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Hollowing Tool #1: Jakosh Hybrid Hollowing System

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Blog entry by Jim Jakosh posted 12-10-2018 03:15 AM 1395 reads 1 time favorited 18 comments Add to Favorites Watch
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This is a project, but it is not made of wood…....... it is made FOR wood.
Our past guild president,Jeff, and I were talking about the need for a better hollowing system over the Jamieson loop arm system that we both have. That system works but it is a bulky on the back end with the big loop and double bar set up.
Jeff brought over a Monster brand hollower that he is trying out and I found many different systems on You Tube including the Elbo system which was the first articulated arm system. They looked good so I thought I’d try to make one and see if I like it better than what I have. I finished it tonight.

It is an articulated system but it does not connect to the tailstock quill like the Elbo or to a separate stand you have to bolt down like the Monster. It drops into the banjo..I have 2 banjos on my lathe.

I must say it works super and floats in and around with all the bearings I put in it. I roughed out a project to try it out on and it did a fine job. I mounted a magnet on the back of the arm and installed the 1/8” Allen wrench needed to turn all the set screws on it. It is always handy and stays put with the magnet. I put a stop collar on the mounting post in the banjo so you can just drop it into the banjo and it is right on center all the time. I took the 7/8” bar and 3/4” laser bar laser from my Jamieson system and mounted them on this one

Here are some of shots of the final product:


These are all the parts that go into it


The post and the collar were raw steel so I blued them with gun bluing

These are the 6 thrust bearings that I used. All the counterbore depths were set so the arms have .010” clearance when tightened to keep dust out and not rub the paint.

I painted all the parts with black hammered finish paint. The two straps are 3/8” aluminum, the solid bar is 1 1/4” aluminum tube with steel inserts in the ends and the boring bar holder is 1 1/4” solid steel.


The laser is a cheap laser from Target and the switch does not last on them so I wired a 2 AA battery box with a switch on it and it works great and the 2 batteries last a whole lot longer than the one AAA

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!



18 comments so far

View Jerry's profile

Jerry

2952 posts in 1919 days


#1 posted 12-10-2018 03:25 AM

I feel like a dog in a roomful of humans. I hear the noises, but I don’t know what it means. Maybe somebody will give me a treat if I’m quiet… Seriously, this all sounds very very impressive, but I am not on your level when it comes to wood turning, so please accept my compliments in the spirit with which they were intended. I know it must be good because I have faith in you!

-- There are good ships and there are wood ships, the ships that sail the sea, but the best ships are friendships and may they always be. http://www.geraldlhunsucker.com/

View Joe Lyddon's profile

Joe Lyddon

10439 posts in 4323 days


#2 posted 12-10-2018 06:01 AM



I feel like a dog in a roomful of humans. I hear the noises, but I don t know what it means. Maybe somebody will give me a treat if I m quiet… Seriously, this all sounds very very impressive, but I am not on your level when it comes to wood turning, so please accept my compliments in the spirit with which they were intended. I know it must be good because I have faith in you!

- Jerry

DITTO… :)

-- Have Fun! Joe Lyddon - Alta Loma, CA USA - Home: http://www.WoodworkStuff.net ... My Small Gallery: http://www.ncwoodworker.net/pp/showgallery.php?ppuser=1389&cat=500"

View recycle1943's profile (online now)

recycle1943

2717 posts in 1893 days


#3 posted 12-10-2018 12:35 PM

yeah Jerry, I understand
I slept thru most all of my design engineering class while attending MIT but like you I judge from the projects Jim posts that he knows what he speaks of

-- Dick, Malvern Ohio - my biggest fear is that when I die, my wife sells my toys for what I told her I paid for them

View lew's profile

lew

12564 posts in 4026 days


#4 posted 12-10-2018 12:56 PM

Awesome rig! The thrust bearing idea must really make for smooth operation. The lathe to unit mounting is really a cool idea, too.

I’ve thought about doing that with a laser but haven’t really done enough large hollowing to make it necessary.

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

View bushmaster's profile

bushmaster

3524 posts in 2554 days


#5 posted 12-10-2018 03:31 PM

I said great minds think alike on one of your other projects, well you beat me to it again. I also have been working on articulated arm for hollowing. I have one put together and just working on the bar and cutter. I will have to call it No. 1 too as I have another design I will build too. Result of to much time dreaming in the hot tub. Mine will be the same but entirely different from any built.. I will try and get it tested this week and post it next week. I believe I have every thing squared away with the insurance company and will be able to have heat in the shop this week and can get going on projects. Thanks for all the pictures.

-- Brian - Hazelton, British Columbia

View doubleDD's profile

doubleDD

8137 posts in 2314 days


#6 posted 12-10-2018 03:59 PM

Hi Jim. I’m trying to take this all in but I’m not that familiar with the Jamieson system. I did think that the Jamieson seemed a bit bulky but never had the opportunity to try it. This looks like a simpler style. Those bearings should give you a lot more smoothness. Mounting it to another banjo is a good idea, similar to the carter system and makes it easier to set up I bet. If you ever get a chance for a short video I would like to see yours in operation.

