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A Different Lathe Chucking Technique

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Forum topic by poopiekat posted 1192 days ago 1646 views 0 times favorited 10 replies Add to Favorites Watch
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poopiekat

3552 posts in 2330 days


1192 days ago

Topic tags/keywords: lathe mounting turning chuck segmented jaws tip

Being fairly new to turning, I sometimes discover that my set-up strategies fail me. I have a few projects put aside because of errors, because I lacked the proper chuck to mount them. Though my 3-jaw scroll chuck is quite versatile, it cannot be used in every woodturning situation. So I bought a “Super Nova 2” chuck, and as soon as I put it on the lathe, I knew my options increased ten-fold. Rather than write a review of this chuck, I will resist the tendency of some LJs who run to the keyboard and hammer out a review of a tool they’re hardly familiar with. I have no other experience with other brands of woodturning lathe chucks with which to make a coherent comparison with, and indeed there were other makes and models of chucks on the shelf which may surpass the Nova series. Now, on to my newly discovered procedure for mounting the project into the chuck: With the use of three successive hole saws, I was able to create a recessed circular ring in the bottom of the project, by which the jaws can expand and grip the project from the bottom, as shown here: Photobucket and then, using the same pilot hole, I bored two successively-sized holes, all 3/8” deep. Just a bit of cleanup with a chisel to break out the remaining waste, and voila! Photobucket The recess is ready to accept the Nova Chuck jaws: Photobucket The use of hole saws give one other handy advantage to turners, and that is the ability to quickly make sacrificial bosses that can be mounted to your project and then gripped by the jaws of your chuck. Photobucket Once hollowed out, this lid can be turned around and chucked in my scroll chuck, and the sacrificial boss can be tooled away.
By this method I was able to salvage a little project that hit a brick wall due to mounting problems.

-- Einstein: "The intuitive mind is a sacred gift, and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift." I'm Poopiekat!!


10 replies so far

View hairy's profile

hairy

1988 posts in 2128 days


#1 posted 1192 days ago

That’s a good one. I’m a fan of a glue block, you won’t lose any of your project with it.

-- what a long, strange trip it's been...

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bubinga

861 posts in 1263 days


#2 posted 1192 days ago

I would do that with the router, with a circle jig, that many routers come with as standard equipment

-- E J ------- Always Keep a Firm Grip on Your Tool

View lew's profile

lew

9937 posts in 2351 days


#3 posted 1192 days ago

Cool idea, Poopie!! Thanks!

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Arthouse's profile

Arthouse

226 posts in 1246 days


#4 posted 1192 days ago

Poopie , I understand your bliss with the new chuck. Since you seem to be early in your development of the lathe, I ll tell you my experience. The secret is not the holding of the wood but the angle of your bowl gouge. If it ground right it does not have the stress put on the turning piece or the chuck. I had a variety of gouges, scrapers until and an old wise turner showed me the angle cut on my1/2’’ bowl gouge and now I only use the bowl gouge for everything even scraping. Good luck

-- "The hand is the cutting edge of the mind but the wind and sun are the healing factors of the heart

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poopiekat

3552 posts in 2330 days


#5 posted 1192 days ago

Hairy, ..Right you are!! I’ve always kept a bunch of squares, mostly made of particle board, but…they’re SQUARE!! And don’t forget, instead of a male glue block, you can use a block with a hole in the middle by which to fasten your chuck jaws into! Cutting them out with hole saws guarantees roundness, and makes roughing-in a whole lot easier! bubinga: The problem with a router jig is that you’ve got no way to assure yourself of getting the routed hole spot-on to the axis. With a hole saw, you’ve got the pilot bit inside indexing your center axis, which gets really important when stacking contrasting segments. However, with a rough block you can establish your axis by wherever you decide to put your router jig. The other advantage to the ring is that you can expand your chuck to grip the outside of the round groove, or grip the inside. I’ve still got to figure out which hole saw size has the optimum diameter to achieve full contact with the radius of the jaws. More to come!

-- Einstein: "The intuitive mind is a sacred gift, and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift." I'm Poopiekat!!

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poopiekat

3552 posts in 2330 days


#6 posted 1192 days ago

Arthouse: Yeah, I do find the hollowing out to be the most tedious part of hollow-form turning!I’m having best luck with carbide metalworking tools, brazed to toolholders, and clamped to a vise-grip for a handle. Then follow up with a conventional scraper. I want to buy some round carbide inserts and bolt them to a metal shaft. I am aware of custom grinds on gouges, but have not yet found resources to learn this skill.

-- Einstein: "The intuitive mind is a sacred gift, and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift." I'm Poopiekat!!

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LesB

1058 posts in 2038 days


#7 posted 1192 days ago

I would suggest using a router with a 8 degree dove tail bit and template guide. Make a template out of 3/4 plywood with the size circle you need cut out (with a hole saw) that can be clamped to the block you want to turn. With that set up you can cut either a spigot or a recess in the blank for the chuck to mount on or in. I prefer to use a 3/16” to 1/4” recess which I usually put in the top of a blank (say for a bowl). Then I turn the bottom and in the process create a new recess in the bottom which I will leave in the finished product. I usually decorate that recess from the center out with concentric beading leaving just enough room at the outside for the chuck jaws to fit into. When the bottom is completely finished, including sanding, I turn the piece over using the new recess to mount the piece and then turn the other side.
If you are roughing an out of balance block I suggest also using the tail stock and a live center for safety until it can be turned to a concentric or balanced shape.
I also use that recessed space where the chuck jaws fit into the bottom to sign, date, and identify the wood. I use one of those inexpensive vibrating ingravers for that.
One advantage of this method is that even years down the road I can remount the piece and refinish it on the lathe. I have had to do this with several salad bowl that received a lot of use and needed refinishing.
I find this a lot less work than the glue block method which I revert to only when necessary.

-- Les B, Oregon

View bubinga's profile

bubinga

861 posts in 1263 days


#8 posted 1192 days ago

The problem with a router jig is that you’ve got no way to assure yourself of getting the routed hole spot-on to the axis.
Maybe I am missing something here, but wouldn’t the pin , on a router circle jig, (that would be put dead center on your stock), be the same thing as the Pilot bit, on the hole saw ?
Is there some reason why you want to actually drill a hole in the center ?

-- E J ------- Always Keep a Firm Grip on Your Tool

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LesB

1058 posts in 2038 days


#9 posted 1191 days ago

Bubinga,
If you use a template with the appropriate size circle cut in it and a template guide on your router you can get as accurate you need. I often use a compass to draw a circle on the blank slightly smaller than the template to guide the placement of the template. The template can be used over and over and you can make several different size circles in the same template board. I probably should have gone into more detail but I figured everyone would figure out their own variation on this idea. My templates are usually made of 3/4 material about 6 inches wide and a two of feet long. Then I place the blank on the corner of a work bench with the template on top and diagonal on the corner of the bench. That way I can clamp each end on the two sides of the work bench and they are not in the way of the routing process. I often prepare several blanks at once; even if I’m not going to use them right away.
I normally use a recessed cup instead of a spigot for mounting in a chuck but because the first side i turn is usually on the bottom (of a bowl) you could make a spigot on the bottom that can be removed later.
I know some people think a recess mounting method is weaker than a spigot but I have not has a problem with the hundreds of bowls I have turned.

-- Les B, Oregon

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bubinga

861 posts in 1263 days


#10 posted 1191 days ago

I was not trying to be difficult in any way, and I am by no means an expert Turner
as a matter of fact I have never turned a bowl, the closest thing to a bowl was a goblet

-- E J ------- Always Keep a Firm Grip on Your Tool

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