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a variation of sharpening and freehand honing

Started by Ken S, July 29, 2013, 02:33:47 AM

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Ken S

Obtaining a correct and consistent bevel angle with the Tormek and SE-76 depends on two adjustments:

1) The distance between the grinding wheel and the universal support bar

2) The projection distance of the tip of the blade to the SE-76.

Varying one of these will necessitate compensating with the other to maintain the same angle.

Maintaining consistent distances with both of these will insure consistent, repeatable bevel angles.

The usual Tormek technique involves using the anglemaster and varying the wheel/usb distance to compensate for whatever the blade projection distance happens to be.  While this produces accurate work, it involves needless steps.

The TTS-100 allows more efficient setup for turning tools.  There is no reason the same technique cannot be applied to bench chisels and plane blades.

The wheel/usb distance may be set using several techniques.  Using the "A" distance setting with the TTS-100 provides a very quick, accurate setting.  I happen to have a TTS-100.  This is the method I use.

The method of using wooden set up blocks as described in the Handbook also works well.  This method may also be used in conjunction with the TTS-100 when different spacing might be required for special jobs.

Using a second adjustment nut as a lock nut provides a simple way to "lock" the adjustment.  It is also easily removable for other uses. After adding the second adjusting nut, I have decided to leave it on.  It works very well.  The nut is available from sharptoolsusa.  (US-105N Adjusting nut with scale for universal Support $7.00)

The TTS-100 provides three slots for different projection lengths of turning chisels.  None of these three lengths corresponds to bench chisel length.  What I have done is put a short length of white label tape in one of the slots.  After checking the correct blade projection with the anglemaster, I hold the bottom of the TTS-100 against the SE-76 and mark where the tip of the blade is on the label tape.  That line is identified with the bevel angle.  The same thing may be done with a 3x5 card.  The edge of the card is placed against the SE-76 and the line is drawn and labelled.  Be sure to note the reference edge on the card.

With the wheel/usb distance set and the blade projection checked with the projection gage, future chisel sharpening will have the same bevel angle.

I believe using the leather honing wheel with the tool in the SE-76 jig is an efficient way for most users to remove the scratches left from the fine graded wheel.  I happen to have a second universal support bar, which I leave set up in the horizontal position for the leather honing wheel.

The TTS-100 can be used with the usb and leather honing wheel.  When checking an angle on the leather honing wheel with the anglemaster, be sure to reset the diameter to 220 mm. 

Initially results indicate to me that this spacer adjustment stays consistent when bevel angles are changed.

This allows the blade to be held in the jig for the removal of the scratches from the grinding wheel.  The only need for freehanding is now very light removal of the burr.

For those who do not have a TTS-100, there is a simple workaround.  I cut a piece of plastic conduit to 18mm length. 

First, set the usb distance to the leather honing wheel (not using the plastic spacer).  locking that distance setting, remove the usb from the horizontal support and place it in the vertical support, placing the spacer between the adjustment nut and the locking support on the Tormek unit.  This spacer happens to place the usb distance to the grinding wheel to the same as the distance to the leather honing wheel.

Once these distances are set, adjust only the projection length of the blade to obtain the correct bevel angle. note the projection length with a line on a card.

I realize this may sound complicated.  It is a work in progress.

Ken


mike40

You lost me a little on this one Ken. I was thinking that to replicate a bevel you could just put the chisel into the SE-76 and then use the angle master to set the angle together with adjustment of the USB. That seems very simple and quick to me, given my very limited experience of course. Are you saying that if I grind a 25' bevel on my chisel, that when I set it to 25' for a regrind, that it will actually be different? Or are you trying to eliminate the trial and error method using a permanent marker? I can see that in spite of the set angle on the angle master, that the grinding wheel size might not be precise and therefore cause a slightly different bevel angle between grindings. I am guessing that is why the marker is used. As far as stropping goes, I want to do that freehand if possible for the same reason that Jeff does, so I can easily strop the back without having to take the tool out of the jig.
Mike

Rob

Quote from: Ken S on July 29, 2013, 02:33:47 AM

I use the same TTS-100 "A" setting to start.  Due to the different diameter of the leather noning wheel and the Tormek grinding wheel, the "A" setting is close, but not accurate. 
Ken

I like your method for consistency Ken but I'm not sure you're right about the differences in diameter you mention above.  I thought the whole point of those two little metal alignment circles on the tts-100 was exactly to avoid the issue of differing diameters?  In other words, the tool is deliberately designed to cope with differences in diameter in precisely the manner you describe.  Thus the tts-100 should always deliver the same usb distance from any diameter wheel using the A or B setting
Best.    Rob.

