Thread: Robert Sorby Pro-Edge Sharpening System

Bang for buck is a bit hard to calculate.

Yes, the initial cost of machine and jigs can be totted up.

Then there's the versatility and speed of the systems.

The appeal of the Pro-Edge is that I can go way coarser than a wetgrinder (c. #220 min.) and I have lots of old bench chisels to rehab. Reshaping a bevel at #60 is much quicker than at #220. And I can lap the backs; a wetgrinder wheel might give you 3 lappings on each side of the wheel and then you face the problem of deglazing and perhaps truing it.

The big unknown is long the belts last. Sorby Ceramics are c. $10; Trizacts c. $20 Well the ceramic belt has done four chisel lappings and there's life in it yet. So the worst number is $2.50 each. You know how long it would've taken to do those on a coarse ceramic whetstone or an extra coarse diamond plate?! And diamond plates are exxy and I've worn several out. A ceramic stone is more cost effective but takes a bit of maintenance.

A Tormek wetgrinder wheel should last a hobby woodworker a good length of time but when that time runs out the bill is c. $350.

Well, I don't hone anything, except the few times I actually use a skew. I do have a Tormek, and use it for my kitchen knives. I do everything else on the CBN grinding wheels, and I expect them to outlast me, which given my dad's age of 90, leaves me almost 30 more years. No problems with the harder carbon steel like my bench chisels, when I need to fix the edges. I have heard that there are CBN abrasive belts, and diamond ones as well. Don't know where to find them though.

robo hippy

Yep; Sorby do a diamond belt. Haven't asked about the cost!

Good for TCT cutters, router bits etc, and glass, stone & ceramics.

If memory serves Lee Valley may also do a 1" diamond belt.

Originally Posted by robo hippy

I have heard that there are CBN abrasive belts, and diamond ones as well. Don't know where to find them though.

Originally Posted by rsser

Yep; Sorby do a diamond belt. Haven't asked about the cost!

Finding CBN and diamond belts might be easier than paying for them, going by this price list (and those are £s not $s).

You would have to be convinced that the diamond was going to last 12 times longer than the Trizact.

My concern isn't that the diamond wouldn't outlast the Trizact by a factor of ten, but that neither the belt itself nor the bonding of the diamond to the belt would last as long as those expensive diamonds. You would have to be convinced that the belt and bonding were going to hold together to get your full value out of the diamonds.

Seeing a shredded diamond belt on the floor could make a grown man cry...

thanks for the feedback Ern have forwarded the info to Robert Sorby for their answers about the joint on the belt.
The diamond belt comes in around the $280 mark yep not something you just buy.
Also not that good on HSS tools, as you noted the 3000 trizac leaves a very smick edge and not that much work.

Originally Posted by NeilS

Seeing a shredded diamond belt on the floor could make a grown man cry...

Just looking at the price gave me heart palpitations.

Wow.

But to be fair the belt is 50mm by c. 760mm.

That's a lot of 'girl's best friend'

Neil, it's an itch I'm not going to scratch at this time but a shredded belt might make for a funky necklace in some quarters.

Anyway, next test will be to clean up the back of an M2 plane blade of mic-d's with surface grinding that was rough. Will try a grit or two on the ProEdge and then transfer it for finer grades to WorkSharp discs mounted on a arbour on the lathe.

Meantime I'm hanging out for the finer Trizact belts to come from the UK.

Just as an aside re efficiency, on a pink #80 wheel I had to do a minor reshaping job on a 3/8 spindle gouge, and then touched up a couple of scrapers. The wheel then needed cleaning. Cough, splutter.

Yeah, a CBN wheel looks the goods but I'm trying to keep the sharpening kit cheap and simple as I'm taking cash-strapped students through the sharpening process. Almost all can be done with a bench grinder, AlOx wheels and a $40 platform with a bit of practice. For fingernail grinds, add a Tru-grind jig.

For those who want more versatility, the Pro-Edge looks to me, so far, to be a better option than a wetgrinder. And I've had two of those.

Episode X:

Took a 3/8" close to straight-across grind bowl gouge to the #120 AlOx belt.

This is my std hacking gouge and I normally freehand it on the platform in front of a coarse blue wheel. Swing it a bit side to side to pull back the wings.

