Messages

I too have noticed that the surface of the stone gets "discoloured". I use good quality water, work on clean tools and keep the T7 dry and covered when not in use. Can it be that I am seeing rust in the surface of the wheel from embedded steel fragments after sharpening HSS bits?

I've tried the dowel wrapped in abrasive paper, suggested on this Forum, and it can work for me on a bread knife.

My honing wheel has settled down without too much of a bothersome bump. But I did need some effort of sanding the join. As has been said, in the sequence of shaping, sharpening and polishing (honing) it is best to finish sharpening with the grinding wheel at its finest grit.

I am pleased to report that I have succeeded in grinding four facets as per instructions and videos! My difficulty was a lack of belief that the narrow width I was leaving for the primary facets would not survive drilling through tough material (jarrah, HSS). The width of the primaries on a 8 mm bit are less than a mm. Having never seen a four facet grind and only familiar with the amount of steel of the primaries on the usual 2 facet grind I had a disbelief problem. On reflection, it is only the leading edge of the primaries that do the cutting, the secondaries are to get unnecessary steel out of the way. So, why not reduce the bearing surfaces of the primaries to a minimum.

Thanks to the Forum and to Stickan for your help.

I would be interested to know the history of the 4 facet grind for drill bits. None of my references mentions it. Any help among the Forum?

Thanks for letting us know about the videos Ken. Great viewing. I hope we get continuing posts from Tormek.

Ken, I presume these are located whenever within a topic. Is this an innovation of the site software? Are there instructions to follow?

Thanks Ken, I like your alternative approach! If I follow you, after I have got near to establishing the four facets, I remove the primaries by over grinding the secondaries and then reestablish the primaries. I like this idea as there would be much less grinding with the primaries as the four facet end point is approached.

I should add that as I look at my last effort on an 8 mm bit in good light (I must do something about that) I have got the cutting edges of the primaries to be just past the centre line - with a lot of grinding. I stopped there because any further advance on the secondaries would have removed the primaries after all my hard work. I will now try Ken's innovative method on this bit!

Thanks to Strachan for the offer of FaceTime help.

I failed again. Working on a 8 mm drill bit, I was unable to get the primary facets to extend past the centre of the bit. Symmetry prevailed, the two primary facets refused to cross the centre. The leading (cutting) edges of the primaries lined-up across the centre of the bit no matter how much HSS I removed. When I grind the secondaries, I continue to get a chisel point of about 1.5 mm. I used a setup of 11 and 118 degrees. Help!

OK, I think I have it! Favourite tipple in hand and another (more) careful read of the instructions and I find on page 10, diagram 6 from the top: "Grind alternatively both the primary facets until they reach over the centre of the drill." This is counterintuitive for me and hence ignored! I did not grind over the centre of the drill. I will follow the instruction and let you know the result. Thanks for your suggestions.

Thanks Stickan, I was beginning to think there were no users of the drill bit jig in the Forum. I have rechecked the videos and the instructions and think I am following the advice. Are you able to get the 4 facets to make a point?

I have used the DBS22 on about 10 bits from 4 to 10 mm. Took me a few hours but getting the hang of it. Now for the but! I can shape the four facets BUT I can't get the primary facets to meet at a point. I can increase the secondary facets so that the primary facets become a narrow strip but a chisel point remains. If I go beyond this then I grind out the primary facets. Where am I going wrong?

Thanks for the helpful replies. I remain surprised with the "moonscape" of the truing tool. If there is a diamond sitting up above all others then the truing is done by this point source. Practically, I will end up with a ridged surface of the grinding stone. Should I routinely follow truing with the smoothing stone?

Thanks for the help. I can confirm that I move the blades across the stone as I sharpen.

I looked at the surface of the truing tool with a 10X lens. It looks odd to me. I expected an even surface with diamonds (?) embedded like sultanas in a pudding. What I see is the embedding surface (copper coloured) in three ridges that run in the direction of travel of the grinding stone. The centre ridge is much higher than the others. The centre ridge has a prominent crystal (is it really a diamond?) that does all the cutting. Consequently the finished surface of the grinding stone has oblique ridges across it that are obvious to my naked eye when the water drains from the surface! Have I got a dud truing surface? The mechanism works well and I have used various speeds of travel.

Drill bits are "HSS". Are they not as hard as the metal lathe tools?

I have spent some time shaping and sharpening chisels and hand planer blades with ok results. I used the supplied stone to refresh and alter the grit of the wheel. I am surprised to find that I seriously altered the shape of the angle of the surface of the stone by my actions. I concluded that the grinding stone is quite soft and I needed to be very careful to apply even pressures to the surface or it quickly wore unevenly. This was identified by putting a set square across the surface of the wheel. I used the truing tool to good effect. A little more shaping and sharpening and the wheel needed re-truing! I estimated that I removed about 3 mm with the truing tool, and the water bath was carrying a lot of suspended grey sediment. At this rate I'll need a new wheel sooner than I expected!

My questions:

Could it be that the the pressure I applied across the surfaces being sharpened was too heavy and uneven?

Can the surfacing stone grind the surface out of square if pressure is applied unevenly?

I was using the square edge jig and it was not good enough to place the right hand side of the blade against the jig and tighten the knobs. I needed to measure with a set square and tighten carefully. Then I needed to ensure that the finger pressure was even across the blade. If not, the the sharpened edge was soon out of square. Is this a correct conclusion?

I assumed that if I was using a jig and a rigid support system then I could set and forget and go at the shaping and sharpening. Is this an unreasonable assumption for any of the Tormek jigs?

PS. I like working with the water cooled system. It may be that when I have my tools in good order and settle down to resharpening then I will have less of the problems I have described.