First Big Bowl

[dkerfoot]

Roughed out my first big bowl today. 12" x 5" Wow - that was an experience!

I use a ShopSmith as a lathe. It has a 16" swing, but is light weight for a lathe. It also has a wonderful mechanical variable speed, but unfortunately only goes down to 700 RPM.

I knew it would be fast for a 12" bowl, but dang! Those chips hurt while using the roughing gouge! Once I got to where I was using the bowl gouge they were fine, but it was a violent experience in the beginning.

There was also a fair bit of shaking until I had the blank balanced. I am glad I went the conservative route and purchased a pre-rounded blank.

All in all, it went pretty good. I have the bowl roughed out to about 1" thick for drying.

[Uncle Cracker]

Yup. The bigger the bowl, the bigger the fight in the beginning. Sometimes it helps to stop and adjust the tool rest more often than you want to, in order to keep the rest close to the work. This will put most of the force and roughness downward into the lathe bed, rather than bouncing you up and down on the handle. For outboard turnings, I have a friend who even has a floor-standing tool rest he uses for roughing, as the S-rest attached to the ways is not as stable. For similar reasons, long handles on your roughing tools will keep you farther from the violence. There is no need to be close to the work until you are needing finer detail and control.

[SteveR]

Wow is right, I feel your fear and pain LOL I am afraid of bending the driveshaft if that is even possible.

With any big, the SS grows legs and sprints across the shop. SS does offer a speed reducer that takes it down to 100 rpm, but a new one is a bit pricey...Used ones seem to be few and far between as they are popular.

To help with rounding, I will use the tailstock as well, but still is an adventure sometimes even after trips to and from the bandsaw. Also trying to figure out an easy takeoff/put on weight system to help ease things some.


Steve

[DonHo]

I have a question about "while using the roughing gouge". I've read and seen on several bowl turning dvd's that a roughing gouge should never be used in bowl turning. I don't claim to be an expert by any means but I've never used a roughing gouge for roughing a bowl blank, only a bowl gouge and some times a heavy scraper. I only bring this up because of safety concern and maybe to get the input of more experienced turners. The reason I've heard for not using roughing gouges is 1: that the grind is not suited for bowl turning and 2: that roughing gouges have smaller tangs that could break more easily with a major catch.
In any case, congrats on having roughed it out successfully.
DonHo

[Uncle Cracker]

Roughing gouge is for rounding the outside of the blank only. If you try to use it for hollowing out, it'll catch on the concave surfaces. Use a large bowl gouge or round-nose scraper for that.

[drumpriest]

UC, some people claim that because of the construction difference between a bowl gouge and a roughing gouge that you should use the bowl gouge for all of it. The tang is a big part of it, a bowl gouge has a much longer tang than a roughing gouge, and with a roughing gouge it is entirely possible that you could break out the steel from the wood if you are not careful.

[dkerfoot]

UC, some people claim that because of the construction difference between a bowl gouge and a roughing gouge that you should use the bowl gouge for all of it. The tang is a big part of it, a bowl gouge has a much longer tang than a roughing gouge, and with a roughing gouge it is entirely possible that you could break out the steel from the wood if you are not careful.

I have heard both opinions expressed - No roughing gouge at all vs. Only on the outboard.

I actually considered both points of view and decided the prudent course in this case was to get the thing balanced ASAP.

I would love a speed reducer and have been scouting for a used one. They are indeed few and far between. Anytime you order anything from ShopSmith you can get 20% off an additional regular priced item within 5 days. That brings the price down to a still substantial $225.

Internally I am weighing the two competing thoughts:
How many big bowls do I plan to make? (probably not enough to justify it)

Vs.

It looks like ShopSmith is probably on the verge of going out of business - you may never be able to get one if you wait!
(They don't charge your card until it is shipped so no fear of paying and not receiving. Also there are enough ShopSmiths out there to be able to get spare parts forever, so no worries about keeping the basic machine running - just the availability of specialty items like the speed reducer.)


Just to highlight my fear while roughing out this big bowl, last week I had my first (and hopefully last!) experience of having a small bowl come off the chuck at about 1200 RPM or so. It flew straight up into an overhead fluorescent light and resulted in a fairly spectacular shower of wood, dust and tiny shards of glass flying everywhere. There is nothing like imagining the same thing happening with an object of at least 400 times the mass to keep you on your toes!

It also made me even more appreciative of the very nice 3M full-face respirator I picked up at a local auction for $30 a couple weeks ago. Any Navy Vets would instantly recognize it as a non-military version of the MkV Gas Mask. I was pleasantly surprised to find it is considerably lighter and the rubber is softer. I surely never thought I'd be "sucking rubber" as part of a hobby!

http://www.drillspot.com/products/11...ace_Respirator


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[Uncle Cracker]

UC, some people claim that because of the construction difference between a bowl gouge and a roughing gouge that you should use the bowl gouge for all of it. The tang is a big part of it, a bowl gouge has a much longer tang than a roughing gouge, and with a roughing gouge it is entirely possible that you could break out the steel from the wood if you are not careful.

I can't argue with that logic, but my point was that only outside surfaces should even be considered for the roughing gouge. (Between you and me, I use one just for blank rounding, with nary a problem to date, but it's a very good one... And I am careful to keep the tool rest close to the work.)

[Uncle Cracker]

It flew straight up into an overhead fluorescent light and resulted in a fairly spectacular shower of wood, dust and tiny shards of glass flying everywhere.

Might think about guards for your fixtures, or at least clear plastic tubes for the, uh.. tubes. Always a good idea around spinning machinery.