In this case the V block was used. Yielded a 'lady-finger' grind.

Same deal as with the beading/parting tool: dubbing over of the tip, and the clunking of the join was audible and felt. Pulled back til clunking disappeared. Metal removal was slower. Dubbing over was almost ground out. Belt inspection showed a build up of grindings on the join but not elsewhere.

Then to the fresh #240 AlOx. Distinct clunking. Pulled back til it went. Again, ground metal appeared on the belt joint but not elsewhere.

Got a good edge in my book. #120 produced a burr felt by finger. Not the #240. #120 also produced a more polished surface (to the eye); #240 tended to a haze.

Then to the fresh #600 (equiv.) Trizact. For a fine abrasive it was ripping the metal off. Dubbing over happened again. A join matter on a fresh belt I'm sure now. Pulled back; light touch; took it out. Near-polished surface.

As a mostly freehand sharpener I'm happy with these trade-offs. In a turning session I want to quickly refresh the edge from time to time and the V block and step-fixed solid platform setting can do this. I like the V block as it's half way between freehand and a clamped jig. With a clamped tool you have to check and adjust the protrusion where you expect metal removal may have changed the angle.

After all that I pulled the belt off to check the scored platen and the rollers. A few sticky deposits were present and easily removed with 0000 steel wool. Expect Mr Sorby's liberal protective oil coating on the steel plates on the machine was the cause. Wiped it off; will redo it with G15.

In this session the grind angle was set to 45 degrees. It was still possible to change belts without removing the platform. Refitting the side cover has proved easier when started with the top screw.

The more time I spend with this system the more I like it.

It's all a matter of what trade-offs you can live with of course.

Episode XI:

Tried something more challenging. Thompson detail gouge, 7mm flute width. Also 10% Vanadium so a curl ball for the abrasives. 30 degree bevel so quite a long overhang from the platform.

I like this with a bit of fingernail grind and doing that just on the platform is beyond my skills so it's been a jig job. And even then it's easy to cock it up as there's an exponential reduction in metal as you rotate the shaft up the 'wings'.

Tried it on the V block so a bit of reshaping was needed. Started at AlOx 120 but this was so slow that I was getting facets standing around whistling . Dropped to Zirc. 60 to rough out the grind, with better results. Then 120 and 240.

Overall this was tricky and somewhat time-consuming work. Of course the grind changed with square across presentation, but I finished with one pass at 120 and later at 240 by rotating the shaft and pushing the bevel up on the abrasive to pull the wings back a bit.

The extent of overhang also reveals a downside of this semi-freehand approach. There's a bit of slop (necessarily) in the V block rail and it's easy to get some movement of the gouge shaft in the block. So care is needed.

The abrasives as they are coped fine with the V10 steel.

I'm finding this thread interesting, and have enjoyed reading it. Please don't stop posting just because no-one is replying

Originally Posted by Colin62

I'm finding this thread interesting, and have enjoyed reading it. Please don't stop posting just because no-one is replying

Yes, keep posting. Thanks for doing the research.

The comment about the expensive abrasives sticking to the belts they are on would be a big concern. Heat build up is minimal, but the constant bending of going over the top and bottom rollers would take it's toll. That is the advantage of the electroplated CBN wheels. No flex. While expensive, they are a far better buy than any other grinding wheel available. Like some one once said, "Buy the expensive tool, you cry once. Buy the cheap tool, you cry every time you use it."

robo hippy

RH, if you read the post you would've seen I was referring to a few sticky deposits on the platen and rollers, not on the belts.

And I'm not interested in debating the merits of this v. a new-era wheel. I'm sure the CBN is good. I run a diamond wheel myself and have had very satisfactory results with it. But neither of those are sharpening systems.

Paul and Colin: thanks. It's become a kind of WIP.

I should've added re the detail gouge that one of the things that makes the work tricky is that the bevel at the tip is very long. If an edge refresh is as tricky as yesterday's work then I'll use the gouge jig.

That's so much for all your work Ern
As the pro edge is some what new to the market it's good to have someone doing a test drive of it
and telling us what they think

Being some what tight with my cash it's good to know what I'm thinking of getting is money well spent