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In the Shop => Knife Sharpening => Topic started by: wootz on March 16, 2016, 08:05:43 pm

Title: Knife Jigs Solution
Post by: wootz on March 16, 2016, 08:05:43 pm
This is to solve annoying bevel asymmetry.
Jig #1 - up to 3mm thick knives.
Jig #2 - for 3-4mm thick knives.
Jig #3 - for 4-5mm thick knives.
Jig #4 - for 5-7mm thick knives.

For centering knives in the jig I use blades from a Feeler Gauge with 1cm wide blades as shims, as explained below.

(http://home.exetel.com.au/dropbox/KnifeJigs_.JPG)

Tormek Knife Jig SVM-45 has 1.1mm spacing from the centreline of the handle to the bottom of the knife clamp (the static part of the clamp) - thanking Jan for the exact figure.
Ideal for 2.2mm knives, but well acceptable for 2-3mm thick as well.
Knives thinner than 2.2mm will get the top bevel higher, whereas knives thicker than 2.2mm will get the base bevel higher; the further from the ideal 2.2mm thickness, the more noticeable is the bevels asymmetry.

For knives 2mm and thinner I use shims.
Measure thickness of the knife at the clamping spot, and divide by 2 - you get spacing to the centreline of the knife.
Difference between 1.1mm and halved blade thickness is filled with a shim.
Shim is placed on the bottom jaw (the static part of the clamp).

Example
Knife thickness 1.7mm, divided by 2 = 0.85mm.
1.1mm - 0.85mm = 0.25mm shim.

Obviously, for knives thicker than 2.2mm you cannot put shims in the standard SVM-45 - for them I use second jig where I ground away 0.5mm from the static clamp.
Spacing from the centreline of the handle to the bottom of this jig is 1.1mm + 0.5mm = 1.6mm
Ideal for 3.2mm knives, but well acceptable for 3-4mm thick as well.

Third jig with 1mm ground off the static clamp.
Spacing from the centreline of the handle to the bottom of this jig is 1.1mm + 1mm = 2.1mm
Ideal for 4.2mm knives, but well acceptable for 4-5mm thick as well.

Example
Knife thickness 3.9mm, divided by 2 = 1.95mm.
2.1mm - 1.95mm = 0.15mm shim.

Fourth jig is adapted Triton Long Knife Jig with 3mm ground off the static clamp. Triton jig has no offset.
Spacing from the centerline of the handle to the bottom of this jig is 3mm.
Ideal for knives 6mm thick at the spine, but can be used for 5-7mm thick as well.

Shim is always placed on the bottom/stationary jaw.



Title: Re: Knife Jigs Solution
Post by: Ken S on March 16, 2016, 10:14:38 pm
Clever, Wootz. This makes a good jig more versatile.

Ken
Title: Re: Knife Jigs Solution
Post by: Jan on March 17, 2016, 03:47:43 pm
Another great job, Wootz, congrats!  :)

You have brought the modification of the knife jig to perfection. It is really a professional set of knife jigs for all possible knife blade thicknesses.

Jan
Title: Re: Knife Jigs Solution
Post by: Ken S on March 17, 2016, 04:08:52 pm
Well stated, Jan.

Ken
Title: Re: Knife Jigs Solution
Post by: SharpenADullWitt on March 17, 2016, 06:36:19 pm
How did you grind them so precisely?
Do you have some other sort of marking on them, so you don't accidently grab the wrong jig (since you have so many)?
Title: Re: Knife Jigs Solution
Post by: wootz on March 17, 2016, 06:49:59 pm
I had them ground for me at a machinery shop.
Title: Re: Knife Jigs Solution
Post by: Ken S on March 17, 2016, 09:42:22 pm
We should make more use of good machinists. I had a machinist modify my Omnijig (dovetail routing jig). That increased its versatility manyfold.

Good show, Wootz!

