Sharpening

[D_W]

full speed here is typically 3450-3600 rpm, but anything high 2000s or more is probably "full speed"., maybe for no reason other than the electric cycles?

Electricity is 60hz here.

If it's 50hz where you are, then maybe that's about proportional compared to that range.

Half speed grinders here are generally around 1725 rpm or a little more.

The speeds you mention would be fine. I wouldn't want a slow speed 6" grinder, it's just encouraging you to increase pressure to make up for wheel speed and there's some balance where that becomes a problem. On everything that has any kind of speed.

 

[yan89]

I have the T3 which I think has become the T4 in the current range.

Either of these will do what you are looking for

https://www.tormek.com/uk/en/grinding-jigs/se-77-square-edge-jig/
https://www.tormek.com/uk/en/grinding-jigs/svd-110-tool-rest/
It works for me but I’m definitely not holding it out as the right way for everyone. I settled on it after doing a course with Chris Tribe in Ilkley where various methods were available to try.

I re-established the bevel on a Clifton Plane iron on Saturday in about ten minutes. I have no doubt others can match or beat that with their chosen method.

I did that same course around 6 weeks ago, in the same shop, but with Nick Thompson who I think bought the shop from Chris, or did a joint venture, a few years ago. He still champions Chris’ work, so much so that I immediately bought his book when I’d left!

 

[Jameshow]

Sorry to continue questioning, but when you say 'full speed' 6 inch grinder, is there a set speed it should (or shouldn't) exceed? I'd rather not drop £4-500 on a Tormek before I know i'll get benefit out of it, but there's grinders available new on a certain brazilian rainforest themed site for £40 (Einhell TH-BG 150 2980RPM), £55 (Clarke CBG6RP 2900RPM) or £83 (Record RPBG6 2850 RPM) which wouldn't seem like as much of an investment in the short term

Would not this titan be better vfm with 400w/ 8in diameter.

https://www.screwfix.com/p/titan-tt...ri6bhEVnUJPB80IB_LkaAvXbEALw_wcB&gclsrc=aw.ds

 

[CMax]

This might be an ignorant question, but I've never owned a grinder or polisher: can a grinder take a polishing wheel, so that all I'd need is one machine with a coarse grinding wheel on one side, and the appropriate stitched mop on the other?

 

[yan89]

Would not this titan be better vfm with 400w/ 8in diameter.

https://www.screwfix.com/p/titan-tt...ri6bhEVnUJPB80IB_LkaAvXbEALw_wcB&gclsrc=aw.ds

Certainly looks it James - cracking suggestion! Thanks

 

[raffo]

This might be an ignorant question, but I've never owned a grinder or polisher: can a grinder take a polishing wheel, so that all I'd need is one machine with a coarse grinding wheel on one side, and the appropriate stitched mop on the other?

Yes, that's what I do. Match the diameter of the wheel and the diameter of the arbor when getting the buffing wheel.

 

[Derek Cohen (Perth Oz)]

This might be an ignorant question, but I've never owned a grinder or polisher: can a grinder take a polishing wheel, so that all I'd need is one machine with a coarse grinding wheel on one side, and the appropriate stitched mop on the other?

Yes. I have two half-speed bench grinders. One is set up with CBN wheels, as mentioned earlier, and the other with two polishing mops, a soft and a hard. The latter are used for sharpening, ala David’s Unicorn method …

Regards from Perth

Derek

 

[CMax]

Thanks chaps!

 

[yan89]

Out of interest, anyone got any recommendations for good tool rests and wheel dressing tools?

 

[D_W]

Out of interest, anyone got any recommendations for good tool rests and wheel dressing tools?

Make a rest design out of plywood to start and see if you like how it operates, affix it to something other than the grinder and screw down the grinder. if you like the design you make, you can either face it with spring steel, or you can remake it. I wouldn't buy anything, especially not an aluminum rest or anything that isn't cast iron or steel.

For dressing wheels, the T shaped very cheap dresser is what you want.

https://www.ebay.com/itm/4037052607...LoNWc6Gj1F85GMguJq1eW1JDSXWf|tkp:BFBM0Jvo9NJg
I've been using one of these for a long time and the diamonds have never really worn off of it. Probably 14 years old at this point and has worn several wheels to the point of replacement. they're just imported by the tens of thousands, so find a seller with the same thing and shop on price.

 

[D_W]

Note on that dresser, it's just a square tube with a layer of coarse diamonds. There's another type with what looks like a rectangle of who knows what stuck on the end - no clue if the latter is OK - I'd stick with something that looks exactly like above - it should outlast you and the T shape makes it easier to take light bits off of a wheel and keep the contour where you'd like it.

