare battery. All the digitals have a feature that is great for reloading applications .... works much like tare weight on a scale. You can place a brass case or bullet in the caliper, slide the jaws shut then press the "zero" button. From there, you can measure a batch of bullets or brass cases where the digital display will indicate how many thousands short (- .00x) or long (+.00x) your cases are compared to the sample case. Further, a press of a button and you can get measurements in metric units. Can't do that with a dial caliper. Yes, I know ... some people just don't trust electronics or complain about a dead battery. Simple solution ... keep a spare battery in your caliper box ... it only take a few seconds to change them ... maybe once a year. Dial calipers have an exposed gear track that doesn't deal well with dirt, tumbler media, metal filings, or any other crud. They are also much more sensitive to shock ... being dropped or just pushing the jaws shut too fast. The digital calipers do NOT have a gear track so they are pretty immune to crud and hold up much better when dropped or abused.

When I had my gunsmith shop, I owned a WWII vintage 48" bed Bridgeport lathe ... super precision, leaps tall building with a single bound ... but it got sold along with all my other gunsmith tools when I went out of business. About 4 years ago I decided to get a mini-lathe so I could make stuff for my reloading equipment ... such as pilots for my case trimmer, powder dies for my Dillon RL550 press and many more things. I also make cylinder throat pin gauges for all calibers of revolvers. I bought my mini-lathe from Grizzly ... not nearly the quality or size of my old Bridgeport but good enough for hobby stuff. Here's a link: Shop our G0765 - 7" X 14" Variable-Speed Benchtop Lathe at Grizzly.com
 

·
Banned
Joined
·
3,167 Posts
When I was managing a design fab and build engineering firm, the company bought me a plethora of equipment that I still use today for personal projects. I have a large box of very expensive metal blocks of various sizes sitting on a shelf in my shop. Maybe 10yrs since I have touched it.

For caliper validation, I use my dummy cases that I cut for setting up my case trimmer. I engraved their lengths on the side, if my calipers ever don't read true, they go in the trash. Two of my calipers I use daily are 15-20yrs old, and I use a dial probably weekly or bi-weekly that's over 30yrs old. I have only ever had two sets of calipers fail on me. One I dropped off of the top of a 65ft tank while working up top, stripped part of the internal gear, and one I left on my bench top when running the tig just a bit too close, and I warped the caliper shaft.

Point is - more likely than not, you wasted $20. I get more productivity and benefit out of $20 worth of toilet paper than I do out of my gauge blocks for reloading calipers.
 
1 - 20 of 21 Posts
Top