Ken
Title: Re: Knife Jigs Solution
Post by: wootz on March 17, 2016, 10:17:46 pm
BTW the machinist told me the Triton jig material and accuracy is "utter crap" compared to Tormek's.
I resorted to Triton's only because it is thicker, allowing to grind off 3mm.
Title: Re: Knife Jigs Solution
Post by: Ken S on March 18, 2016, 12:57:28 am
Wootz, if your machinist is impressed with the metal of the knife jigs, he will be blown away with the new zink jigs. It's just my opinion, but I believe most of the jigs will utilize zink in the next very few years.

Ken
Title: Re: Knife Jigs Solution
Post by: wootz on May 29, 2016, 12:44:20 am
Knives with flat-sided wedge profile require more adjustment.
I noticed that sharpening flat-sided wedge knives I don't get equal bevel on sides even if the knife is 2.5mm thick in the original SVM-45 jig: theoretically I should be getting even bevel on each side, but it wasn't unusual to get 0.2mm difference in the bevel height between sides. You could see the asymmetry and it was damn irritating.
Then I realised that because sides of these knives aren't parallel at the back, the jig clamps the blade only at the very spine, and the blade plays even if clamped tightly and during sharpening moves from the centred position (rolls to one side).

Shims pushed from the edge between the blade and jig top and bottom jaws help to center the blade relative to jaws.
In the pictured example I used 0.004 inch (0.1mm) shim on each side, with perfect result.

(http://home.exetel.com.au/dropbox/flat-sided_wedge_profile1.JPG)
(http://home.exetel.com.au/dropbox/flat-sided_wedge_profile2.JPG)
(http://home.exetel.com.au/dropbox/flat-sided_wedge_profile3.JPG)
Title: Re: Knife Jigs Solution
Post by: angpanday on October 10, 2016, 11:41:49 am
Third jig with 1mm ground off the static clamp.
Spacing from the centreline of the handle to the bottom of this jig is 1.25mm + 1mm = 2.25mm
Ideal for 4.5mm knives, but well acceptable for 4-5mm thick as well.

Taking off a 1mm from the static clamp. Does it mean .5mm to be machined off on per side?
Title: Re: Knife Jigs Solution
Post by: Jan on October 10, 2016, 01:16:22 pm
No, you always take off the metal only from the inner side of the static clamp. In this case you ground off 1 mm from the static clamp while the adjustable clamp remains unchanged. 

The small screw of the knife jig enables to adjust it to fit the spine thickness of the knife. No material is removed from the adjustable clamp. ;)

Jan
Title: Re: Knife Jigs Solution
Post by: Ken S on October 10, 2016, 04:45:30 pm
I would have some unsupported reservations about deepening the groove in the ststionary jaw. My concern would be structural integrity, however, these reservations may well be unfounded. Realistically, the Tormek operates at 90 or 100 rpm. I don't think there is a safety issue, even in the unlikely event that the jaw should fail. Worst case scenario, a new jaw or jig is not expensive. I would give it a go.

I would size the depth of the groove to match your piece of steel exactly. Measure the thickness of your steel and halve that thickness.

Do keep us posted.

Ken
Title: Re: Knife Jigs Solution
Post by: wootz on October 14, 2016, 11:41:49 am
The pictures show that grinding the stationary/bottom jaw won't weaken it thanks to the wedge profile.


(http://home.exetel.com.au/dropbox/Jig_grind1.JPG)
(http://home.exetel.com.au/dropbox/Jig_grind1zoomed.JPG)
(http://home.exetel.com.au/dropbox/Jig_grind2.JPG)
Title: Re: Knife Jigs Solution
Post by: Jan on October 14, 2016, 01:03:30 pm
Wootz, thank you for posting the detailed pictures of your modified knife jig. I guess from the shown static clamp 0.5 mm was ground off.

