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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

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

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

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

Your measurement of the SVM-140 offset of 1.5mm is equally appreciated.

"Trust, but verify"

Rick

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

Rick

You might look at wootz's "Knife Jig Solution"... see if there's a tip in there that will correct the asymmetry.  (I think this is what Rick is referring to).

"Your miles may vary"

Very interesting and informative thread.  Anyone interested in keeping the bevel width on each side of the blade as uniform as possible should study it (not just read it).  Interestingly, at least to me, I noted that Wootz refers to the offset from centerline as being 1.25mm.  Being curious, I disassembled my SVM-45 and started making measurements.  I tried several ways of making the measurements, mostly indirect.  But, finally, I realized I could make just three very direct measurements, using a very accurate and precise micrometer to come up with the numbers to compute the offset.  I worked in inch measurements and converted to mm. 

Measurement 1: Thickness of the Flat.

The fixed jaw on my SVM-45 is very flat and uniform near the transition from the shaft to the flat, offering two opportunities for good measurements.  I measured the thickness of the flat, from the back to the face (towards centerline).  0.352" (first photo).

Measurement 2: Thickness from the back Flat to the Top of the Shaft.
0.629". (second photo).

Third Measurement: Diameter of the Shaft.
0.471".  Important dimension is the radius, not the diameter, so  0.471 / 2 = 0.2355" (third photo)

Calculation:
Distance from the top of the shaft to the front face of the flat.
0.629 - 0.352 = 0.277"

Offset from centerline:  Difference between distance from the top of the shaft to the flat and the radius of the shaft:

0.277" - 0.2355 = 0.0415"  This converts to 1.054mm.  This is the offset from centerline, as measured on my very recently purchased SVM-45. It occurs to me that 1) these are castings (albeit precision ) and they vary, 2)  production process, including patterns change, so through time, you cannot rely on one person's measurement of one jig.

The take-away for me is that, anyone who is going to take things to this level of detail/precision should probably measure their own jigs, so as to determine for themselves, exactly what the offset from centerline they are dealing with.  It is very easy to do if you have a caliper or micrometer, and I would guess that anyone attempting to achieve the symmetry discussed would have these tools. 

It goes for different jigs as well.  I measured my SVM-140 and found the offset to be 1.5mm. 

Rick

CB and Rich,

Thanks Guys.  I am aware of that process, just haven't been using it.  Didn't know it skirts around the size limit, but it makes sense as the image is probably being viewed off the remote website.

Rick

Well, one thing for sure. You do not need help on how to post pictures! Great shots. There are many on this site that have a problem with that.

Actually, he may need some help.  Or maybe I do.  I don't know how he got those pictures to upload, given there is a size limit of 256kb (or so).  The first photo posted, when saved to my computer is 492kb and 1600x1200 pixels.  Given those numbers, the photo is so huge, we only see half or less of it.  Below is the same photo that I saved by download and resized to 640x480 and is 105kb.  It shows the whole machines, not just the left side and honing wheel. 

This is not a criticism, just an observation and comment.  I, for one, would like to know how to post an image so that it shows full size rather than a thumbnail that must be clicked on to view effectively. 

Rick

You might look at wootz's "Knife Jig Solution"... see if there's a tip in there that will correct the asymmetry.  (I think this is what Rick is referring to).

Asymmetry is what I was talking about and if I'd seen Wootz's post, I wouldn't have bothered, just referred to it.  I haven't read the post yet (entertaining granddaughter this AM), but I will with great interest.  Using a set of feeler guages is brilliant; very cheap and readily available.  My point, in part at least for the blade under discussion, was that the blade offset was slight enough as to not be the source of the asymmetry in the bevel width difference.  Perhaps after reading the post, I'll think differently.

Rick

Actually, my multi-tool is TTi. It is almost the same product as Wave. But if you look closely, the grinding is a bit different. The flat side is a little narrower. So it isn't fixed properly on the jig.

I have two SVM-45, but all have the same problem. I think the thumb hole is the cause.

