Messages

Jan,
Can you please clarify what you mean by "protrusion"?

Is that the distance from the back of the USB to the stone, or the distance from FRONT of square jig to stone?

Thanks.

Thanks Jan.  I understand Dutchman's tables are outside the range of the square edge jig.

I developed a calculator for use with the square edge jig.  Here is my input:
Wheel diameter = 237.0 mm
Surface of wheel to center of support bar = 19.0 mm
Grinding bevel angle = 25.0 degrees

Here is my output:
Back of support bar to wheel surface = 41.78 mm

The blade projection from the front of jig will have to be determined after I get a good measurement directly from the jig.

As I said earlier, I would hope that I can make a sliding jig that will allow a changing blade projection setting as the wheel diameter changes.  I have a simple prototype in mind that is just a couple of wood blocks with slots and a screw to tighten.  Of course, I don't know how quickly the wheel diameter will change, as I am expecting the original wheel to last many more years.

Thanks for your help.  I can attach my Excel file if you would like.

Steve

Thanks Ken.

I thought about using some trial and error to set the projection (and make a jig), using a fixed support distance from the wheel surface.  However, I know that over time this relationship would change.  Of course, I don't know how long that will take.

My thought was possibly to develop a spreadsheet using Dutchman's equations, specifically for use with the square grind jig.  As you know, there would be a different range of "S" and "A" values with the square grind jig vs the knife jig.  Also, I thought I may as well use the spreadsheet for the range of wheel diameter I will be working in for the realistic future (which is 230 mm to 240 mm).  I could run the spreadsheet for each 1 mm change in wheel diameter.  At this time, I don't know how sensitive cutting bevel is to a slight change in wheel diameter.  But for the level of sharp we all like to chase, I suppose it would be sensitive.  I guess if I get it really close with the set-up, I can do a slight adjustment using the sharpie method before grinding.

I have a lot of ideas floating through my mind right now about how to implement this.  One of them would be to develop an adjustable projection jig, which would allow the projection to be set to the spreadsheet projection values - which would ALL be established for the SAME distance between the support and wheel surface "S).  I could use a spacer block to set the support bar.

I hope that makes sense.  I have to think through the details a bit more. 

I don't have much experience with the machine, so I could be chasing a bad idea.

Steve

I found the excellent threads discussing the Kenjig and Dutchman tables.  It seems the discussions and Dutchman's tables were developed for the knife jig.

I would like to develop some quick-set jigs for plane irons and chisels.  I have the old-style square jig, if that matters.

I don't see any reason why I could not use Dutchman's equations to develop settings for my purpose, but I thought I would throw this out to more experienced users first.

Thanks.
Steve

I bought my Tormek used about 6 weeks ago.  I don't know what was done to the honing wheel before I got it.

Overall I really like the Tormek, but one thing I really don't like at all is the mess from the honing wheel.  Excess honing compound drops from the wheel onto the machine and counter top.  I can wipe that up easily enough.  The worse part of this is seeing dust floating off into the air.  That is the same air I am breathing.

It sounds like if I can get a little bit of oil into my wheel it could keep the dust down.  The trick is just getting a little bit into the wheel.

I am wondering if holding an oil-moistened rag against the rotating wheel could help to transfer just the right amount.  The stories of over-oiled wheels makes me hesitant.

I ended up buying a new USB.  I am glad I did.  I like the threads and the microadjust that was included.  But it also gives me another USB to set up with my grinder, or maybe keep in place for the honing wheel.

I might thread the older USB at some point in the future.

I have really come to appreciate the speed and results I have been getting with the Tormek.  All my chisels, plane irons, and kitchen knives are sharp!

Herman,

It is interesting that you doubt I crowned the stone with the grading stone.  It seems to me that there could be no other explanation.  It was not due to my grinding process (only 2 chisels).  Also, after truing and using my more careful grading procedure, and regrinding the chisels using the same procedure, I did not have any crown troubles.

By poor technique with the grading stone, I think that I inadvertently exterted higher pressure on the outside of the grinding stone when moving the grading stone back and forth, thereby rounding over the outside edges of the grinding stone.

I am working my way through the epic kennyk thread (about 3 pages in so far), and he seems to be convinced that the same thing had happened to him.

I am hoping for a happy ending to that thread.  I don't want to look ahead.  I am hoping to pick up a few lessons along the way.

Steve

Herman,

The "bobbing" I was referring to was the outer cutting surface.  I should stress my observation was very minor.  It did cause me to take a closer look, mostly at the wheel crown - which was fairly significant when holding a straightedge across the cutting surface of the stone.  I am convinced that this is due to my poor technique with the grading stone.

I re-trued the wheel and then used great care to use even pressure when grading.  I did not move the grading stone side-to-side as shown in the instruction diagram.  Because I am still new at this, I am not entirely sure how to know when enough grading is enough.

I sharpened two chisels and honed using the wheel.  I don't know if I was being overly careful not to round over the edge, but I had a hard time chasing off the wire edge.  Even though a small amount of the wire edge still remains, I can cut paper with both chisels.  But not as easily as Steve Farris makes it look.  Maybe thinner paper would help.

