Portable hardness tester PTC Model 16 - opinions wanted

[JV Knives]

Hi friends,

I am on the lookout for a good deal on hardness testing unit that I can afford. I saw a style that I was not familiar with on a local swap sight. Its called the PTC Model 16 and runs about $1100 new but can get this one sub-$300. Anyone have experience with these units or this style? My interests of course are assessing final blade hardness (range 58-64 ish Rc). Gonna link the amazon website here and I think thats's OK with the rules (?) please delete if I am incorrect.

https://www.amazon.com/PTC-Steel-Hardness-Tester-Portable/dp/B01FYJMMMA

Thanks!
John
JV Knives

 

[Stacy E. Apelt - Bladesmith]

Not what you want for knives. Save your money.

 

[JV Knives]

Not what you want for knives. Save your money.

10-4...thanks Stacy.

 

[fitzo]

Oops, edited:

I have a PTC but not your unit. It's a good company is all I can attest to.

 

[DeadboxHero]

Sorry, but I disagree with Stacy.

I have used one for 35 years and had it compared more than once to a calibrated Wilson. You need a really stiff table on a drill press and it will get you within a point, repeatedly. There were no imports when I first purchased, no eBay, etc, to buy a used Wilson. So, I went with what I could afford and what has a long proven record on the toolroom floor. I have never been unhappy with the unit, and never been willing to shell out again for an import bench unit. YMMV

If you can afford the bench unit, take the trime to save the extra bux and get that. If not, this will work.

No disrespect Fitzo but $1100 for a punch, tiny microscope with maglite illumination and a calibration block is highway robbery. That's about the same price as a bench top tester.

The PTC model 316 doesn't even generate numbers. You just eyeball the indentation and qualitatively compare it to the calibrated block.

What?

I wouldn't take anybody's HRC values seriously if they used that method.

I'm sure it works great for the tool shop floor when you just need to see if something is hard or soft or hard and "harderer" almost like a file.

Except $1100!


Well, "Hard" Pass.

Imho I wouldn't let a friend buy one.

Ymmv

 

[fitzo]

No disrespect Fitzo but $1100 for a punch, tiny microscope with maglite illumination and a calibration block is highway robbery. That's about the same price as a bench top tester.

The PTC model 316 doesn't even generate numbers. You just eyeball the indentation and qualitatively compare it to the calibrated block.

What?

I wouldn't take anybody's HRC values seriously if they used that method.

I'm sure it works great for the tool shop floor when you just need to see if something is hard or soft or hard and "harderer" almost like a file.

Except $1100!


Well, "Hard" Pass.

Imho I wouldn't let a friend buy one.

Ymmv

Sorry, DeadboxHero You caught my first post. I had the wrong tester in mind at first, so you have me with egg on my face. I agree with Stacy's and your opinions completely. Not appropriate. I'd argue a bit about the model I have, though.

I bought one of these prior to the days of cheap Wilson clones or eBay. PTC Model 415C. It has performed handsomely. This link is not allowed, so look quick.

https://www.ptc1.com/415c-steel-hardness

 

[ak650]

Will be interesting to see any other ideas/experiences on this. I've always used the Japanese files for machine shop type work. Now that I've been bit by the knife bug, I'd like something more accurate and repeatable. I've looked at the various PTC brand instruments, but there are just way too many variables at play there to get repeatable performance IMO. And it looks like testers that use the Leeb method are out, as they're no bueno for small and/or thin test samples. Sure kinda looking like a Wilson, or a good quality clone are about it, especially if one is going to be dropping in the neighborhood of $1000.

 

[fitzo]

Will be interesting to see any other ideas/experiences on this. I've always used the Japanese files for machine shop type work. Now that I've been bit by the knife bug, I'd like something more accurate and repeatable. I've looked at the various PTC brand instruments, but there are just way too many variables at play there to get repeatable performance IMO. And it looks like testers that use the Leeb method are out, as they're no bueno for small and/or thin test samples. Sure kinda looking like a Wilson, or a good quality clone are about it, especially if one is going to be dropping in the neighborhood of $1000.