Regards
Jan
Title: Re: Knife Jigs Solution
Post by: wootz on October 14, 2016, 01:35:41 pm
Hi Jan,
The pictured is 1mm off, and it is not the latest slim knife jig.
I can't say if it would be possible to grind 1mm off the thinner jaw in the new version of the jig.
We haven't got them here in Australia yet.
Title: Re: Knife Jigs Solution
Post by: Ken S on October 15, 2016, 09:45:20 pm
Wootz,

Do not despair. The longboat left Sweden two weeks ago. With favorable winds, you should have one soon.  :)

Ken
Title: Re: Knife Jigs Solution
Post by: wootz on October 16, 2016, 07:29:06 am
Ken, how is it possible that you can be so hilarious and helpful at the same time?
Title: Re: Knife Jigs Solution
Post by: Ken S on October 16, 2016, 03:24:00 pm
A little levity helps lubricate the serious work to be done.  :)

Ken
Title: Re: Knife Jigs Solution
Post by: RickKrung on November 27, 2017, 05:52:03 am
Tormek Knife Jig SVM-45 has 1.25mm spacing from the centreline of the handle to the bottom of the knife

Cross posting some discoveries I made today about the offset from centerline of my SVM-45 and 140

https://www.tormek.com/forum/index.php?topic=3445.msg21498#msg21498

Rick
Title: Re: Knife Jigs Solution
Post by: wootz on November 27, 2017, 06:29:03 am
I take occasion to wholeheartedly thank Rick for his measurements of the new SVM-45 knife jig.

The old Tormek Knife Jig SVM-45 has 1.25mm spacing from the centreline of the handle to the bottom of the knife clamp.
The new thinner Tormek Knife Jig SVM-45 has 1.054mm spacing from the centreline of the handle to the bottom of the knife clamp.

The old SVM-45 knife jig gives ideally symmetric bevels on the blades 2.5mm thick at the spine;
while the new SVM-45 knife jig gives ideally symmetric bevels on the blades 2.2mm thick at the spine.

Simpler than shims method is putting on the spine at the clamping site layers of cloth tape to match the ideal thickness. After a few trials, I found that the Norton Bear 50mm cloth tape is best for that (and also protects the blade from scratches left by the jig jaws).
Title: Re: Knife Jigs Solution
Post by: RickKrung on November 27, 2017, 06:44:40 am
You know what grinding marks look like...  Those are end mill cutter marks.  That is how I would have machined your jig, if I were the one you brought it to. 

Rick
Title: Re: Knife Jigs Solution
Post by: wootz on November 27, 2017, 07:12:15 am
The lesson learned today is measure your own jigs offset using Rick's clever method
https://www.tormek.com/forum/index.php?topic=3445.msg21498#msg21498 (https://www.tormek.com/forum/index.php?topic=3445.msg21498#msg21498)
Title: Re: Knife Jigs Solution
Post by: wootz on November 27, 2017, 07:50:17 am
@RickKrung
Rick, you are a bloody genius.
I've remeasured all the jigs I have using your method and had to correct offset for each.
My bevels should be perfectly symmetric from now on.
Title: Re: Knife Jigs Solution
Post by: Jan on November 27, 2017, 09:07:11 am
I have to add my 0.02.

Based on my measurements the newer (zinc) knife jig the offset is 1.0 +/- 0.2 mm. https://www.tormek.com/forum/index.php?topic=2577.30

The large uncertainty in the offset estimation lead me to estimate the value by a deductive way.
 
I have assumed that the Small Knife Holder works symmetrically with respect to flip. Because the steel guide bar (1) of the Small Knife Holder has a thickness of 2.5 mm, I have deduced that the jig offset is 1.25 mm.
https://www.tormek.com/forum/index.php?topic=2577.msg15232#msg15232

Correctness of my value 1.25 mm was not confirmed by Tormek.

Jan
Title: Re: Knife Jigs Solution
Post by: wootz on November 27, 2017, 09:51:53 am
I can only rebuke myself for forgetting that assumptions is the mother of all f*ckups.
Rick's method to measure knife jig offset has eliminated guesswork completely.
Title: Re: Knife Jigs Solution
Post by: cbwx34 on November 27, 2017, 02:05:45 pm
Thanks for all the work and update.

