Ian,

I do a lot of work on reclaimed welded shafts which is hard on tooling. I use reground tips all the while to get under the weld.

I'm more or less standardised on the triangular TPUN series and just lick the corners and top on a diamond wheel on a small cutter grinder but do it free hand. Much of the time the tip is still good enough after getting under the weld to finish to a bearing size which has to be nob on.

Never got to the trouble of brazing them as I think that defeats the object and turns a 3 point insert into a one point and so easily scrapped.

Sometimes I can get 9 lives or so from one insert.

John S.

Hi Ian,

I make tooling brazing carbide tips to pieces of steel. The thing you must do is grind off the TiN coating first ( the flux and braze will not wet this).

Good luck.

Peter.

Hi John

I was discussing this with an engineer mate a few days ago. He told a story of an apprentice wrecking 2 large diamond wheels grinding mild steel at the factory he ran. Not low cost import wheels. 9" industrial cup wheels (In a tool grinder with an angle table) serious money to replace. So I know it can happen. I would not be surprised to find that a lot of the cheaper wheals are not in fact natural Diamond. Maybe they are CBN or some other man made concoction; CBN is OK on Steel.

I have a couple of bench grinders set up with silicon carbide wheels of various grades plus the Epoxy Warden I made fitted with a Diamond wheel most of the time.

I guess it is a matter of trial and error. for fine work and a light touch maybe its OK? In any event for hogging into a chunk of steel and moving metal I still prefer to use conventional wheels. I will keep the Diamond for fine HSS and Carbide work. I do transgress and use it to finish my scrapers, but it is only removing a few thou.

Cheers

John

Edited By John McNamara on 19/06/2012 13:42:51

John Mc,

Probably you are correct in that they are not 100% diamond, in the past when decent wheels were over £100 a pop and wages at £40 a week I wouldn't have dared try it but given current pricing it's a no brainer and I have found out it works.

Proves how things move on, recently I have had a big clear out, sold a big slotting machine and scrapped a 10" x 84" TOS lathe which has left the place looking like a WWII bomb site.

Culling this very severly, over 3 tonnes of gear has gone for scrap but I have found stuff I have forgotten about or in cases didn't even know I had.

Amongst this lot were two bench grinders that used a dished green grit wheel for sharpening brazed carbide tooling from ages ago. These were freely give away to two local model engineers who though they were brilliant.

I didn't have the heart to tell them they were abandoned because in light of present technology the green grit wheel is alongside the millstone. Green grit wear away like crazy, it has to when presented with a harder material. Add to this if you examine the edge after grinding thru a glass it looks like the edge of a paving slab and still need honing or finishing on a diamond wheel which is where we came in.

Instead of a green grit for roughing get one of those diamond blades that ARC sells to fit an angle grinder. These will back tunsten off from a brazed tip tool fast than anything out there, you get two sides and mine after 3 years is still on the first side and I often have to take a whole 1/32" off the face of a 20mm square cutter.

Depending on grade you can sometimes get an edge that doesn't need finishing, even if it does it takes less work than a green grit wheel.

All my green grit wheels have now been given away or thrown at next doors cat.

John S.

Edited By John Stevenson on 19/06/2012 20:11:00

I had a Drill Doctor for a while; they are fitted as standard with a diamond wheel, and are most certainly intended for use on steel.

Regards,

Tony