Ken S

Thanks for your responses, Mike and Rob.  Even before I read them I realized I had made an error and needed to modify the post.  I happened to watch Jeff's demo videos on sharptoolsusa.com.  I realized I probably forgot to adjust the anglemaster for the difference in the diameter of the leather honing wheel (220mm).  That may be the culprit for the discrepancy in the TTS-100 settings.  I will check that later this morning when I have access to my shop.

You are correct, Mike, in stating when you use the anglemaster gage the bevel angle will remain constant.  Within useable ranges, any combination of compatible wheel/bar distance and blade projection distance will give the same bevel angle.  My idea was to be able to standardize them in order to eliminate having to reset one with each new tool inserted in the SE-76.  This may turn out to be more of a theoretical gain than something of practical value.

Rob, you point is well taken.  The difference would seem to be a senior moment in forgetting to reset the wheel diameter setting on the anglemaster.

I divide stropping into two operations.  The first is polishing the bevel to remove the scratches from the 1000 grit wheel.  The second is removing the wire edge.  Jeff actually does this in the demo, although he states that with his experience he would do both freehand.  Given his experience, I would probably do the whole operation freehand, as he does.  Most of us, myself included, will never log that many hours on the Tormek.  It seems logical to do as much of the total sharpening operation jigged.  Doing the final bevel polishing in the jig lessens the window of opportunity to round over the edge.

I had no expectations that the original post would be the final copy.  That's why I posted it in the early stages.  It will grow better, either sink of swim, with input from the forum.  I appreciate the input.

Ken

mike40

It's been a good discussion for me Ken, as I learned about what the metal disks do on the TTS-100. I haven' got one yet, so I haven't read up on it.
Mike

Rob

The tts-100 is in fact a remarkably useful tool.  The fact that its design makes it wheel diameter agnostic is a brilliant bit of ingenuity in my view.  I was using mine only this morning during the turning of a cherry bowl...it works amazingly accurately every time.  Just for a laugh I re-set it on the strop and honed....perfect bevel matching without any problems.
Best.    Rob.

RJM


Rob

#7
Aye...sorry RJM, this thread has aimed at the folks with a few years behind the Tormek in the main.  If you're interested in any of the specifics, by all means ask and I'm sure we can de-mystify the explanation a whole lot.

The summary is that Ken is advocating a quick method by which you can set the two variables that govern the angle at which you'll grind your tools bevel.  Those variables are:

- the distance of the support bar from the grinding wheel and...
- the distance the tool "sticks out" from the square edge jig (the SE-76)

If you alter either of those settings it changes the angle you grind at and hence your bevel.

All the acronyms and Tormek specific jig names confuse things but here's a quick glossary:

- SE-76.  Tormeks patented square edge jig for plane and chisel irons
- tts-100.  Tormeks patented woodturning tool setter.  This is useful for setting a uniform distance of the support bar from the grinding wheel.  Another method is to actually make (out of wood typically) a custom spacer block that you hold against the grinding wheel and draw the support bar up to it, thus setting the same gap every time.

It also allows you to quickly repeat three choices of tool protrusion for different bevel grinds.

Hope that helps :-)
Best.    Rob.

Rob

Best.    Rob.

Rob

And here is the SE-76 square edge jig (which you almost certainly already have)

Best.    Rob.

Rob

Here is an annotated diagram of the key features of the tts-100 by way of explanation as to how it's capable of repeating a consistent distance setting from a grinding wheel regardless of its diameter.

Best.    Rob.

Rob

And final diagram shows the reverse of the tts-100 showing the three tool protrusion settings that cater for three "known distances" which correspond to useful bevel angles in bowl gouges or with other jigs for different tools.

Best.    Rob.

Ken S

I have done some further work in this method, and will be modifying my original post to correct for a couple errors and add some new thoughts.  I place this notice here so that readers will not be confused by the earlier posts by Mike and Rob.

Ken