-- Dave, Downers Grove, Il. -------- When you run out of ideas, start building your dreams.

View GR8HUNTER's profile

GR8HUNTER

5579 posts in 983 days


#7 posted 12-10-2018 04:10 PM

OH YEAH YOU DESERVE THIS

AWARD :<))

-- Tony---- Reinholds,Pa.------ REMEMBER TO ALWAYS HAVE FUN

View Julian's profile

Julian

1454 posts in 2961 days


#8 posted 12-10-2018 04:16 PM

Nice hollowing rig. I made a similar hollowing rig over a year ago. Mine mounts to the lathe bed; since I don’t have a second banjo. Definitely makes hollowing much easier and safer.

-- Julian

View John Williams's profile

John Williams

19 posts in 2127 days


#9 posted 12-10-2018 06:49 PM

Very nice system! Thanks for your note on my YouTube channel.

John Williams

-- John - www.urbanwoodcreations.com

View Jim Jakosh's profile

Jim Jakosh

22054 posts in 3376 days


#10 posted 12-10-2018 07:02 PM

Hi Lew. I did not have any idea how they worked to run smooth until I took apart the monster hollower and saw the flat thrust bearings. It was easy after that. It is kind of like finding out from you how to cut the celtic knot without all the pieces sliding all over the place.

Hi Brian, I can’t wait to see what you came up with. Are you suing thrust bearings on the top and bottom too?

Hi Dave, the Jamieson system has the bar mounted to a big loop in the back that runs between to parallel bars to negate the torque. I’ll try to make a video yet this year, but it might have to wait until April. This is almost as easy as picking up a gouge to do the hollowing…just takes more storage space.

Hi Julian, do you have a photo of your system n here somewhere? I really like having two banjos. I use them all the time when I have the steady rest on the lathe. I can work both sides of it that way.

Cheers, Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

View splintergroup's profile

splintergroup

2554 posts in 1493 days


#11 posted 12-10-2018 08:16 PM

Way cool!
I first saw this “idea” during a show where David Marks was hollowing am urn. I thought using a laser to show where the cutter was from an outside perspective was neat, but the whole thing looked kinda cumbersome.

Leave it to Jim to reengineer it 8^)

View Grumpy's profile

Grumpy

24942 posts in 4122 days


#12 posted 12-10-2018 11:57 PM

Looks like a very usable tool Jim. I have 2 hollowing tools, one is a ‘Rolly Munroe’ Tool;
https://www.youtube.com/watch?v=c_xhE9dxavo
.
.

.
and the other I bought from a Wood turning teacher who developed his own tools.
It has two good features
The arm parallel to the cutter provides firm support to reduce vibration and tear out and tth other feature is an adjustable depth gauge.
Both tools do a good job even on dry seasoned wood which I mostly use.

-- Grumpy - "Always look on the bright side of life"- Monty Python

View bushmaster's profile

bushmaster

3524 posts in 2554 days


#13 posted 12-11-2018 01:20 AM

Was thinking this afternoon about the bearing you used, no I am not using that type. Seems to me that you could not tighten the bolt too much or it would get stiff quickly. The bolt could not be a tight fit in either the arms or center piece as it is not fitted to the thrust bearing. ?? I have never seen one of the manufactured ones so I do not know what kind of bearing they use. I have looked at different kinds on the webb and of course my parts will be similar. I have got mine ready to test out. finished up a unique boring bar cutter set up. I may go in the cold and give it ago yet tonight. Ran into a snag with the heating system, hooking up the two thermostats. Went skating on the lake this afternoon to give my brain a rest.

-- Brian - Hazelton, British Columbia

View Jim Jakosh's profile

Jim Jakosh

22054 posts in 3376 days


#14 posted 12-11-2018 02:39 AM

Hi Bruce. I feel using the laser is kind of like cheating as it work so well. I found that when I use my laser with the 3 arm steady rest, the laser runs into the top bar, so I made a 4 arm steady rest and it solved the problem.

Hi Tony, that out rigger arm should counter any torque. What cutter do you find works the best for you?

Hi Brian!!The thrust bearings have to be set for just the right pressure to keep them tight , but not too tight. The two at the ends of the straps have a lock nut on the bottom so I just turn them in until it is just right for play and movement. The one over the post had to be set with just the correct height inside that brass hex collar and the shoulder bolt is turned tight to the post. I dialed it in with a depth mike. I demonstrated mine tonight with the laser to a buddy from Illinois. I use a carbide disc set at 22 degrees tilted down for a negative rake and it cut real smooth.

Cheers, Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

View Grumpy's profile

Grumpy

24942 posts in 4122 days


#15 posted 12-11-2018 04:02 AM

Jim, the outrigger as you well named it has a tip the same as the ‘Rolly Munro’ tool.
Here’s a link
https://www.cwsonline.com.au/shop/item/10mm-replacement-tct-round-cutter
Here’s another made by the same teacher!



.
They all are useful depending on the job. The last one I added i good for scraping.

-- Grumpy - "Always look on the bright side of life"- Monty Python

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