# new toy: articulated-arm hollowing jig



## duncsuss (Jul 25, 2016)

A friend who enjoys machining and woodworking offered to make an articulated-arm hollowing jig for me. It has a MT2 that fits into the tailstock (tapped for a drawbar to make sure it stays in there), a couple of arms, and a head that's drilled through to take a toolbar. He drilled through some 3/4" bolts to use as collets for the bars, the hex head keeps things oriented.

I could ramble on, but a picture might make it clearer than any amount of description:





I bought the Sorby swan-necked hollowing tool (it's the "midi" size). He made the 1/2" straight bar that's installed in the head, it has a swiveling holder that locks down on a 1/8" square cutter and the 5/8" bar (with the blue tape) -- this has a 1/4" hole drilled at 45 degrees, the cutter is epoxied in place.

Before tightening the drawbar, I used the lathe toolrest to level up the aluminium arm (with the elbow the opposite side of the lathe bed).




The post with the handle on the head is drilled and tapped to take the laser pointer holder I original used clamped onto an EasyWoodTools hollower.

I drilled out with a 1" Forstner bit, shaped the outside, then started hollowing with the swan-necked tool.





After getting under the rim with that, I switched to the straight 5/8" bar and began working my way down the form. I'm a bit further than 2" into it now, another 1.5" to go.








I really like this way of hollowing. Not having to maintain a strong grip on the tool handle and be constantly aware of exactly how level the tool is makes it so much easier -- I can relax and pay better attention to where the cutter tip is in relation to the sidewalls of the form.

Reactions: Way Cool 7


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## Schroedc (Jul 25, 2016)

Yes, I've been finding a captive hollowing system makes a world of difference myself. Have you used the Carter or Jameson hollowing rigs before? I'd be interested to see how the articulated one compares. Nice looking vase you've got going there!

Reactions: Thank You! 1


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## barry richardson (Jul 25, 2016)

looks cool! Time to get some bigger blanks

Reactions: Funny 1


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## duncsuss (Jul 25, 2016)

Schroedc said:


> Yes, I've been finding a captive hollowing system makes a world of difference myself. Have you used the Carter or Jameson hollowing rigs before? I'd be interested to see how the articulated one compares. Nice looking vase you've got going there!



This is the first hollowing jig I've used, so I've nothing to compare it to.

One of the club members made a jig based on the Trent Bosch design -- articulated arm, but with a post to hold the rear end (instead of using the tailstock) and the head was designed with a clamp to fit onto the ferrule of your existing hollowing tool. He demonstrated it a couple of months back -- and the WiFi videocam he attached in place of the laser pointer, letting him "see" where the tool head is on his Android tablet.


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## duncsuss (Jul 25, 2016)

barry richardson said:


> looks cool! Time to get some bigger blanks


LOL! I've got several on the shelf, but I'm going to work up slowly -- which is quite unlike me


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## gman2431 (Jul 25, 2016)

Awesome! Have some fun with that!

Reactions: Thank You! 1


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## DKMD (Jul 25, 2016)

That's cool! I'm still using the laser on mine, but those tiny cameras look really interesting for thin walked forms.

Reactions: Agree 1


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## duncsuss (Jul 25, 2016)

DKMD said:


> That's cool! I'm still using the laser on mine, but those tiny cameras look really interesting for thin walked forms.


Ralph Rumery gave the demonstration and wrote up some excellent slides to go along with the presentation -- his is the April-16 demo, videos and slides on THIS PAGE (I think he gives details of the camera and tablet he's using)

Ralph also thanked Trent Bosch multiple times for giving him permission to copy both his jig design and the idea for the camera (which Trent says was inspired by his daughter saying "you need an Xray camera in place of that laser pointer" )

Reactions: Like 1


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## Spinartist (Jul 26, 2016)

DKMD said:


> That's cool! I'm still using the laser on mine, but those tiny cameras look really interesting for thin walled forms.




I use a spy camera in place of the laser. Even a brand new woodturner can make a hollow form with this. You WILL NEVER USE A LASER AGAIN!!! It's a game changer like Trent says.

I have just a computer monitor, no computer, hooked up to the spy cam. A small TV works too.
Draw your tool on the screen with a dry erase marker then get hollowing!!

Reactions: Like 1


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## duncsuss (Jul 26, 2016)

Spinartist said:


> I use a spy camera in place of the laser.



Link please

Reactions: Agree 1


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## Spinartist (Jul 26, 2016)

Link below to South Florida Woodturner Guild newsletter with demo I did. 

http://www.wood.sfwtg.com/SFWTG-Newsletters/2015-08_newsletter.pdf

Page 2 has links to parts. Page 4 shows usage & set up ( they forgot to show power hookup for video converter) . Can be used on almost any hollowing system where a laser is used. There is a 16' cable available instead of the 50' but you need to order adapters for it. I use an old computer monitor got at garage sale fer $5.

If you use a TV you don't need the video converter.

Reactions: Like 1 | Thank You! 1


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## Spinartist (Jul 26, 2016)

Or go to www.sfwtg.com & click through to Aug. 2015 newsletter.

Reactions: Thank You! 1


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## duncsuss (Jul 26, 2016)

Spinartist said:


> Link below to South Florida Woodturner Guild newsletter with demo I did.
> 
> http://www.wood.sfwtg.com/SFWTG-Newsletters/2015-08_newsletter.pdf
> 
> ...



Thanks, Lee -- I've got a feeling this might be how I use up the Amazon gift card balance I've been saving for something special  

I've got a spare LED PC monitor, it probably isn't a clever idea to use a CRT unit when there could be debris in the air


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## Spinartist (Jul 26, 2016)

I used copper pipe fittings in the newsletter. But the camera (5/8" diameter) fits perfect in a 1/2" cpvc fitting - not the white pvc, the slightly yellow ones.

Reactions: Useful 1


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## Spinartist (Jul 26, 2016)

Oh.. An after market back up camera for a car can work to!!

Reactions: Funny 1


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## duncsuss (Jul 30, 2016)

Today I finished the first hollowform that used the jig. It has a very simple finish -- after sanding to 400 grit, I buffed with Tripoli compound, then with white diamond compound, then with carnauba wax. It measures 3" diameter and stands just under 4" tall. (I'll try a larger one next time.)

Even hollowing down at the bottom of the form, I was able to relax and didn't worry about maintaining control of the hollowing tool. No white knuckles, no clenched jaw ...

Reactions: Like 3 | Way Cool 1


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## Spinartist (Jul 31, 2016)

Nice turning! What's the wood?


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## duncsuss (Jul 31, 2016)

Spinartist said:


> Nice turning! What's the wood?


Thanks -- it's a piece of the maple tree that used to stand a few houses down the street. The town installed a sidewalk 4 or 5 years ago and quite a lot of trees that were within 3 feet of the roadway were felled. I'm still working my way through what I saved from the chipper


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