Thread: Diamond Tool Holder

Originally Posted by kwijibo99

Sorry for going a bit off topic but I was just wondering if Bryan had a copy of the Milling speeds nomogram he could post?

Greg, I'm guessing the missing word is 'bigger'? The one I posted should come up quite large. In my browser I can keep clicking on it and it will blow up. Anyway try a right click and save as, then see how it looks in your preferred image viewer. If you have no joy I can email you a copy.

Oh wait, I just re-read your post and the missing word - from my comprehension - was 'milling'. The answer is yes I have it in the book but not scanned as yet. Things are a little crazy around here but I will see if I can scan it for you. Soon.

Originally Posted by Bryan

Greg, I'm guessing the missing word is 'bigger'? The one I posted should come up quite large. In my browser I can keep clicking on it and it will blow up. Anyway try a right click and save as, then see how it looks in your preferred image viewer. If you have no joy I can email you a copy.

Oh wait, I just re-read your post and the missing word - from my comprehension - was 'milling'. The answer is yes I have it in the book but not scanned as yet. Things are a little crazy around here but I will see if I can scan it for you. Soon.

Thanks Bryan that would be great, no hurry though whenever you get around to it will be fine.
Cheers mate.

Hi,

I've done so more cutting with the DTH using both standard HSS and Crobalt HSS.

I used the Crobalt on the bright bar following Gary's suggestions, the biggest DOC was 1.5mm, anything more than that was too scary on my little Hercus. I'm happy enough with that, even with a carbide insert tool I don't really go much bigger.

I'm still not getting a big DOC with the HSS, from memory the biggest was about .5mm but the finish is really good.

I turned up a brass mortar barrel tonight using the HSS and DTH, and it came up really nice. So overall I'm happy with my purchase so far.

Ben.

I'm now thinking maybe I should get a bigger lathe, like that Harrison on ebay and gumtree...

Ben,
Glad you like the DTH. Just to clarify, Crobalt is not HSS. There is Cobalt HSS. Crobalt (with a r) is an alloy that does not contain any iron.

http://www.crobaltusa.com/whatiscrobalt.htm

Cheers,
Chris

Hi Chris,

Thanks for that, I had a look but couldn't find anything about Crobolt. I didn't try CroboltUSA though. Good site. It does work much better than HSS. I knew there was a difference between HSS Cobalt and Crobolt but I did think Crobolt was still HSS.

Cheers Ben.

Hi,

Thought I'd quickly post these pictures of some black bar I turned up today.

I think the biggest cut was 1.2mm off the Diam at roughly 720 rpm. The DTH with Crobolt finish is nearest the headstock and carbide cut is on the right. Probably hard to tell but the DTH has much smoother finish, still comes out greyish with wavy lines but a lot better than the carbide (which i used to remove the hard scale). Also, the tip hasn't been sharpened for awhile.

Ben

Hi Ben,
What Dia is the bar? I'm guessing 20-25mm? It looks to me like your surface speed with the carbide tool was too low, i generally push carbide at 400fpm (higher for finishing cuts) for a 1" bar thats 1600rpm. Probably higher then the hercus will go but carbide loves speed.....

The DTH cuut looks good, i keep telling myself i will buy one but other things always seem to crop up.

Ew