Venting about carbide order- learning the hard way that 3/32” comes 20% oversize. So much grinding…

[KevinCunningham]

Howdy

I was referred to Centennial carbide and specifically their ultra-grain blanks by another engraver. He let me try his setup which worked great- he buys their 1/16” round stock and uses the GRS collet system so once a graver is locked into a collet it can be indexed repeatably for sharpening.

Well I am using a Lindsay classic- I like the 901 but I’m not ready to invest right now. My handpiece takes 3/32” square blanks and I sharpen all my different point shapes on a GRS grinder with the oldschool dual angle tool post that can repeatably clamp square shank gravers really well.

So I figured maybe I’d get 1/16” rounds in their ultra grain and figure it out, possibly even braze them into 3/32” 1/64”wall brass square tube for repeatable sharpening. But the didn’t have ultra grain in that size- it would be a special order. So if I was making a special order why not just get 3/32” square stock in the first place right?

I’ve done a lot of metal work and fabrication and in my experience metal is sold by actual size, sometimes for extra $ with a smaller +- tolerance, not like wood where a 2”x4” is actually much smaller. But when my custom order finally comes all the blanks are .113” +- about .0015, which is bigger than 7/64” and approaching 1/8”! 20% too big to fit in my handpiece.

I contacted Centennial and they said oversize is industry standard. Since I’m not a professional carbide tool manufacturer I have to take their word for it. I asked if I ordered 1/16” square next time what actual size could I expect but haven’t heard back yet.

I made a sharpie mark for how much shank I’d need on a roughing diamond wheel and figured out that grinding 1 minute 45 seconds on one face, then 1 minute 35 seconds on the next in my dual angle fixture gets me a shank that will load into my handpiece. My old Lindsay slotted collet that bolts onto his templates is a handy go/nogo gauge. what a dusty boring pain in the butt. I can do 10 in about an hour but then I still have to clearance and profile them before I can even polish & sharpen them…

Anybody else have this experience? It still beats buying Steve’s (really nice) blanks at $20 a pop but I’m really learning the hard way on this one.


In this pic is a Centennial 3/32 blank along with one of Steve’s actual 3/32” blanks- you can see the size difference.

 

[T.G.III]

Suppose it just depends on what your time is worth

 

[S&w right]

I ordered 100 from centennial about 2 years ago. No issues at all. They are 10% cobalt

 

[KevinCunningham]

I ordered 100 from centennial about 2 years ago. No issues at all. They are 10% cobalt

Yeah I sharpened and cut with a dozen of them today. It took an extra hour to get them ground but they cut fine.

What did you order and what did you get? How do you use it?

 

[monk]

quite sometime ago i ordered blanks from centennial. mine were spot on. maybe i was just lucky??

 

[KevinCunningham]

quite sometime ago i ordered blanks from centennial. mine were spot on. maybe i was just lucky??

I don’t know. They made me feel like I called home depot and asked why my 2x4s were neither 2” nor 4”- it’s the industry standard duh.

I’ve been online looking and I found references to people looking for non chinese “finish ground” carbide blanks as opposed to how it’s normally sold “carbide strips” which are made oversize so they can be ground to the user’s tolerances. The wierd thing is that they were so much bigger- 20 thousandths extra is kind of a lot when you only asked for 93 in the first place.

It’s especially baffling that they don’t have a list of actual sizes so folks can get what they actually need- because tungsten carbide is so hard to grind and cobalt is so expensive…

And now I need to drag the shopvac out for dust control

 

[Sam]

You might consider that the precious time spent running in circles trying to save $10 could have been spent practicing drawing or engraving. Even if a graver cost $100 ea you can do $25,000 worth of work with it.

I will also say that I've been guilty of doing similar things, so I have no room to lecture anyone.

 

[KevinCunningham]

You might consider that the precious time spent running in circles trying to save $10 could have been spent practicing drawing or engraving. Even if a graver cost $100 ea you can do $25,000 worth of work with it.

I will also say that I've been guilty of doing similar things, so I have no room to lecture anyone.

Ha! Yep.

Reminds me of what my grandmother called “the lazy man’s load” when you struggle instead of just taking two trips.

In my baby engraving career I’ve found some success and continued good paying work cutting some pretty hard & tough guns. I assume those with more skill and experience are able to make the hourly wage they need without having to sharpen so much carbide. As long as I can do my best work and just have to suffer much more carbide dust I’m ok with it. But it means I need a lot of blanks so I can batch sharpen and be efficient.

So I did 13 that first day and I’m doing one more every time I sharpen. It takes me about 5 minutes extra per graver blank, so not bad.