Homemade hollowing rigs????

[Dwight McNutt]

Anyone care to give the measurements if the different lengths of each piece, or is a trial and error thing??

[Bob Haverstock]

Dwight,

The sizes depend on the lathe that you are using and the size of work that you are wanting to complete. For example, I built mine to fit my Nova 16-44 with no bed extention. I wanted to hollow 16 inch deep. I built a captures system, luckily, I remembered that the bar also had to extend over a tool rest. I made the working end of the bar 18 inches long. I made the sliding double rodded captured end of the bar 2 inches longer that the depth thatIi wanted to achieve. Remember to consider the centerline in all of your construction efforts. BTW, I built by bar out of 1 inch diameter cold roller steel and use 3/16" square HSS tool bits.

Have fun and be safe.
Bob Haverstock

[Antonio Martinez]

CHeck out Capt. Eddie Castelin video on YouTube. He has 2 on what he calls the steel snake. YOu can also find info here:

http://eddiecastelin.com/yahoo_site_...e.54183757.pdf

[Dennis Ford]

I am attaching a sketch of mine. It is made of 1-1/4" dia steel. The cutting end is bored 3/4" and has two set screws for securing attachments. The two short bars are 1" steel. This design is good to about 18" deep but I should make a lighter one for smaller forms.


hollowing.jpg

[Steve Harder]

I built a steel snake.

I used 1 1/4" receiver tube (for trailer hitch) as a vertical receiver for 1 1/4" square that is an adjustable upright. This is mounted to lathe bed with a flat plate bolted thru bed.

For steel snake portion - 1" square for about 9", bolted up to 1" square for 12", then down to 1" square for 6". This allows entire arm to swivel over top of vertical mounting - so you are not restricted as to which side of upright you are on.

Sort of ___-------_____
..............................._|_...............

Swivel points are thrust bearings with 3/8" bolts as pin with captive nut.

Just make sure drilled holes are plumb and you are in business.

[Hayes Rutherford]

Dwight, here is another direction in hollowing tools that you might consider.

The boring bar is made from 1/2" square stock 15" long.
The side brackets are 1/8" x 2-1/2" strap, they measure 7-1/4" from short point to long point, and are cut on a 30/60 deg. angle. All hole patterns are 2"o.c. 1/4" holes.
The laser support tubing is 1/2" x 10"
The "Y" axis part of the laser adjuster is 5/8" thin wall tubing, and the "x" axis part is the same 1/2" tubing as the support tube. The laser adjuster as made requires some welding.
The captured tool rest is spaced 1/2" x 2 x 6-3/4 steel bars. Some drilling and tapping required.

I have made other bars that are cranked and with scraper cutters but tend to use it in this configuration and use hand held multi axis type scraper for smoothing the inside and use a J.Jordan hooked hollowing tool for very flat shoulders. This will go at least 8" or more and I scaled one up using 5/8" bar that can go 11" or more.

[Jake Helmboldt]

For those of you making articulated systems; how did you drill the holes for the bearings and get them to align properly? I have a drill press but what kind of bit did you use to get as proper hole (i.e. does it matter if it has a flat bottom for the bearing to seat)?

Also, did you use aluminum or steel bar stock?

[Bill Bolen]

If you use thrust bearings between the arms you will not have to drill holes for the bearings to rest in. They just sandwich between the movable joints.

[Jake Helmboldt]

If you use thrust bearings between the arms you will not have to drill holes for the bearings to rest in. They just sandwich between the movable joints.

Thanks Bill, I didn't realize that. Good to know.

[BILL DONAHUE]

Lyle Jamieson has a website and I believe he has plans on it for building his hollowing system. It's a terrific system. Good luck in the big game.

[Eric Gourieux]

If you make an articulated system, IMHO, thrust bearings are essential. You can crank down the bolts at the joints to minimize vertical movement and still have smooth horizontal movement.