Sunday, January 13, 2008

Inshaves Revisited

I had a recent inquiry about the oxhead inshave that I used. The question was in regards to the handles which seemed to get in the users way. I don't think that the company has changed the angles of the handles, so my assumption is that a change in technique may be enough to correct the issue.
I have mentioned in previous posts that I prefer the flatter profile (and cheaper price) of the oxhead inshave. Inshaves fall into the catagory of "most misused tools". It presents itself with two symetrical handles that just scream to be pulled evenly towards the user. Combine this with the mistaken notion that one should cut "with" the grain and you have a recipe for hacking, chattering, digging and sweating your way to a seat.
The photo below (thanks to Jeff Lefkowitz for the hand modelling) shows the inshave held in the best cutting position. Note the arrow showing the direction the tool is travelling.

As you can see, one hand is leading the tool in a skew across the grain of the seat. By skewing the tool and working cross grain, the handles never pose a problem and the cut is clean and easy. When the tool starts creating tearout, simply switch to the other hand leading and you'll see clean shearing cuts again.
Using the inshave this way sounds simple, but don't underestimate the innate desire to pull both handle towards yourself, it is irresistable in those new to the technique.

Below is Jeff with his chair in the home stretch of assembly. Jeff came to me as an experienced chairmaker, so we spent most of the week talking fine points and comparing technique. Next, Jeff is going to take a two week course with Brian Boggs at Kelly Mehler's School in Berea. Best of luck Jeff.


Anonymous said...

Pete - The one thing that jumped right out at me is, if you skew cut in the direction of the arrow, how come the handles are not angled outward more?
when I skew my drawknife, it usually ends up with a handle pointing straight at me. It would seam that with the handles angled out more it would give the user more .... comfort to use it that way.
but what do I know - I only make post and rung chairs and have never picked up a inshave.
Great Blog - Scott Estepp

Peter Galbert said...

The handles could angle a bit more to make the skewing action feel more natural. As I cut with the inshave, I often switch back and forth between the left and right hand leading, once one gets used to the feeling, the control is easy. I have seen other inshaves with slightly more angled handles, but they all have a curve that I find too round. It's one more situation where the tool makers and tool users are on a different page!
Thanks for the response.

rocking R rustics said...

I have several regular draw knives, and was thinking of bending one into an inshave. Do you think it would work? I am not sure if the inshave has the same cutting angle as the draw knifes do.
Thanks Pete

Peter Galbert said...

Bending a drawknife is a bit complicated. It will require a forge and a good bit of blacksmithing expertise to create the proper shape and then to reharden and temper the blade. Given that many older blades are cast steel, this may add yet another wrench in the works. That said, it is doable and you can get the tool the way you want it to be. If you are interested in persuing it, I can go into the process deeper. Just let me know.

Anonymous said...

I get the skewed cut but would have assumed the other direction (coming from the gutter toward the chair center) for better support of the wood fibers. Where did I get turned around?

Mike H.

Peter Galbert said...

I think that the cut shown is heading into a transition area and that if he proceeded toward the back of the seat that he definitely should switch directions of skewing. Sometimes, because of the way the fibers run in a sawn plank, the transition areas can be in unexpected places! Thanks for the observation,