But this thread really shows the need for a self centering clamp.  :o

Hopefully Tormek is paying attention... and will come out with one, like many of the other clamped sharpening system have....  ::)

(... and fix that crazy wide jig stop too).  8)
Title: Re: Knife Jigs Solution
Post by: Jan on November 27, 2017, 02:15:59 pm
Rick, attached there is an image of the static knife jig clamp. The surface is not planar. One feature is the threshold denoted C. Other features are the two very slightly raised strips denoted as A and B. The area D between those stripes is below the level of the point E! (I am describing a new zinc jig.)

What we really need is to measure the spacing between the centreline of the jig shaft (at a place where there is the jig stop, not at a point E) and the slightly raised strip A or B near the bottom of the knife clamp.
 
To make such measurements reliably and repeatedly was beyond my limited possibilities and that was the reason for my adoption of the spacing 1.25 mm.

Jan
Title: Re: Knife Jigs Solution
Post by: RickKrung on November 27, 2017, 05:03:47 pm
Rick, attached there is an image of the static knife jig clamp. The surface is not planar. One feature is the threshold denoted C. Other features are the two very slightly raised strips denoted as A and B. The area D between those stripes is below the level of the point E! (I am describing a new zinc jig.)

What we really need is to measure the spacing between the centreline of the jig shaft (at a place where there is the jig stop, not at a point E) and the slightly raised strip A or B near the bottom of the knife clamp.
 
To make such measurements reliably and repeatedly was beyond my limited possibilities and that was the reason for my adoption of the spacing 1.25 mm.

Jan

Jan,

I agree, mostly.  Using a straight-edge, it appears to me that points A and B are on the same plane as the whole surface between C and E.  It appears to me that the area between A, B and C is recessed, making A and B appear to be raised.  I will use my surface plate and height gauge to confirm or refute this later today.  Using my micrometer, I have already confirmed the area between C and E is the same thickness, 0.353", at least within +-0.001".  I will have to rest the jig on parallels as there is a raised "Tormek" logo on the back of my jig.

To be continued...

Rick
Title: Re: Knife Jigs Solution
Post by: kwakster on November 27, 2017, 05:14:39 pm
Thanks for all the work and update.

But this thread really shows the need for a self centering clamp.  :o

Hopefully Tormek is paying attention... and will come out with one, like many of the other clamped sharpening system have....  ::)

(... and fix that crazy wide jig stop too).  8)

Exactly what i've been thinking for years now.
Sometimes i think i have to buy a KME knife clamp and modify that for use on the Tormek.
Title: Re: Knife Jigs Solution
Post by: RickKrung on November 27, 2017, 05:21:23 pm
Correctness of my value 1.25 mm was not confirmed by Tormek.

Jan

It would be most helpful if Tormek would chime in here with their design offset values, rather than us trying to reverse engineer them.

Rick
Title: Re: Knife Jigs Solution
Post by: cbwx34 on November 27, 2017, 06:15:17 pm
Thanks for all the work and update.

But this thread really shows the need for a self centering clamp.  :o

Hopefully Tormek is paying attention... and will come out with one, like many of the other clamped sharpening system have....  ::)

(... and fix that crazy wide jig stop too).  8)

Exactly what i've been thinking for years now.
Sometimes i think i have to buy a KME knife clamp and modify that for use on the Tormek.

If you haven't already seen... have done just that.

(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=1318)

Takes little more than rearranging the parts and adding a small washer to pivot on (and maybe that top nut, can't remember if it was already on the KME).

Not perfect, but works well (better than the Tormek Jig in most cases)... definitely a step in the right direction, IMO.   ???
Title: Re: Knife Jigs Solution
Post by: RickKrung on November 27, 2017, 07:38:46 pm
Rick, attached there is an image of the static knife jig clamp. The surface is not planar. One feature is the threshold denoted C. Other features are the two very slightly raised strips denoted as A and B. The area D between those stripes is below the level of the point E! (I am describing a new zinc jig.)