Any comments for chasing off that last bit of wire edge?  Perhaps it is steel quality.  One of the chisels is a cheapie.  The other is a Marples made in Sheffield.

One comment I have is that I did not like the look of the dried diamond paste dust floating up into the air as I was honing.  Micron-sized diamonds can't be doing any favors for the lungs.

Steve

Herman,

Thanks for your idea - I might try mounting to a high speed grinder if I can figure out a way to do it.

Last night I tried to sharpen and hone a chisel, even though I know the honing wheel is not round.  I went through the whole grinding process, then honed by hand.  I ended up with a sharp-feeling chisel that would catch my finger nail with no problem. 

After the honing process, with the grinding stone still spinning, I looked at the grinding stone to admire how round I had gotten it with the truing tool.  I could not believe my eyes, but I was noticing a "bob" in the stone it turned, when comparing the outer edge of the spinning stone to a stationary spot on the wall just beyond the stone!

After just one chisel, how could this be?  I put a 6" rule across the cutting surface of the stone.  Apparently, there was also a crown (hight point in the middle) in the stone!  This would result in a negative camber on the tool - and would never be acceptable for a plane iron.  I was discouraged and packed it up for the night.

Since then, it occurred to me that I must have used a bad technique with the grading stone, and rounded over the outer edges.

I will re-true the stone and try this again. 

I will also try the honing wheel as-is again.  I read some of Jeff Farris' earlier threads.  He mentioned that sometimes the honing wheel has a bump which works itself out "after a few months."  If good results could still be had with a bump, maybe this won't prevent me from getting good results either.

Steve

Grepper,

I am sure the axle is not the problem.  I used a dial indicator to measure only 0.003" runout.

Steve

I checked everything in the chain.  First, I took better measurements of the honing wheel "oscillations."  They were a just shy of 3/32".

The plastic wheel that the leather is mounted to is not too bad, probably as good as can be expected for a molded plastic piece.  I did not measure the out of round of that piece, but I would guess under 0.010".

The axle is pretty good in my opinion.  Using a dial indicator, I measured 0.003".

It appears that the culprit is really the leather strip.  I tried shaving the wheel down, using the SVD-110 support and a straight scraper blade held perpendicular to the wheel, with the machine running.  This is difficult to achieve good results because the leather yields when it contacts sandpaper or a blade.  After almost 45 minutes of this, I still measure the out of round to be a strong 1/32".

I tried rotating the wheel in 120 degree increments - that really did not change the results.

It probably would not hurt to try honing with this wheel as-is.  But I have read that honing can be tricky, and this could be working against me from the get-go.  I will try honing when the compound gets delivered later this week.

My rubber drive tire seems to be degrading, and it has a bad divot from siting in one spot for a few years.  I might have to replace that soon.

I appreciate everyone's thoughtful comments.  I will report back after I try honing.

Steve

Thanks for your comments Grepper.

I also thought I had found the solution as you described in #4, but it was installed with the pins aligned.

Your ideas in #3 should help me get to the bottom of this.  I really hate to keep sanding the leather.  I will report back.

Thanks!

Grepper,

I measured the length of the trouble spot by holding a marker on the tool rest and moving it very slowly into the spinning wheel.  As soon as I could tell that contact was made and I saw the mark on the wheel, I stopped moving the marker.  I shut off the machine and observed the mark - it was about 5 inches long.  Low tech, but that was how I did it.

The increase in thickness is not sudden.  It seems that the thickness increases gradually to a maximum of about 1/8 inch.  The 1/8 inch can be observed by comparing the spinning wheel to the stationary usb or a work support.

I can take another shot at some more aggressive and targeted sanding if this is a normal procedure.

I would appreciate any additional comments.  Thanks.

Steve

I posted a few weeks ago that I am the new owner of a Tormek Supergrind 2000.  I got it cleaned up, got the truing jig and a new usb and a new horizontal support base, and a few other jigs.  I wish I remembered to get the honing compound also.  It will be here Tuesday.

The grinding stone was out of true by about 1/8".  It took a while to get it round.

I took a test run on the grinding stone with an old chisel and I am amazed at how fast I have a nice new bevel!

I could also see that the leather honing wheel was out of true - by about 1/8".  I assumed the high spot was at the seam, but it is not.  The trouble spot is about 5 inches along the circumference of the wheel.  I tried using a piece of sandpaper on a piece of wood (supported by the SVD-110 support) to true the wheel with the machine running.  I think it helped, but not much.

The axle that supports the honing wheel is not the culprit.  It is not machined perfectly, but it is not the cause of this issue.

My efforts to search for past threads did not turn up much as far as solutions.

Any ideas?  Do I need to order a new honing wheel?  This thing was not heavily used before I bought it.

Thanks.

Steve

Thanks Herman and Ken.  I appreciate the responses.  You both bring up some good ideas to consider.

I have the older straight edge jig right now.  I figure I will get my feet wet with that one and decide if I need to upgrade to the new version.

I will get the stone trued and may be back with more questions.

Steve