bowl gouge at 55 degrees for bottom of bowls

[mick59wests]

Hi,

I decided to have one bowl gouge ground / sharpened at 55 degrees to get to the bottom of bowls. I used a 12mm P&N bowl gouge but have had terrible results. I seem to be catching it all of the time. It looks to me that there is not enough metal in the middle of the flute to really support this grinding angle (photo attached). What I am after is some considered opinion as to whether:
- this is just me and perhaps I should learn to use the tool better :)
- do I need to find a different tool to properly support this grind and if so, what have others successfully used?

All help greatly appreciated

thanks

Mick

[RETIRED]

Are you using a jig to sharpen? The wings look to be too long in the bevel.

[mick59wests]

Are you using a jig to sharpen? The wings look to be too long in the bevel.

- yes - I am using the Tormek woodturning jig on a Sheppach 'water cooled' grinder. All my other gouges are at 45 degrees (different setting of course) and seem to do the job (at least as best as I can tell).

You certainly may be right (not the first time after reading lots of your posts :)) - perhaps I have just been a slacko and the original grinding has not changed the shape of the entire gouge. I have added another photo - maybe I also need a better camera!

thanks

Mick

[Wood Nut]

I have been looking at grinding one of my bowl gouges in a similar fashion to more easily access the bottom, but the wings (as says) are way too long. They are a catch waiting to happen - I guess you have already figured that out. What about a more fingernail type grind. At least get the wings out of the way.

and others know a lot more about this than me, but I would not use it in its current form.

Cheers,
Paul

[Pat]

Try to grind it flat, like a Spindle Roughing Gouge, the nose and wings are flat as possible, until the tips of the wings, which are relieved. My bottom or transition bowl gouge is ground at 55°. The relief is about 5.5°247075247074247076

[mick59wests]

thanks all for the advice. It was not even one of the things I thought was wrong so am most grateful :2tsup: I'll try to work out how to do it on the Tormek jig and hopefully within a week will be able to give it a go on the next bowl I am doing.
cheers
Mick

[Pat]

Mick, I use the Multi Jig (http://www.tormek.com/en/jigs/index.php), as the Gouge Jig allows to much side bevel.

[RETIRED]

Pats shape is right.

As stated in another post, P&N can be a little hard to get right due to the flute shape (and being off centre).

To reduce the wing move the tool support in towards the wheel. Set your jig with the tool straight in to the wheel to get the nose at 55 degrees.

With that angle you nearly get a straight across grind as Pat has said.

The reason it is catching in its present form is that the wing hits before it has bevel support.

If you can turn the bowl by hand, or have someone else do it, have a look and see what happens. Makes understanding it a lot easier.

[artme]

I like P7N tools ( even though I don't own any :B ). I like them because of the quality of the steel ad the flute shape,
which is close to a Henry Taylor flute shape.

I ground a 15mm Robert Sorby to the shape Pat shows. Worked a treat!! Mind you that was simply an accidental thing!:B:B

[RETIRED]

Athur, most of P&N have a deep V, with very little steel under the flute. 247121247120 The flute finish varies from good to ploughed paddock but the steel is good.



HT superflutes have a parabolic flute.247123 A personal view of bowl gouges (http://www.peterchild.co.uk/info1/sflute.htm)




Their other bowl gouges are almost a "U".

247122

[issatree]

Hi All,
Not sure whether this is a help or hindrance.

I mainly use a 10mm. P&N Bowl Gouge when I do a Bowl, & that is not very often, I have to admit.
I sharpen my Gouge by Hand & have always done so, & it seems to work for me, & I can always get to the bottom.
After I have Sharpened my Gouge, I turn the Gouge, Flute down & hold on approx. 45%, & I like my Sharpening to be approx. 90%, with the Wings ground away a bit , & Straight, no curve like I have seen on some.
I use either a 60 or 120G White Wheels.
That Gouge cuts like a Demon, & with the Wings Straight, I can Skew with it if I wish.

[artme]

Thanks . I actually knew the differences in flute shape between the different brands.

I agree with you on the finish of the P&N flutes. A mate of mine spends time honing the flutes
of his P&Ns so that he gets a better finish straight off the tool.

The illustrations there, along with the explanations is enlightening, as is the statement that if
it works for you it is right.

I learned to do bowls with Henry Taylor and P&N tools. Perhaps that is why I prefer them. However
when I bought the Teknatool TL 1200 (second hand) it came with a 15mm Sorby gouge that was
badly shaped. I was trying to get some better shape to it at the club using a True Grind jig. An older
member came to give a hand. The shape was good but the angle, as he put it, was ""önly good for bowl bottoms!!""