What we really need is to measure the spacing between the centreline of the jig shaft (at a place where there is the jig stop, not at a point E) and the slightly raised strip A or B near the bottom of the knife clamp.
 
To make such measurements reliably and repeatedly was beyond my limited possibilities and that was the reason for my adoption of the spacing 1.25 mm.

Jan

I can appreciate that.  I do have the ability to measure accurately, so here is what I found.

I measured the height of the several points on the flat side of the fixed jig jaw using a precision height gauge that reads at 0.001".  I placed the jig on its back side on parallels on a precision granite surface plate.  First, I stoned the parallels and measured them.  They were about 0.0005" different, the narrower one was placed under the front of the jig jaw (on the right in the photos). 

Zooming in on the height gauge in the photos below and referring to Jan's location callouts, point E measured 0.499" ("zero" on the gauge is the center of the set screw hole, which would be 0.500" in this case).  The height gauge could not reach point C, so I measured a point about equa-distant between point E and A, measured 0.499".  Point A measured 0.498".  Point D measured 0.4895", but I'll call it 0.490", about 0.008" - 0.009" lower than E, E-A and A.

I further checked the recess (area "D") with a feeler gauge - 0.010" went in, but 0.011" did not. 

I also measured seven locations of the flat with my micrometer (Mitutoyo, reads to 0.00005" with an uncertainty of measurement of 0.000044", according to the Certificate of Inspection)  The values ranged from 0.35185" to 0.35245".  Point E was 0.35145", Locations E-A and E-B were 0.35220". Rounding to the nearest 0.0001" there is a range of 0.0007" difference of the flat surface.  Pretty dang good for a casting and every single one will be different.  We can all come to our own conclusion on where to measure the thickness while attempting to determine the magnitude of the offset. 

Rick
Title: Re: Knife Jigs Solution
Post by: wootz on November 28, 2017, 12:12:44 pm
Rick, and again thank you so much for your time and all that hard work you do for us.
The fact is that your last measurements have added precision to my jigs offset estimation.

Our jigs static part is polished to the recess, designated as D in this thread

Tormek knife jig out of the box (right) compared to ours.
(http://knifegrinders.com.au/Procedures/P_jig.JPG)

Calculations of the offset by your method are done at the point E
Your estimation that the recessed area (point D) is lower than the point used for the offset calculation (point E) by about 0.008" (0.2mm) has added precision to our jigs offset number.

For example, having calculated the offset of my jig by your method as 1.1mm, at the recessed area that is actually clamping the blade spine it will be by 0.2mm lower, i.e. the true offset is 1.3mm

This doesn't apply of course to unchanged jigs.
Title: Re: Knife Jigs Solution
Post by: Jan on November 28, 2017, 01:00:45 pm
Rick, thank you very much for posting the important results of your measurements! You have done a very good job.  :)

I have a question. When you calculate the spacing, do you assume that the centreline is parallel to the plane in which the flat side of the fixed jig jaw is embedded? 

Wootz, thanks for your values.

Jan
Title: Re: Knife Jigs Solution
Post by: RickKrung on November 28, 2017, 05:36:23 pm
Wootz, yes, I concur with your estimation of the offset of your polished jig as being 1.3mm.  I recall someone saying they were concerned about the jigs causing scratches on their customer's knives.  Is that the reason for polishing the jigs?

Jan, yes, I do assume it is parallel, but as I've said, "trust but verify".  I did look at it.  I held a straight edge on the flat and examined how it lined up with the parting line on the shaft.  It appeared very much parallel. I also examined how "flat and parallel" the surface of the flat appeared and it did appear that way.  If it wasn't, all those fancy measurements would not have meant much. 

And thanks, both for your thanks.  Why to I do to such extremes?  It is like dogs...  Why to dogs lick their ...   Because they can... 

