rsser
23rd November 2009, 09:49 AM
The promise of the Tormek Bench Grinder Mount is transferability of setup from dry grinder to wet grinder to honing wheel.
So if you have a new or 2nd hand tool that needs reshaping, or you are looking to establish consistent bevel geometries across your kit you might like me think that the BGM would be a good investment.
And if you're a turner you might expect that geometries can be determined and repeated by following the painting by numbers approach with the Turning Tool Setter (but this little plot line comes in a later chapter of my Frolics book).
The Tormek claim is that once a bevel is shaped on the dry grinder, a quick lick at the same settings on the wet wheel will give you a good edge and waste v. little precious metal.
In this first episode of Frolics I will relate a story about the promise of transferability. The subject is a humble firmer chisel that came to casa del Ern with a sorry steep bevel and knicked edge. The task was to rehabilitate it with a 25 degree bevel and 30 degree 2ndary bevel.
Onto the dry grinder then, using the BGM and the Tormek square edge jig. The jig promises reliable 90 degree ends to the tool.
Taking things very easy to avoid detempering, I had first jointed the edge and then went on to shape the bevel using the jig. Two or three passes at a time on the 60 grit white wheel to start with and then one light one as soon as we were down to an edge. Great care is needed at this point to avoid bluing. Keeping the wheel clean with a dressing device is essential.
Now why would you bother with the bluing risk when another promise of the Tormek is that it eliminates it altogether? Well, I started with the Tormek, which was brand new, but found it very slow indeed and the wheel clogged quickly. Very different from my Scheppach.
Anyway, once the bevel was shaped I went to transfer it in the jig to the Tormek for the sharpening stage. But no, it won't transfer. The chisel is well to the right of the wheel. Hmm. Curious. I got out the older straight edge jig to see if the different design would allow the transfer. No, not it either. So the chisel has to be removed from the square edge jig and the jig turned upside down since only one side of the slot is good for registration. (The same is true of the straight edge jig).
So it has to be set up anew.
Once the wet wheel had done its work I then flipped the mount bar to the honing side, expecting to transfer the jig to that side for a quick polish of the bevel. But no, the chisel had to be turned around in the jig again.
That done Mr Firmer was mounted in the Veritas honing guide to have his 2ndary bevel done. Hmm, after a few strokes a skewed bevel started to appear. I kept it up and finished that bevel and checked the end against an engineer's square. All kosher. So the Tormek set up is the problem, or my use of it.
I redid the firmer on the wet wheel carefully ensuring a good seat against the jig side. Out of square again. I checked the chisel sides; they were parallel.
So maybe the wheel was out of true so I gave it the treatment with the truing tool. Now incidentally this improved the cutting speed greatly, so for other new Tormek owners, I don't think this is in the manual and it's well worth doing before you have my kind of reaction when using the unit out of the box.
I posted these problems on the Tormek forum on which you get quick and useful responses, even on a Sunday, from Jeff Farris, the US sales manager.
On the promise of transferability from dry to wet grinder, Jeff advised that the BGM is primarily intended for turning tools (my emphasis).
Well that's useful to know, even after the fact, so you might avoid again crawling over the manual, the mounting setup, the jig orientation, and whether you should hold your pinkie up when sliding the jig, in order to find the problem. The problem is with your expectations.
It may be possible to deal with the problem by moving the BGM 50mm further to the right of the dry grinder than is recommended in the manual. That will have implications for how other jigs fit that need to be tested.
Now that the Tormek wheel was cutting at a decent rate, it was feasible to do all the shaping on it rather than the dry grinder; Jeff estimated in the order of 3-4 minutes time.
On the out of square issue, Jeff suggested checking that the firmer back was flat (it was) and attending to how the jig mount bar was inserted, both during truing and during jig use. You need to push down at the threaded rod point to ensure it sits square. Now I haven't tried this yet. That will be today's frolic. I don't recall reading about it in the manual; it's the kind of thing I'd remember so yet another crawl through it is called for so I can test my recollection.
Another wrinkle that emerged in this chisel rehab exercise has to do with the square edge jig specifically. This comes with a screw-in stop that goes into the mount rod end so you don't inadvertently slide off it ruining all your good work. The problem is that the end of the rod is tapered (presumably to ease the sliding on of jigs) so your jig drops at that end before you get to the stop, so throwing it out of alignment. Now this didn't appear to be material on the wet grinder because you're pressing down on the tool tip and this is pretty much over the inboard bush and in practice alignment is maintained.
But it is a problem with the BGM as you have to use light pressure to avoid bluing and the jig side can drop a little if you slide it right to the end. So it's not a useful feature and the promise of being fool-proof that goes with it is misleading. It can in fact give you worse results than if it weren't there.
So that's chapter 1 of the story folks.
Elsewhere you can find snippets about the gouge jig manufacturing error (and if you read the Tormek forum, the planer blade jig manufacturing error), the snafu with one retailer thinking the BGM came with two mounts (quickly and ethically dealt with), and the later bonus offer from Tormek of the BGM with two mounts to subsequent buyers.