There is a single point expensive type that a machinist or tool and die shop would point you to, but they are more suitable for heavy removal on a large wheel. Something you should never have to do.

 

[yan89]

Note on that dresser, it's just a square tube with a layer of coarse diamonds. There's another type with what looks like a rectangle of who knows what stuck on the end - no clue if the latter is OK - I'd stick with something that looks exactly like above - it should outlast you and the T shape makes it easier to take light bits off of a wheel and keep the contour where you'd like it.

There is a single point expensive type that a machinist or tool and die shop would point you to, but they are more suitable for heavy removal on a large wheel. Something you should never have to do.

Thanks for the extra detail D_W

I was looking at CBN wheels that would fit the grinder linked above - this one - and can't seem to find any 200 x 20 x 16mm wheels 'on the shelf'. Axminster have wheels of similar sizes, but the closest seems to be 200 x 32mm.

I did email a couple of firms who have replied asking if I wanted one made to order, and what grit/concentration/rim/grade I'm after..

I feel a bit of research coming on!

 

[D_W]

Thanks for the extra detail D_W

I was looking at CBN wheels that would fit the grinder linked above - this one - and can't seem to find any 200 x 20 x 16mm wheels 'on the shelf'. Axminster have wheels of similar sizes, but the closest seems to be 200 x 32mm.

I did email a couple of firms who have replied asking if I wanted one made to order, and what grit/concentration/rim/grade I'm after..

I feel a bit of research coming on!

They have to be very accurate or you just get a slight bounce of the chisel and cutting only on a portion of the wheel. this happens a lot on regular wheels not properly trued, but over time you can get them into true with use.

For CBN, you can get an odd sized wheel if you can get a properly made bushing, or if you have a lathe, you can make a metallic or corian bushing.

I think it's best to get a pre-made wheel made properly if possible, though.

 

[Derek Cohen (Perth Oz)]

Out of interest, anyone got any recommendations for good tool rests and wheel dressing tools?

I have the Tormek tool rests, which is sold as the BGM-100 kit (see above). This is an amazing combination with the CBN wheels on an 8” bench grinder. It requires a little extra time for set up, but once dialed in (and mine has been adjusted just once in 7 years), it produces fool proof grinds at any angle you choose. It also uses any of the Tormek lathe chisel guides, and this increases its versatility.

Regards from Perth

Derek

 

[TRITON]

Clearly this Chap has a spiritual home here
I mean, to the point of drawing it all out on paper. Im not sure if thats good practice or just totally anal

 

[Jacob]

Clearly this Chap has a spiritual home here
I mean, to the point of drawing it all out on paper. Im not sure if thats good practice or just totally anal

42 minutes! 42 minutes too long IMHO.

 

[TRITON]

42 minutes! 42 minutes too long IMHO.

Too long for your attention span Jacob

I'm sure there's a few 10 minute vids out there.

 

[Jacob]

Too long for your attention span Jacob

I'm sure there's a few 10 minute vids out there.

No just too much flattening nonsense.
Shouldn't take 42 minutes to show how to sharpen a chisel, which normally takes about 30 seconds.
How on earth did they manage before the flattening of chisels was discovered?

 

[D_W]

No just too much flattening nonsense.
Shouldn't take 42 minutes to show how to sharpen a chisel, which normally takes about 30 seconds.
How on earth did they manage before the flattening of chisels was discovered?

This must've been before 1875, as even holtzapffel mentions keeping stones and tools flat for fine work.

The three stone lapping method is probably new, but rubbing two stones together isn't, and someone with reasonable skills can manage two stones to keep both flat.

labor intensive process isn't needed to keep things flat.

 

[Jacob]

This must've been before 1875, as even holtzapffel mentions keeping stones and tools flat for fine work.

Yes but not the modern sharpeners obsessive degree of flatness only possible with diamond stones. etc etc

The three stone lapping method is probably new, but rubbing two stones together isn't, and someone with reasonable skills can manage two stones to keep both flat.

Somebody with reasonable skills can keep a stone flat enough, for life, merely by spreading the work load over the whole surface.
But a hollowed stone comes in handy for cambering blades anyway.
The three plate flattening method was developed by Whitworth in the 1830s and was key to precision engineering. Flatness (manufacturing) - Wikipedia
He lived and is buried just up the road from me (Darley Dale) but moved around and interestingly also worked for Holtzapffel & Co at one stage.
Luckily precision engineering is not needed for woodwork hand tools, but the idea seems to have deranged a whole generation of woodworkers and driven them insane!