Rick
Title: Re: Knife Jigs Solution
Post by: Jan on November 28, 2017, 09:39:32 pm
I am happy that the spacing value 1.30 mm is very near to my value 1.25 mm deduced without any measurements!  :)

I am firmly convinced that Tormek was also guided by the symmetry requirements when designing the Small Knife Holder with the 2.5 mm thick guide bar.

The symmetry concept is the most powerful tool of today's physics. It is almost evident the all laws of nature have origin in symmetries. May be it is guiding principle of the universe.  ;)

Jan
Title: Re: Knife Jigs Solution
Post by: wootz on November 28, 2017, 10:36:14 pm
Yes Jan, I also found it amazing that the offset to the recessed area in the older version of the knife jig is practically the same 1.25mm we've been using.

However, being honest to ourselves, the real offset in unchanged jig, which is clamping at those raised borders that you designated as A and B is 1.1mm and we unwillingly introduced asymmetry in our attempt to eliminate it.

I understand very well the purpose of those raised borders - they facilitate clamping of a tapered spine.
But unfortunately they are also the main source of scratches left on the blade, and that made me grind and polish them off.
Title: Re: Knife Jigs Solution
Post by: RickKrung on October 05, 2018, 08:55:39 pm
Resurrecting another old thread, but one which has great value and utility, if one is inclined to go so far...

Ever since first reading of Wootz's modifications to the SVM-45 Knife Jigs to address problems with asymmetry of the resultant bevel widths, I had been wanting to do the same.  But I only had two -45s and not enough "need".  Since starting with the farmers market work, I was sharpening knives of varying width, but none over about 4mm (0.157") (or if greater, I ignored it).  But...  This week, a customer returning for the third time brought two HUGE hunting knives, one an incredible work of Damascus steel art that looked to be 5-6mm thick.  I had already decided to take the plunge and had just received the day before, two more SVM-45s and another SVM-140, so that I could mill the recesses (0.5 and 1.0mm) on the fixed jaws of two of the -45s, so I had to tell the customer to bring his beautiful knives back next week when I would have the right jigs to deal with the blade thickness. 

I have just completed milling the recesses on the two -45s and am very pleased with the results.  Also, in preparation, I had ordered and received two SS feeler gage sets, labeled in both inch and MM.  I cut down one set for use with the -45s and saved one set full sized for use with larger knives and the -140s. 
(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=2704)

I wanted four -45s and two -140s so that I could mount six knives at once and run them all through one stone/wheel at a time before having to change knives in jigs, so I really needed the modified -45s to be usable with thinner knives as well as thicker ones.  I developed a spreadsheet giving the shim thicknesses needed for various thicknesses of knife spines.  I initially worked it up in 0.001" increments, but for brevity and functional utility at a farmers market bench, summarized it into 0.005" increments (~0.13mm).  I figured +-0.005" is close enough and definitely much better than no compensation at all.  (A PDF of the shim chart is attached below)
(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=2706)

The images below show a "thin" knife 0.062" (~1.6mm), that fits in an unmodified jig (Jig#1) and the shims needed for both Jig#1 and Jig#2.
(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=2710)

(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=2708)

I have used Jigs #2 and #3 for sharpening two large hunting knives (very cheap Schrades) that I bought a long time ago to practice sharpening long and thick knives but had never touched until now.  Results are excellent with bevels from side to side being so identical that I cannot discern any difference.  My bevels are still wider at the tip than in the straight body, but that is a lacking in my technique, not with the modified jigs. 

One happy puppy.  Thank you Wootz for the inspiration. 

Rick
Title: Re: Knife Jigs Solution
Post by: Jan on October 06, 2018, 10:24:03 am
Rick, in my understanding your chart was calculated assuming that the Tormek knife jig works perfectly for 0.1"spine thickness. Correct?

When I have to use shim(s) I often have difficulties to mount the blade in the knife jig symmetrically, so that the bevel angles are the same for both sides. The shim slides on the blade and makes the montage difficult. Do you have some trick how to overcome it?