Turned out he was right!:)

[rsser]

Mick, you got that result by grinding too long at the nose in relation to the sides. .

[rsser]

To rectify : get back on the wet grinder & grind back the wings til they have slightly convex tops well back from the nose seen side-on. This may take some time. Then blend the nose into those wing curves.

May take several goes but its only steel.


HTH.

[mick59wests]

To rectify : get back on the wet grinder & grind back the wings til they have slightly convex tops well back from the nose seen side-on. This may take some time. Then blend the nose into those wing curves.

May take several goes but its only steel.


HTH.

Ern,

I was going to give Pat's method a go (using the multi-jig) but will try this first

thanks :2tsup:

Mick

[rsser]

Use the full width of the wheel & clean it often with the stone. Also flatten it regularly with a diamond truing tool for best results.

[artme]

Best take note of what Ern says Mick!! He is a true fount of information and good tips when it comes to sharpening!!:):):)

[hughie]

St Carborundum, the sage of sharpeners :U

[Pat]

Mick, do as Ern "suggests", then once you have established the correct bevel, it's a 20 second job on the Torment.


Like all honing after you establish the edge . . . until you have a catch and take a chunk out of the blessed edge . . . The big Thommo needs some more love and attention, Damn it!

[mick59wests]

I reground the gouge - it did take some time. Hopefully I have removed enough of the wings to avoid the catches. If you don't think so, please let me know.
cheers
Mick

[Pat]

Mick, it still appears that the nose is slightly behind the wings.

[RETIRED]

Still too big. Like this is what you are aiming for.
247269 The red line.

[mick59wests]

Still too big. Like this is what you are aiming for.
247269 The red line.

I did another re-grind. I am not sure if it is quite as much off as above but I did try it out and did not get a catch. I did however have some difficulty getting a flowing smooth cut. I expect the small amount of steel remaining in the centre does not help but my skill level will also contribute!!! I will play around a bit more getting it properly sharp but will also consider making it flatter across the whole top (as per Pat's original suggestion - like a roughing gouge).
It has been interesting for me as it is the first time I have tried to change the shape of a tool. I have also very much appreciated all the help I have been given. Pictures of the new regrind attached.
thanks
Mick

[RETIRED]

Looking much better.

[Mobyturns]

Mick, 's comments are spot on.

Holding the gouge in your cutting position while some one else hand rotates the bowl slowly is a very good teaching aid as it lets you see where the cutting edge actually is but also where the wings or corners of the gouge are as well. Developing spatial awareness will come with practice - where all of the gouges parts are in relation to the bowl etc particularly the cutting area of the gouge - the part of the gouge that is actually doing the cutting which may not necessarily be the area of the tip or wing you think is doing the cutting. Sometimes putting graphite from a pencil lead on the wings of the gouge similar to using a marker pen to highlight the grinding area when sharpening is very handy when teaching by hand rotating a bowl as it marks both the bowl and gouge.

With the curved cutting edge on the flute wing it also makes it much more difficult, or should I really say a little more unpredictable, to do a pull or shear cut on the outside of a bowl.

You re getting the hang of it plus you have done a good job in maintaing a continuous flowing grind rather than a stepped or faceted grind.

Glenn Lucas - YouTube (http://www.youtube.com/user/GlennLucasWoodTurner?feature=watch)

[robo hippy]

For the bottom feeder type of gouges, specifically ground for going through the transition and across the bottom of the bowl, I have found a more open flute design, more C shape rather than V, is much easier to steer through those areas. The deeper flutes like you have are more difficult. The bottom feeders are similar to a spindle roughing gouge in grind, as in more square across the top of the flutes with little or even no sweep to the wings. When cutting you cut more with the nose part of the gouge, and not with the wings. It is important to roll the gouge on its side to prevent catches, though they will cut nicely with the flutes straight up and down as long as you do not cut up on the wing where the tool becomes unbalances and rolls into the cut. Big catch, and you know the rest of the story. These are not roughing tools, and made for fine finish cuts only. Another thing, I grind away at least half of the heel on the bevel. It fits much better on the inside of a concave surface. I have them with bevel angles from 60 to 75 degrees.

robo hippy

[chuck1]

here is my grind on a bowl gouge shown to me by a tradie when doing my apprenticeship. left hand side is left longer to use as a shear scrap across the bottom of the bowl, must remember to lay it on its side. so you dont have to change tools. all my grinding is free hand / free style then honed by hand. this wing I have left also helps redirect shavings.