I agree about variables you will not have with a benchtop machine. Installation items like a rigid table 90* to the tester axis and rigidity of the entire unit all come into play. A pipe jammed under the table helps any lower movement. A sloppy spindle probably would be bad. Another important aspect is human and feel. One develops a feel for the 415 and both accuracy and precision go up. My first gig out of college was a research flunky for a carbide company. Used Wilsons every day for a year. Would love to have even one of those ancient beasts now today. point is, I was thus somewhat skeptical about this toolroom device but couldn't find a used Wilson in pre-internet days and limited resources. So I bought one and asked my machinist mentors to check it out. Being geeks, they trotted it over to the Metrology fellows in Engineering Research (big company) who were all of course more than happy to drop what they were doing and f around with the new toy. LOL They came back, "Hey, not too bad for what it is. Compares well to our machine. bring it back periodically so we can check it out. We're curious." So, they were happy, I was happy, and it served my needs for years of productivity. I sent it back once just for a checkup and it passed muster just fine.
Is it as good as a mid-range import bench machine? I doubt it. And certainly not anything like a high end unit. But grizzly has quit carrying the imports and if the import supply dries up it will be like those days when I was the only maker I knew with ANY kind of tester other than "a new triangle file" and "just the right shade of pale yellow on the edge" for temper. And then maybe this will be of use again. And, thus, my mention.

Regardless the machine, quality control of home heat treating is benefitted by accurate testing of hardness.

 

[ak650]

I agree about variables you will not have with a benchtop machine. Installation items like a rigid table 90* to the tester axis and rigidity of the entire unit all come into play. A pipe jammed under the table helps any lower movement. A sloppy spindle probably would be bad. Another important aspect is human and feel. One develops a feel for the 415 and both accuracy and precision go up. My first gig out of college was a research flunky for a carbide company. Used Wilsons every day for a year. Would love to have even one of those ancient beasts now today. point is, I was thus somewhat skeptical about this toolroom device but couldn't find a used Wilson in pre-internet days and limited resources. So I bought one and asked my machinist mentors to check it out. Being geeks, they trotted it over to the Metrology fellows in Engineering Research (big company) who were all of course more than happy to drop what they were doing and f around with the new toy. LOL They came back, "Hey, not too bad for what it is. Compares well to our machine. bring it back periodically so we can check it out. We're curious." So, they were happy, I was happy, and it served my needs for years of productivity. I sent it back once just for a checkup and it passed muster just fine.
Is it as good as a mid-range import bench machine? I doubt it. And certainly not anything like a high end unit. But grizzly has quit carrying the imports and if the import supply dries up it will be like those days when I was the only maker I knew with ANY kind of tester other than "a new triangle file" and "just the right shade of pale yellow on the edge" for temper. And then maybe this will be of use again. And, thus, my mention.

Regardless the machine, quality control of home heat treating is benefitted by accurate testing of hardness.

I get that completely, and think they've got to be a big leap forward from a set of hardness files. ( I was a Metrology lab nerd 40 years ago, thanks to Uncle Sam ) I just wish they were priced more realistically. The PTC #415C retails for $1395! At that level, may as well camp out on eBay for a while, and snatch up a Wilson or equivalent. What I find odd, is that PTC lists both the #316( the center punch/optical handheld ) and the #415C ( drill press version ) at the same accuracy of + or - 1.5 points.

 

[fitzo]

I get that completely, and think they've got to be a big leap forward from a set of hardness files. ( I was a Metrology lab nerd 40 years ago, thanks to Uncle Sam ) I just wish they were priced more realistically. The PTC #415C retails for $1395! At that level, may as well camp out on eBay for a while, and snatch up a Wilson or equivalent. What I find odd, is that PTC lists both the #316( the center punch/optical handheld ) and the #415C ( drill press version ) at the same accuracy of + or - 1.5 points.

I think that sounds like the wise path, especially if you have avenues for repair/restore/recalibaration.

 

[JV Knives]

Thanks guys for all the opinions! Love to hear how others in my boat are carrying on think I’ll hold out for something more repeatable after all the comments. I already have hardness files which is a system that I’m not liking…no reason to add another regret. As is often the case in this game, buy once and cry once probably applies.