So if you have a new or 2nd hand tool that needs reshaping, or you are looking to establish consistent bevel geometries across your kit you might like me think that the BGM would be a good investment.
And if you're a turner you might expect that geometries can be determined and repeated by following the painting by numbers approach with the Turning Tool Setter (but this little plot line comes in a later chapter of my Frolics book).
The Tormek claim is that once a bevel is shaped on the dry grinder, a quick lick at the same settings on the wet wheel will give you a good edge and waste v. little precious metal.
In this first episode of Frolics I will relate a story about the promise of transferability. The subject is a humble firmer chisel that came to casa del Ern with a sorry steep bevel and knicked edge. The task was to rehabilitate it with a 25 degree bevel and 30 degree 2ndary bevel.
Onto the dry grinder then, using the BGM and the Tormek square edge jig. The jig promises reliable 90 degree ends to the tool.
Taking things very easy to avoid detempering, I had first jointed the edge and then went on to shape the bevel using the jig. Two or three passes at a time on the 60 grit white wheel to start with and then one light one as soon as we were down to an edge. Great care is needed at this point to avoid bluing. Keeping the wheel clean with a dressing device is essential.
Now why would you bother with the bluing risk when another promise of the Tormek is that it eliminates it altogether? Well, I started with the Tormek, which was brand new, but found it very slow indeed and the wheel clogged quickly. Very different from my Scheppach.
Anyway, once the bevel was shaped I went to transfer it in the jig to the Tormek for the sharpening stage. But no, it won't transfer. The chisel is well to the right of the wheel. Hmm. Curious. I got out the older straight edge jig to see if the different design would allow the transfer. No, not it either. So the chisel has to be removed from the square edge jig and the jig turned upside down since only one side of the slot is good for registration. (The same is true of the straight edge jig).
So it has to be set up anew.
Once the wet wheel had done its work I then flipped the mount bar to the honing side, expecting to transfer the jig to that side for a quick polish of the bevel. But no, the chisel had to be turned around in the jig again.
That done Mr Firmer was mounted in the Veritas honing guide to have his 2ndary bevel done. Hmm, after a few strokes a skewed bevel started to appear. I kept it up and finished that bevel and checked the end against an engineer's square. All kosher. So the Tormek set up is the problem, or my use of it.
I redid the firmer on the wet wheel carefully ensuring a good seat against the jig side. Out of square again. I checked the chisel sides; they were parallel.
So maybe the wheel was out of true so I gave it the treatment with the truing tool. Now incidentally this improved the cutting speed greatly, so for other new Tormek owners, I don't think this is in the manual and it's well worth doing before you have my kind of reaction when using the unit out of the box.
I posted these problems on the Tormek forum on which you get quick and useful responses, even on a Sunday, from Jeff Farris, the US sales manager.
On the promise of transferability from dry to wet grinder, Jeff advised that the BGM is primarily intended for turning tools (my emphasis).
Well that's useful to know, even after the fact, so you might avoid again crawling over the manual, the mounting setup, the jig orientation, and whether you should hold your pinkie up when sliding the jig, in order to find the problem. The problem is with your expectations.
It may be possible to deal with the problem by moving the BGM 50mm further to the right of the dry grinder than is recommended in the manual. That will have implications for how other jigs fit that need to be tested.
Now that the Tormek wheel was cutting at a decent rate, it was feasible to do all the shaping on it rather than the dry grinder; Jeff estimated in the order of 3-4 minutes time.
On the out of square issue, Jeff suggested checking that the firmer back was flat (it was) and attending to how the jig mount bar was inserted, both during truing and during jig use. You need to push down at the threaded rod point to ensure it sits square. Now I haven't tried this yet. That will be today's frolic. I don't recall reading about it in the manual; it's the kind of thing I'd remember so yet another crawl through it is called for so I can test my recollection.
Another wrinkle that emerged in this chisel rehab exercise has to do with the square edge jig specifically. This comes with a screw-in stop that goes into the mount rod end so you don't inadvertently slide off it ruining all your good work. The problem is that the end of the rod is tapered (presumably to ease the sliding on of jigs) so your jig drops at that end before you get to the stop, so throwing it out of alignment. Now this didn't appear to be material on the wet grinder because you're pressing down on the tool tip and this is pretty much over the inboard bush and in practice alignment is maintained.
But it is a problem with the BGM as you have to use light pressure to avoid bluing and the jig side can drop a little if you slide it right to the end. So it's not a useful feature and the promise of being fool-proof that goes with it is misleading. It can in fact give you worse results than if it weren't there.
So that's chapter 1 of the story folks.
Elsewhere you can find snippets about the gouge jig manufacturing error (and if you read the Tormek forum, the planer blade jig manufacturing error), the snafu with one retailer thinking the BGM came with two mounts (quickly and ethically dealt with), and the later bonus offer from Tormek of the BGM with two mounts to subsequent buyers.