Reshaping a bowl gouge with the Varigrind

[Tim Solley]

Hi all,

I'm still brand new to turning (read four pens and a couple small bowls). I bought a Oneway Varigrind for sharpening my bowl gouge after I quickly realized that I can't do it very well freehand. I also built a Wolverine clone sharpening jig.

The bowl gouge is a Sorby 3/8". The grind that it came with is not the same on the sides as on the front. With the Varigrind, it seems that the grind angle will be the same all the way around.

So my question is this: is it okay to just reshape the sides of the gouge until everything matches up all the way around? I could just grind it on a courser wheel and then finish up on the finer wheel.

Thanks for any input you all could provide. Your expert advice is always appreciated.

Tim

[Vaughn McMillan]

Tim, I don't know if you've seen these, but Oneway has some handy videos on their site, including one that shows what I believe is the answer to your question:

http://www.oneway.on.ca/multi-media/wolverine_videos.htm

I know these videos helped me figure out how to use my Wolverine clone from PSI.

- Vaughn

[Andy Hoyt]

Tim - For me, the success of the Varigrind has centered around setting the jig and the Wolverine up with the sides of the gouge against the wheel - not the tip.

Sharpen away on both sides. Then just kiss the tip to the wheel.

If you grind the tip with the same force (which shouldn't be all that much anyway) as the sides you'll continually get things cattywampus.

Light pressure and grind away, including the tip. Having a consistent bevel all the way around the gouge is really handy when you're making those fussy little finishing cuts.

And Vaughn's right - the Oneway videos do help.

[Jim Becker]

Getting the right setting to "match" an existing grind (or create a new one) will take a little trial and error. You need to insert the tool into the Vari-Grind the exact same distance every time...jig up for that. (I use the Ellsworth grind and the distances are very specific) About 2" projection is normal for a 1/2" gouge...I don't know what it is for a 3/8" gouge as I don't use or own one. It can be a hole in your table surface or a piece of wood fastened to the top that is 2" back from the edge. Whatever works for you.

Then, with the grinder turned OFF and the gouge in the Vari-Grind, check both the tip and the sides to see how well the bevel matches the wheel position. Starting with a fairly "vertical" setting of the jig and adjust the pivot point until the tip bevel mates with the wheel "about right". Then rotate the tool, keeping the pivot of the Vari-Grind in the vee-arm at the "right place". Check to see how the side bevel mates with the wheel. Make a small adjustment to the angle of the Vari-Grind and check again. Repeat until you have the bevel at the tip and the bevel on the side "about right".

Do a test grind with the power on and a very light touch, being sure to keep the Vari-grind engaged in the pivot point...use TWO hands; one on the tool and one on the jig and do one side at a time. Don't spend much time on the tip...quickly move on so you don't over grind. You'll have to switch hand positions for each side... ;) If you are happy with the grind, SCRIBE the Vari-Grind so you can set the jig the same way in the future in case you have to change it for a different tool. (Spindle gouges require a very different, flatter setting for a fingernail grind) If not, make minor adjustments and repeat the live test until you are. Light touch is essential with any grinding.

Now, make yourself a little job aid to insure that the pivot point (the vee-arm) is EXACTLY the same distance from the wheel surface every time. (You can't just measure and mark the arm as the wheel gets smaller over time) I made a little doo-dad out of scrap 1/4" plywood for this purpose. (I use the Ellsworth grind and the distances are very specific) Just a piece of wood that contacts the pivot point "level" and contacts the wheel at the point it is closest to "you" is all you need. Mine is small and square...quick and dirty.

Now you have the setting for "your" grind on the jig and the necessary setup aids to insure a consistent job each time.

[Tim Solley]

Great, thanks for the replies. This confirms what I was thinking. I just wanted to make sure I wasn't missing something before I went off and took the factory grind off a $80 gouge.

One other quick question: I've noticed that the tip of my tools can burn when grinding, even when doing a very quick, light regrind. Is there something I can do to prevent this? Dip in water periodically perhaps? Or is this even such a bad thing? I am doing my grinding on a new aluminum oxide wheel (the white one).

Thanks again.

Tim

[Ned Bulken]

Tim, I don't recall which mag had it, but if you can lay hands on a heat sink out of a scrapped computer, it can soak up the heat as well, they showed one mounted to a bench next to a grinder. (probably Wood mag come to think of it)

[Ken Fitzgerald]

Tim........do you mean turn "blue" when you say burn? First, I've been told that that isn't too important with high speed steel. I'm a little leary so what I found is slow down and use extremely light "cuts" on the grinder. Even put the thing down.....wait a few minutes and go back to it. I think what is happening, to me anyway, there is a lot of residual heat building up and even a light pass pushes it over the edge. I've also been told that cooling HSS in water is a NoNO as it could change the characteristic of the metal making it brittle.