Best,
John

 

[ak650]

There's also the Ames line of portable/handheld testers. Still made, but again.....sticker shock! $3K+. They claim a + or - 1 point spec. Anyone have experience with them? With a mechanical/analog meter movement, I can't imagine being able to get considerably closer than that. Even the vaunted Wilson 1JR, 2JR, etc is an analog meter movement, with a minimum graduation of 1 point, and no mirror to help minimize parallax error. So any measurement less than a whole Rockwell point is subject to user interpretation. It's curious they didn't put half point tick marks between the graduations.

 

[fitzo]

There's also the Ames line of portable/handheld testers. Still made, but again.....sticker shock! $3K+. They claim a + or - 1 point spec. Anyone have experience with them? With a mechanical/analog meter movement, I can't imagine being able to get considerably closer than that. Even the vaunted Wilson 1JR, 2JR, etc is an analog meter movement, with a minimum graduation of 1 point, and no mirror to help minimize parallax error. So any measurement less than a whole Rockwell point is subject to user interpretation. It's curious they didn't put half point tick marks between the graduations.

I think the question would be whether ANY decimal fraction has any accuracy at all, or whether the system error means zero significant figures (no fractional number) is appropriate reporting?

 

[DeadboxHero]

I think the question would be whether ANY decimal fraction has any accuracy at all, or whether the system error means zero significant figures (no fractional number) is appropriate reporting?

It's a part of the standard test method for rockwell hardness testing.

ASTM E18-22

Before the year 2000 the United States was lagging behind in the accuracy and quality of hardness testing compared to Japan and Europe due to a lack of standardization and universal best practices.

In 1991 the American Society of Testing and Materials (ASTM) requested the help and direction of the National Institute of Science and Technology (NIST) to develop a national standard for Rockwell Hardness testing.

It took seven years and wasn't rolled out fully until the year 2000 with E18-00.

Standard reference materials (SRM) with traceability to the NIST master blocks and indenters. That way everybody can be on the same page.

The harder blocks have a 0.5rc tolerance in allowable error that a hardness tester can read otherwise needs to be serviced.

So, the decimal place values are significant values that are required for calibration to give any HRC reading any value when sharing with others.

 

[ak650]

It's a part of the standard test method for rockwell hardness testing.

ASTM E18-22

Before the year 2000 the United States was lagging behind in the accuracy and quality of hardness testing compared to Japan and Europe due to a lack of standardization and universal best practices.

In 1991 the American Society of Testing and Materials (ASTM) requested the help and direction of the National Institute of Science and Technology (NIST) to develop a national standard for Rockwell Hardness testing.

It took seven years and wasn't rolled out fully until the year 2000 with E18-00.

Standard reference materials (SRM) with traceability to the NIST master blocks and indenters. That way everybody can be on the same page.

The harder blocks have a 0.5rc tolerance in allowable error that a hardness tester can read otherwise needs to be serviced.

So, the decimal place values are significant values that are required for calibration to give any HRC reading any value when sharing with others.

And using a +-0.5 standard to calibrate a +-1.0 instrument is generally only acceptable when there is no alternative. The rule of thumb during my time in Metrology, was that the standards used to calibrate an instrument, had to be at minimum, four times as accurate as the unit under test. For example, if you were calibrating a voltmeter to +-1.0V, then the voltage standard used, had to have an output that is +- 0.25V or better.

 

[fitzo]

DeadboxHero Thank you for the explanation. I am looking for the specification but ASTM Int'l wants $90 and that's a bit much for casual interest. Found the first page at least, so I get the why and how. I know from 50 years ago it was common practice to interpolate decimals between the numbers. That said, I can see by your explanation that there is significance to that interpolation that matters to the testing standard. However, what I was wondering about, from the mathematics perspective, is whether that fraction would be considered a "significant number" or not. It's been a long, long time since I dealt with calculating system error and significant figures, so I am mostly just jaw-jack here. Thanks, again, for the info. I'll keep looking for that spec.

All that said, the new digital machine measure to tenths, at least, don't they? Slightly different story, then.