Thread: Thompson 5/8 U gouge - first impressions

Ern is partly right.

I've taken shear to mean anything done by an edge with no bevel support at an acute angle to the direction of the travel of the wood.

Again the bevel rubbing/not bevel rubbing. By definition, cut = bevel rubbing. Scrape = no bevel rubbing. So, if my scraper is flat on the tool rest, then it is a shear scrape? No. It is pure scraping.

If my scraper is at a 45 degree angle, it is a shear scrape?Yes provided that the included angle is less than 90 degrees to the wood.

If my spindle gouge is on its side, no bevel rub, pull cut it is a shear scrape? Yes provided that the included angle is less than 90 degrees to the wood. Similar to what Michael Mouse does.

If my Bowl gouge handle is dropped and flutes rolled over, and no bevel rub it is a shear scrape? Yes provided that the included angle is less than 90 degrees to the wood.

My rock hard Irish head just can't seem to get around this as there are 3 different cuts here to me.

The type of tool and the way it is presented to the work denotes a shear scrape.

I've taken shear to mean anything done by an edge with no bevel support at an acute angle to the direction of the travel of the wood.

So, 'shear' cuts with bevel rubbing are something else...
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Originally Posted by robo hippy

I do grind off the back of the bevel on my gouges. Main effect is that when turning the inside of a bowl, the bevel will rub closer to the cutting edge. Not a problem on the outside (convex shape) of the bowl, but more of a problem on the inside (concave shape). Stewart Batty explained that if you are rubbing the heel of the bevel on the inside of a bowl, it does 2 things. One, it can bruise the wood because it is a rather sharp edge. Two, it actually pushes the gouge into the cut, which is part of why you can some times see concentric rings on the inside of the bowl. Ever notice how much easier it is to turn the outside of the bowl than it is to turn the inside? It isn't all due to just being able to see the outside shape/form better than you can see the inside. I don't grind a second bevel, but round it over by rolling and raising and lowering the handle so it is rounded.

Rounding the sharp heel to minimise bruising is understood.

On the second point, I've always found that sideways thrust as you lean into the inside cut is one of the nice things that happens when hollowing out a bowl and, if necessary, a finishing cut will tidy up any irregularities...

Anyway, I did experiment at one stage with easing back the heel on some of my bowl gouges and found that it felt more comfortable with the primary bevel ground back to an even higher angle than my normal 60deg. I guess this is what I had in mind in connecting a higher grind angle on a gouge with a 'secondary' bevel.
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Some more comments about the Thompson U 5/8 gouge after roughing a good size lump of green Elm (starting size about 40cm) ....

Of course lumps of timber vary but I'm inclined to think now that Doug is right, that it's harder work roughing the outside with this gouge than with a 5/8 V. But anyone at home with a P&N Supagouge will find this works similarly.

As for hollowing, yes, the wide even arc of the cutting edge means you don't quite have to be on the ball with presentation to the same extent as the V gouge. As you go deeper and wider you can readily roll the tool increasingly using the left wing at the rim and rotating through to the right wing as you come to centre.

There was more tool chatter than I'd expect as the overhang increased and it was easily dealt with by swinging the rest in closer. Normally I'd lower the tool handle and 'climb' the wall more but the VL175 banjo top is too high to allow this.

So is there a compelling reason to opt for a U gouge over a V gouge if you can only have a quiver of one? I don't think so.

But one snowflake does not a winter make.
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