Jan
Title: Re: Knife Jigs Solution
Post by: wootz on October 06, 2018, 01:51:52 pm
Dr. Werner N. from Germany shared his shim holding with us:
"When I need a shim I use two small but strong Neodymium magnets to hold the shim in place, still being able to move it around. After I clamp the knife and shim I remove the magnets."
(http://knifegrinders.com.au/photos/Holding_shim.jpg)

I use shims when the blade has a wedge profile, otherwise use layers of cloth tape to bring the clamping site thickness to the ideal for the given knife jig.

Dr. Werner also shared his other gimmicks, e.g. for setting the grinding angle with our applet he advised the depth caliper as on the photo, and we use them now.
(http://knifegrinders.com.au/photos/depthcaliper.jpg)

Title: Re: Knife Jigs Solution
Post by: RickKrung on October 06, 2018, 04:29:08 pm
Rick, in my understanding your chart was calculated assuming that the Tormek knife jig works perfectly for 0.1"spine thickness. Correct?

When I have to use shim(s) I often have difficulties to mount the blade in the knife jig symmetrically, so that the bevel angles are the same for both sides. The shim slides on the blade and makes the montage difficult. Do you have some trick how to overcome it?

Jan

Jan,

Yes, that is correct, 0.1" spine thickness.  I wasn't thinking of it exactly like that, rather 0.050" offset of the fixed jaw from the jig centerline, but that is the same. 

I've only used shims on a dozen knives since modifying the jigs.  I have not had much trouble with the shims sliding.  I insert the knife with the fixed jaw up and then slide in the shim and snug it so the knife can still move slightly.  Turn it over and use your (I think) projection template for positioning the edge perpendicular a tighten.  Then I use a device similar to the one Wootz uses to set the projection, a modified woodworker's marking gauge, which I'll address in response to Wootz's reply. 

Rick
Title: Re: Knife Jigs Solution
Post by: RickKrung on October 07, 2018, 03:02:56 am
Dr. Werner N. from Germany shared his shim holding with us:
"When I need a shim I use two small but strong Neodymium magnets to hold the shim in place, still being able to move it around. After I clamp the knife and shim I remove the magnets."

I use shims when the blade has a wedge profile, otherwise use layers of cloth tape to bring the clamping site thickness to the ideal for the given knife jig.

Dr. Werner also shared his other gimmicks, e.g. for setting the grinding angle with our applet he advised the depth caliper as on the photo, and we use them now.

Nice trick, using magnets.  I had not thought of it as my first reaction is "stainless steel is not supposed to be magnetic" since so many of the knives we deal with are stainless.  I know some stainless alloys have some magnetic response. Are knife alloys of that sort? 

I probably haven't used shims enough yet to recognize the need for shimming to compensate for taper in the knife spine.  I was just happy with this much.  I do have some cut-of shorts of the shim set I trimmed down.  I was wondering what, if anything, I could do with them. 

I really like the projection setting depth caliper idea.  I had found an attachable foot for my digital calipers but didn't really like it. 
(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=2713)

More accurately, I didn't like the flimsiness of the Depth Rod that sticks out from the caliper.  Before finding the caliper foot and what I still use is a pattern maker's marking gauge, that I modified by replacing the cutter with a washer.
(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=2715)

I use calipers to set the marking gauge projection and then use that to set projections of the jigs.  I use only 139mm so it stays set at that and I check it now and then to be sure it hasn't moved. 
(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=2717)

I might have to look into a longer depth caliper, tho.  It might be better for setting the USB height than the marking gauge I currently use (different on than for setting knife jig projections) as it would allow direct setting rather than secondary - setting the gauge then setting the USB height. 

Rick
Title: Re: Knife Jigs Solution
Post by: Ken S on October 07, 2018, 06:48:57 am
I believe the Veritas marking gage uses 5/16” rod for the shaft.

