Issues with Aligning Wood Turning Tools in the Multi Jig (SVS-50)

[RickKrung]

As part of sharpening things at my friend Bill's, last came sharpening some wood turning tools.  A bowl gouge, parting tool and a flat shew chisel.  Bowl gouge was first and went according to plan, using the Gouge Jig (SVD-186).  This is a sophisticated and well designed jig and the instructions were clear and informative. 

The Multi Jig seems so as well, but I ran into a couple of issues, both with the parting tool and the skew chisel.

First, the parting tool, used with the open seat of the jig.  Actually, the issue was with use of the assembled jig on the USB and not with setting the parting tool up in the jig (as is the issue with the skew chisel, below).  The parting tool mounts in the jig with its wide axis vertical, which presumably aligns it perpendicular with the horizontal bottom edge of the jig.  The jig is then held on the USB for grinding of the front face of the parting tool. 

The problem I ran into is that while the jig holds the parting tool perpendicular to the stone, there is nothing to keep the jig from rolling right or left, causing the long axis of the parting tool to no longer be vertical.  This results in a crowned front cutting edge of the parting tool.  Ever so slightly crowned, with concentrated effort to keep the tool vertical, but none-the-less, crowned.  It seems the jig is incomplete or improperly designed. 

I'm not a wood turner, so I have no idea if this is any kind of issue for parting operations, but it was frustrating as a sharpening exercise.  The machinist and tinkerer in me had me thinking of ways to modify or add to the jig in order to keep if from rolling so as to keep the parting tool vertical and the front face square. 

Is this a non-issue because it really doesn't matter and I'm just too detail oriented, or not? 

I'll go into my issue with the closed seat and the skew chisel in a separate post so as to help keep the responses focused. 

Rick

[RickKrung]

As part of sharpening things at my friend Bill's, last came sharpening some wood turning tools.  A bowl gouge, parting tool and a flat shew chisel.  Bowl gouge was first and went according to plan, using the Gouge Jig (SVD-186).  This is a sophisticated and well designed jig and the instructions were clear and informative. 

The Multi Jig seems so as well, but I ran into a couple of issues, both with the parting tool and the skew chisel.

First, the parting tool,...snip...

I'll go into my issue with the closed seat and the skew chisel in a separate post so as to help keep the responses focused. 

Rick

The problem I ran into with the skew chisel seemed to be an alignment issue, as does the one with the parting tool.  In the case of the skew chisel, the closed seat is used in the Multi Jig.  The skew chisel is mounted horizontally with the sides held in "V" shaped grooves, one fixed as part of the movable seat, the other at the end of the tightening screw/clamp.  The latter is a nearly complete "V" whereas the former has a small flat at the bottom of the "V", but that flat is about 1/8" wide. 

The skew chisel I was working with is curved over the wide sides terminating in very small flats on either edge, about 1/16" wide.  It is the difference between the width those flats and the flat bottom of the seat "V" where  I think (or thought) the issue is based.  The skew chisel can locate off-center in that flat "V". 

I worked hard to get it aligned squarely in the middle on that flat at the bottom of the "V".  See photo.


I thought that would be the end of it.

But, what happened is that grinding on the bevels of the cutting tip was uneven, as though the chisel was NOT lined up, in the way that I though would happen it was not well centered in that flat "V" bottom  (grinding occurred on the tip on one side and on the heel on the other side).  I changed the position of the chisel (putting it off-center) in that flat in an attempt to correct the observed grinding problem.  It didn't help (or at least not enough).   

I struggled through the sharpening and the result is not pretty.  I am at a loss to explain or correct the grinding mis-alignment. 

Talking about it after dinner, my friend Bill thought maybe the chisel itself was twisted, which even a little could cause the problem.  The chisel is not straight, there is a small bend close to the handle, but given its curved shaped sides, it is difficult to discern any twist. 

I'm baffled and open to any ideas that anyone may have.

Rick

[RichColvin]

Rick,

There are four things that come to mind from these two postings.

Firstly, my experience with the SVS-50 Multi-Jig was not good at first, but I've come to like it much more with time. 

