Hardness Tester

Aug 26, 2007 17 Replies

I have a need for a hardness tester, and was thinking of making the Dave Lammas design as published in ME in 1989 (August/September IIRC).



Has anyone here made this design? any suggestions, improvements, traps to avoid?



David


In article , David Littlewood writes

Seems no-one has any useful experience to put forward.

I went to Blackgates Engineering yesterday, and found that one of the casting patterns has got broken, and that since they only sell about one set a year they are not giving any priority to repair or replacement. I bought the last (incomplete) set of castings. Blackgates are AFAIK the only suppliers.

If anyone has a set of castings they don't need, or knows of another source of castings, please get in touch (david at dlittlewood dot co dot uk).

David

In message , David Littlewood writes

[snip]

As the result of two such examples of customer care, Blackgates is a firm I now avoid (see note below). Have you looked at the possibility of fabricating the part?

Note: Does anyone know an alternative source of "Curly spoke" slate wagon wheel castings (5" gauge, 3 3/4" diameter)?

If you think Blackgates are bad, just wait until you have reasonable and legitimate cause to complain to Reeves 2000 about casting quality and a certain female gets on your case!!!

--

Chris Edwards (in deepest Dorset) "....there *must* be an easier way!"

In article , Mike Hopkins writes

To be fair, they have to be commercially minded about these things - if they sell one a year, it cannot take priority over other things, and I can't claim they failed in any duty to me.

Yes, I have looked at the missing casting, and it could be fabricated - that is why I bought the rest. Would be a bit of a chore though.

David

No, sorry. But you made me curious. A DIY hardness-tester? Which method? Did they find a cheap replacement for the diamond? :-)

Nick

David,

I have a "Warman Penatrascope" that you can borrow if you want. It's a dimaond pyramid device and will take samples up to about 3" thick. As it's on my study shelf as an ornament, it's one of the few engineering things not crated and palleted. (I had to go and buy a battery charger this morning, as the four I have are inaccessably crated!!)

AWEM

Yup,

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Third one down, cheap enough for you ??

I've got an ancient Firth hardness tester, missing a few bits such as the testing ball and in need of a good clean, which you could have for nowt if you can collect it or maybe even speak to Charles, depending upon where you are. (I've got a much tidier version which I'm keeping).

Tim

Hi Nick,

It uses the Vickers method, with a 30 or 120 kg effective pressure and a

138 degree tungsten carbide 4-square pyramidal cone. This is good enough for any steel, obviously not for carbides or other exotic stuff (for which you need a diamond). You have to grind the pyramid yourself, but as I have a Clarkson that should be easy enough.

Let me know if you would like more details.

David

In article , Andrew Mawson writes

Andrew,

That's most kind, I'll take you up on that, at least it will keep me going until I get around to making the Lammas one.

You should have said about the charger, I have one here you could have borrowed.

Any update on the move date?

Regards,

David

In article , John Stevenson writes

Thanks John. I have a couple of those exact ones, but I don't think the diamond shape is precise enough; also not sure if the setting is up to the pressure. I may give it a go when I've made the instrument, but for what I need to do a tungsten carbide pyramid will be hard enough.

David

In article , Tim Leech writes

Gosh, that's generous Tim - where are you? You speak of ball, do I take it that it is Brinell or Rockwell?

david at dlittlewood dot co dot uk

David

Don't get too excited, you haven't seen it yet Probably better approached as a good basis for a tester, than a tester which just needs TLC.

I'm near Warrington. It's for Brinell though with smaller ball and therefore smaller forces then the standard Brinell tester. The later version I have (variable force) can also be used with a diamond, not sure whether that applies to this one (fixed force).

Tim

In article , Tim Leech writes

Tim,

I travel up to Lancashire most months (unfortunately just got back yesterday) so I could come and inspect. Would it fit in the boot of a (large) saloon car?

Could you please send me your un-munged e-mail address to david at dlittlewood dot co dot uk?

David

engineering

charger

David, I'm arround tomorrow (Sunday) if you want to come and collect - give me a call. Move date not definate yet - contracts are signed but not yet exchanged - it's looking like 3rd week in October, but that is bang on when my Daughter is getting married !!!!

AWEM

Easily. Imagine an ordinary bench microscope, it's a little bit bigger but many times heavier.

Should be readily decipherable from here.

Tim

My regular onetel email is playing up yet again, I tried to email you from my Yahoo address & it's bounced back, host not found.

Tim

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