Marking of Tensile Test Specimen

S

Sorin

So...I am looking for something to mark our tensile test specimen. I've searched and I am unable to find a satisfactory device.
The one that was the closest is Tensilmark from Tensilkut,
The description (from their website):
"The Tensilmark is a compact, freestanding unit designed to scribe gauge marks on prepared flat or round specimens made of most machineable materials. The marks are accurately produced on 1? or 2? centers, within ASTM tolerances of +.002?. A floating steel bar contains two hardened steel scribe pins for rapid and consistent elongation marks on specimens by unskilled technicians."

The problem is that they:
-are unable to provide a short video of the process;
-do not provide a certificate of calibration for the 1.000"+/- 0.002 distance;
-pins are not replaceable.

Most of the devices I found are punching devices and I am not keen at all about the idea of punching test specimens.

Anyone know of a device that:

1.Have replaceable pins/markers.
2.Can be calibrated.
3.Have floating pins/markers and not a punching system.

Materials are up to 300 Ksi UT, specimen are round, marking length is 1.000" +/-0.002.

Thank you in advance.
 

Marc

Fully vaccinated are you?
Leader
Another quick "Bump". My Thanks in advance to anyone who can help with this one.
 
G

Gmzita

Try Tinius Olsen Center Punch - variety of sizes available, separate punch points can be purchased and the unit can be sent back to the Pennsylvania facility for certification. I tried to copy and paste the link for their site - but I still do not have enough postings at Elsmar so I am not allowed. Go to tiniusolsen.com or just use a search engine and type in Tinius Olsen Center Punch to get a direct link or contact their Customer Service Department at 215-675-7100 x 100.

Added by moderator:
(broken link removed)
 
Last edited by a moderator:

Wes Bucey

Prophet of Profit
Just to add to the discussion:
When I was in the machining business, we simply prepared the coupons [specimens] to length and diameter, delivered them to a metallurgy lab and they did everything else. That was 12 years ago. It seems to me a phone call to several such metallurgy labs would result in some leads as to the current best solution to your query.
 

ChemEShellE

Registered
Instron sells small plastic marking rulers for $35, but the paint gets really messy over time and acetone strips the guidelines. I'm looking for a metal machined version that can be certified by our calibration guys. Found an extra-expensive option that uses reflective tape (from universalgripco) but I feel like this would be fairly easy to make in house. Did anyone find something more suitable?
 

Matt Swartwood

Starting to get Involved
Hello. We made our own indention gage. The handle (which is lightly tapped by hammer to make indentions in the tensile specimen) can be moved from one side to the other and the indention cones can be replaced. One side measures 1.000 and the other 2.000. We then use calipers with conical pins (which are also replaceable) to measure the distance between indentions.

Do you have a requirement for +/- .002 or is that what you set internally? That seems pretty tight for this type of tool. We calibrate ours with an optical comparator and have given our machine shop (who made it) a tolerance of +/- .01. We then have a very tight tolerance on the caliper accuracy and repeatability.

 

Wes Bucey

Prophet of Profit
So...I am looking for something to mark our tensile test specimen. I've searched and I am unable to find a satisfactory device.
The one that was the closest is Tensilmark from Tensilkut,
The description (from their website):
"The Tensilmark is a compact, freestanding unit designed to scribe gauge marks on prepared flat or round specimens made of most machineable materials. The marks are accurately produced on 1? or 2? centers, within ASTM tolerances of +.002?. A floating steel bar contains two hardened steel scribe pins for rapid and consistent elongation marks on specimens by unskilled technicians."

The problem is that they:
-are unable to provide a short video of the process;
-do not provide a certificate of calibration for the 1.000"+/- 0.002 distance;
-pins are not replaceable.

Most of the devices I found are punching devices and I am not keen at all about the idea of punching test specimens.

Anyone know of a device that:

1.Have replaceable pins/markers.
2.Can be calibrated.
3.Have floating pins/markers and not a punching system.

Materials are up to 300 Ksi UT, specimen are round, marking length is 1.000" +/-0.002.

Thank you in advance.
So, full disclosure; I no longer own or operate a Precision Machining company, I am strictly a consultant in semi retirement, dealing with a variety of for profit and nonprofit organizations.

Each year, I see dozens of operations. I have seen several with highly accurate fiber laser marking devices.

They aren't cheap, so, unless you're preparing hundreds of test "coupons," it would make economic sense to locate a company using one in their own operation and work out an outsourcing deal for that company to mark your coupons.

Similarly, I am always leery of hand held caliper readings and subsequent hand written or keyed documentation

Even 25 years ago, my shops used laser micrometers accurate to 0.0001 inch. The readings were directly transmitted to our computer and instantly available to mill which produced the metal, to heat treaters, customers, and available to any concerned party for a minimum of five years.

Calibration should be easy peasy with appropriate certification.
 
Top Bottom