Sharpco,

"the flat side" of what?  The jig or your knife blade?  If referring to the jig, I would call the flat side the "fixed" jaw and the side with the thumb screw the "movable" jaw.  The movable jaw is recessed about 0.5mm deep to about 15mm in from the leading edge.  At first glance, give that the unsharpened spine on my knife blade is about 2.4mm thick, I thought that would cause and offset of about 0.7mm from the actual centerlined of the jig and I thought that might lead to a slight difference in the width of the two beveled sides. 

But, if you look closely at the parting line (of the mold) along the SVM-45 shaft, you can see there it shifts a bit from the centerline of the shaft to the flat blade of the fixed jaw.  That shift results in an offset of the flat part of the fixed jaw of about 1mm.  For a blade like mine, that offset puts the centerline of my blade about 0.3mm off from the centerline of the jig (shaft).  I'm sure this is something that was carefully engineered by Tormek to try to accommodate the wide range of knife thicknesses the jig will see. If that is enough to cause the widths of the grind on each side to be substantially different, I'd have to have some with a lot more experience than me show how much difference it makes.

Maybe Jan, with his trig. and geometry could demonstrate it graphically. 

If I misinterpreted what you mean by the flat side, I've just gone on a interesting (at least to me) goose chase.  If you mean your blade has a flat side, without thinking about it much, I would expect difference in the grind width. 

Rick

Dunno.  Maybe it was due to not knowing any better, but I sharpened my two Leatherman Waves using the SVM-45.  These were some of the first knives I sharpened and I'd probably to a better job now.  I messed the tip up on one and the bevel width is wider towards the tip.  Given the reading I've done since, I'm sure that was due to poor technique. 

I'm not sure if it is a ricasso, but the blade has a narrow unbeveled section (~4.5mm wide x ~52mm long and 2.5mm thick) along the back edge of the blade. 

As I have mentioned in a couple of my posts, part of my motivation for getting a Tormek was realizing that the guy that I had taken my Wave to for sharpening several times was doing it on a Tormek using some sort of jig.

Rick

In my opinion the reason why the countersinks do no cut well may be absence of sufficient relief behind the cutting edges. Similarly to drill bit, countersink cutting edge must have a relief angle also (typically 5 to 8°). Relief behind the cutting edge has even to be slightly larger and must continue around the "conical" surface segment of the countersink's tip. Strictly speaking it is not an exact right cone!

Jan

Hello Jan,

Any idea how a relief angle can be achieved? I have no idea (yet).

Serge

Serge, in my case there was some play in the jig, so it was sufficient to apply more pressure behind the cutting edge.

In your case the jig play is probably much smaller and so you can proceed similarly as when grinding a secondary facet on a drill bit. It means you enlarge the clearance angle by some 10 degrees and grind off segment of the "conical" surface behind the edge. It may be necessary to repeat this procedure for larger countersinks.

Use the marker, blacken the whole countersink surface and make a test countersinking. If the marker is removed from the conical surface you need to remove more steel here.

Jan

I didn't really follow the above conversation.  But, I believe what you need is some sort of cam that guides the countersink in that conical path, although it is a gradually changing conical shape and needs to continue for around 270 deg. in the case of a single fluted countersink.  This is how Drill Doctor does it (see photo) (except the DD photo shows a cam designed for a two fluted drill, so it is much shorter.

Rick

This makes sense to me.  By changing the stop or microadjust, you are changing the orientation and position of the USB and jig, but maintaining the bevel angle.  It makes sense that the LOC would change on the wheel.  If it didn't, you wouldn't have the same bevel angle.

Rick

My writing wasn't very clear... what I meant was, there was a difference between the 2 20° LOCs lines.  (See attached pic.)

That is how I took your statement(s). It still makes sense to me, IF, you are saying even thought the LOC differs for the two 20 deg knives, their angles are in fact still both 20 deg. 

Rick

Rick, thanks for the picture of a nice old radial drill press!

I hoped my could enable some simple milling work also, but thanks to the many degrees of freedom the construction is not sturdy enough.

Jan

Jan,

And depending on the way the chuck mounts to the spindle, a very bad idea.  If it is a taper mount without a screw that holds it in place (very common), with side thrust from milling, the chuck could come flying off the taper.  Drill presses are just not made for milling... 

For a number of years, I did a whole lot of good work on this type of mill:
http://www.grizzly.com/products/Mini-Milling-Machine/G8689?utm_campaign=zPage&utm_source=grizzly.com

Rick