The biggest frustration came from switching between the open and closed seats.  Took me more time than using the thing !  As a result, I found that it helped greatly by making it into two tools :  One dedicated to the open seat, and the other to the closed seat.  To do that, I purchased the needed parts from Advanced Machinery.  If I remember correctly, I only needed the housing (p/n 2200) and a locking screw (p/n 7090).


Secondly, if the housing of the jig is not held squarely against the USB, it can cause problems. 


Thirdly, as it regards the parting tool, I found the same issues as you noted.  It is even more pronounced with the slim parting tool than with the diamond tool, but less noticeable in the end. 

One thing I found was that, when I was sharpening the tool, shifting the tool side to side caused most of the issues, as the tool didn't slide on the USB easily.  It seemed to catch a bit on the USB.  So, I keep it in one place and grind away.  Once the shape is there, this really isn't a problem as the resharpening doesn't take long and the groove in the wheel is unnoticeable.


Finally, as it regards the skew, I can't be sure, but it seems in your picture that the seat is in the jig backwards, and isn't skewed.  As noted on the 1st picture for the jig on the Tormek site (https://www.tormek.com/usa/en/grinding-jigs/svs-50-multi-jig/), the closed seat projects beyond the housing, and this rides on the USB.

Another factor which can cause this is if the grindstone's surface is not parallel to the USB.

I have a skew with rounded sides, and greatly like it over the flat sided ones I have.  I doubt the alignment in the jig matters greatly per se, but it is important that it be repeatable.  So, however it fits in the first time is how it should be sharpened.  This way it is resharpened again the same way.  (By the way, I doubt the skew is twisted.)

As for the sides being equal, they should be similar, but perfectly equal is not critical.  It is a tool used by hand anyway.


There are some good videos about sharpening using the SVS-50 on YouTube :
* Jeff Farris' video :  https://www.youtube.com/watch?v=PBF2NJCcgfY
* Tormek's video :  https://www.youtube.com/watch?v=lO0aOUIvPf4

Though neither does a great job showing how to sharpen the parting tool.


Also, for both of the tools, I ground a micro bevel on the SJ stone. 

Good luck,
Rich

[RickKrung]

Thanks, Rich,

On your first and second points, I can see how making them two dedicated jigs helps.  It is unlikely I will get to that point very soon, as I am not a wood turner and do not have a wood lathe.  I have a set of wood turning tools, but have never used them.  For wood turning, I have done what little I have done using my metal lathes.  Holding the jig firmly against the USB to keep it perpendicular was not much of a problem.  As noted, it was the rolling that was the issue. 

Third point, parting tool.  Yes, I agree that moving the jig/tool assembly is where the rolling was most troublesome.  I do not care much for the notion of keeping the tool in one spot on the stone, but I take your point as to the benefit.  I am more inclined to modify the jig housing to add a guide tab that (in concept) would help keep it horizontal to avoid the rolling. 

Finally, the skew.  With regard to jig setup, I had taken the skew out already, so could not check that it was installed at an angle correctly.  I did reassemble it to do that check.  I believe it was set properly, as I recall setting it at 20º.  There are marks on the closed seat, from sliding on the USB, indicating usage in that position as well. 

I believe the photo does not show enough of the housing to get an adequate sense of the angled position.  The view is face on, with the skew laying flat on a horizontal surface.  The jig housing is only partially visible and when reassembled and held in the same position, the top, angled, outer edge of the housing is very close to parallel with the side of the closed seat, which is what gives the impression of it not being angled in the photo. 

Sharpening the skew was very late in all the sharpening, so the stone may have been very slightly not parallel with the USB by then, but when I retrued it, it seems to me it was not enough so to make the kind of difference I was experiencing. 

I get it and agree that alignment may not matter that much, just as long as the working leading edge is sharpened.  Afterall, as you say, it is a hand tool. 

Functionally, the skew received a microbevel from the SJ wheel, simply because it was so difficult to get it even.  I can see the value doing it intentionally, as there is little value in polishing a wide surface that has no function in use of the tool. 

Thanks again for your comments.  It was my first experience with wood turning tools.  I am glad for it, but am not sure how much more there may be in my future.  I do like learning about it all, though. 

If I do any mods to the housing in regard to use of the open seat and the parting tool, I will post about it. 

Rick