Technique - How to get a flat (inside) bottom?

[Tom Jones III]

No this is not a "Buns of Steel" question so keep your thongs covered. I am consistently challenged by trying to get the inside bottom of a bowl flat and smooth. My current project is a bowl 8" in diameter; it is deep enough that I cannot use a bowl gouge to effectively flatten the bottom. I have been using a 3/4" round scraper. This scraper works great to get the wall and the bottom/wall transition. However I'm having a hard time using this scraper to make a flat surface. Is this a technique problem? Is there a better tool for this job?

[Andy Hoyt]

Tom - I've always held to the notion that pots have flat bottoms and bowls have round bottoms - on the outside and inside.

Assuming that you're sticking your toolrest in as deep as possible, my guess is that you've got a toolrest shortcoming (pun intended).

With a long curved rest and an Irish grind on a bowl gouge there's not much you can't reach.

[Lee DeRaud]

What Andy said.

Or you can do what I do: cheat and use a square scraper. :p

[Bernie Weishapl]

Or as I do and use a Sorby multi-tip scraper.

[Doug Jones]

I had this problem also and Kevin Gerstenecker helped me out with it one day while visiting. What he showed me was to get the tool rest inside the bowl as deep and safely as possible. Start the bowl gouge going into the bowl as normal but as you are moving towards the center of the bowl rotate the gouge so the flute is rotating away from you. Basically you are moving the gouge in two different directions, in and rotate.
Not sure if this helps, I had to be shown (hands on) for me to get it. But since then all my bowl have a nice flat contoured bottom. No more ridges or grooves or anything of the like. This technique also helped with the transition from the wall to the bottom.
Hope this helped, if not, well I tried.

[Reed Gray]

I agree with Andy in that a bowl should have a curved bottom. Usually, the bottom is flatter than the sides, but never flat, it just doesn't feel right. Dead flat is very hard to do, and when cutting the bottom of a bowl, if you are going parallel to the grain, there is more chance of tearout. I have several WMD's that I use on the bottom. On flatter and smaller bowls, I can do it all with a swept back grind gouge. On larger deeper bowls, I have a deep bowl gouge ground to about 80 degrees, very similar in shape to a roughing gouge, but with the edges slightly ground back. I also have a couple of 1/4 round gouges that work well using a shear cut, with the point down.
robo hippy

[Tom Jones III]

My tool rest is straight and long, we'll leave it at that. A curved rest would definitely make things easier but won't I always have a problem getting the bevel to rub without hitting the rim of the bowl with the handle?

I've already got the Sorby multi tip so maybe that would be a no cost solution.

From Reed's post it sounds like a bowl gouge ground very steep would keep the bevel rubbing without hitting the rim of the bowl.

[Andy Hoyt]

Maybe this will help. Start at the rim with the flute pointing towards the center. Move the gouge in arc indicated by the dots and rotate the flute so it's always pointing in the direction of the cut.

44230

With variations on the Irish Grind as Reed points out your tool handle won't be an issue at the rim.

[Mike Vickery]

I agree with the square scraper. I you have a hollowing rig that takes a teardrop style scraper a cheap way to do it is get a hss tool bit ( i think they call it a cutoff bit) I get then from harbor freight it comes in a pack of 5 different bits for something like $2.50. I cut the cuttoff bit into thirds using a dremel with a cut off wheel and you can then grind one as a square scraper and pinch it betwean your boring bar and the washer to flatten the bottom. I also made a custom ground one to cut the dovetail in the bottom of bowls recesses to match my chucks jaws ( I expansion chuck instead of compression chuck my bowls). Not the most elegant way but cheap and effective.

[Rich Stewart]

What's wrong with using a scraper? I have always followed the notion that the inside of a turning should follow the outside, be it round, square, or otherwise. I use a square end scraper for flat bottoms and a round end scraper for round bottoms.

[Jim Becker]

If you are going for flat...the scraper is likely going to do a better job than a gouge for finishing things off. For something round, a side-grind gouge allows you to make the necessary sweeping cuts without having "positioning" issues that happen with a "regular" bowl gouge.

[Tom Jones III]

For those of you recommending a scraper, what size and shape are you using? It would seem that a very wide and flat scraper with the sides curved back just slightly would be best.

Currently the closest I have is about 3/4" wide and round nosed so using it to sweep the bottom means a single pin-point contact. This is what I used last night with the tool rest perpendicular to the ways just taking light passes so that it only contacts the high points.

[Lee DeRaud]

For those of you recommending a scraper, what size and shape are you using? It would seem that a very wide and flat scraper with the sides curved back just slightly would be best. My only square scraper is about 3/8" wide at the straight part of the edge: I made it for working on small boxes, but it works just as well for bowl bottoms and cleaning up convex curves on the outside. Seems like if it had a lot more edge in contact with the wood, it would also be a lot easier to catch a corner.

Then again, what do I know...I'm learning all of this on-the-fly. :p