Ken
Title: Re: Knife Jigs Solution
Post by: RickKrung on October 07, 2018, 07:22:39 am
Yes, it does use 5/16".  I do not understand your reason for commenting on it.   ???

Rick
Title: Re: Knife Jigs Solution
Post by: RickKrung on October 11, 2018, 07:51:46 am
...snip...
Dr. Werner also shared his other gimmicks, e.g. for setting the grinding angle with our applet he advised the depth caliper as on the photo, and we use them now.
(http://knifegrinders.com.au/photos/depthcaliper.jpg)

Wootz,

Thank you so very much for posting this method from Dr. Werner.  I liked it before and decided to bite the bullet and get a depth caliper.  I went for digital.  It arrived today and I am very excited.  I really like the wide base and was anticipating using it to help with aligning the caliper relative to the USB top. 
(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=2737)

With my existing method of using a marking gage, I had been wanting some method of keeping the shaft parallel with the USB vertical but had not really come up with anything I liked.  Quite a while ago, I had bought an extra USB but it came without the micro-adjust.  Recently, I ordered four so I would have some extras.  As I set about playing with the depth caliper tonight, and thinking about wanting to keep it parallel, it dawned on me to put a second micro-adjust at the top of the threads and use both as parallel spacers.  Works fantastic. 
(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=2739)

An added beneficial feature of the caliper is the angle or bevel at the foot.  The bevel keeps the foot away from the radius in the casting at the base of the USB mount, allowing the foot to register more accurately on the top of the casting.  The combination of the bevel, the "spacer" micro-adjusts and the wide base makes for nearly perfect parallel alignment with the USB vertical post and perpendicular with the machine case and USB top. 

I tried running the bottom micro-adjust up and down to see what the range of rotation was when the caliper was well lined up.  I was very pleasantly surprised that it was extremely precise.  For example, the wheel landed at almost exactly the same place, for example, just off the left, lower corner of the numeral "1" with very little variance. 
(https://www.tormek.com/forum/index.php?action=dlattach;topic=2962.0;attach=2741)

This is definitely faster and more consistent than my marking gage method.  I am thrilled with this and the fact that using the caliper, setting of the USB height will now be direct rather than indirect. 

Thanks again for the seed on this. 

Rick
Title: Re: Knife Jigs Solution
Post by: wootz on October 11, 2018, 01:37:28 pm
Think you for sharing, Rick. I keep learning from you. Will email Dr. Werner your photo and description.
Title: Re: Knife Jigs Solution
Post by: wootz on October 11, 2018, 10:31:34 pm
Werner's little inventions have the impress of genius, it won't be fair to keep all to myself.
Another gimmick from Dr. Werner - magnetic truing tool (the magnet ball used instead of cable ties)
(http://knifegrinders.com.au/photos/TT-50_Magnetic.jpg)

PS
Dr.Werner is PhD in low energy atomic collisions, and one of our happy German customers, one of very few who knows how to sharpen microtome blades  :o
Title: Re: Knife Jigs Solution
Post by: Drilon on October 18, 2018, 08:29:31 pm
Hello Wootz and Rick, using a second micro-adjust to adjust the caliper is a good idea. Unfortunately it doesn't work with the T7 as the base holding the USB is 1mm too wide in diameter.
Regards,
Drilon
Title: Re: Knife Jigs Solution
Post by: RickKrung on October 18, 2018, 09:19:33 pm
Hello Wootz and Rick, using a second micro-adjust to adjust the caliper is a good idea. Unfortunately it doesn't work with the T7 as the base holding the USB is 1mm too wide in diameter.
Regards,
Drilon

That being true, you apparently cannot use the caliper to set the USB height directly from any given "distance" number, be that from a script like Wootz's or other.  Would it not work to simply adjust that number to compensated for the offset of the USB base? 

Wootz has and uses a T7 I'm pretty sure, as I think I've seen photos of it on his site and in his postings.  He must have a way of doing it as he does use calipers.  I'm sure he will chime in. 

Rick