Making a bigger banjo

[Lee Alkureishi]

Hi all,

I recently upgraded my PM90 with some riser blocks, giving me a new swing of nearly 20". Woohoo! Haven't turned anything close to that yet, but it's coming...

Meantime, I've been on the lookout for a bigger banjo to make use of the extra swing. Can't afford a Oneway right now, and the used market hasn't turned anything up yet. I'm an impatient sort, so I figured I'd have a stab at making one instead... So, here's goes!

245745

I found some 3" x 3" angle iron, 1/2" thick, at my local scrappie. I used this as a base for the new banjo, with some additional pieces welded at the ends to give some added rigidity. For the tool post holder, I used the end of a scrapped olympic barbell. Cut that in half, and welded it to the base. To simplify the design, I made the cam-lock handle exit at the rear of the banjo rather than try to somehow bring it through the barbell piece. The camlock handle will either be bent, or will have a little slide handle added - not sure which yet.

245746

For the camlock, it's really just an eyebolt which is raised and lowered by rotating an off-centre shaft. This shaft was made by bolting a 5/8" round rod to the inside of a 1" O.D. pipe.

Up:245747

Down: 245748

Only one question: Before I cut the barbell piece, I thought the I.D. of the tube was 1-1/8", with a wall thickness of about 3/8" - perfect for my existing toolrests. But, when I cut that thick end off, I realized that the rest of the tube was only about 3/16", and the I.D. of the tube is now 1.55". I think the tube is still plenty strong to hold the toolrests, but can anyone suggest what would be the best way to reduce the diameter of the tube? I'm thinking a long split bushing is in order, but where would I even get one that reduces from ~1.5" to 1.125" ? Or, does anyone have any other suggestions to make this work?

Thanks,

Lee

[Lee Alkureishi]

Almost forgot: the dimensions are 18" long (not including the handle), the base is 3.5" tall, and the tool rest holder stands at 7" from the ways. In retrospect, this banjo is probably overkill for a 20" swing, but I guess that's not too much of a problem... The thing I don't like is the height of the base - the stock 3520b banjo's base height is 2.5", which would be a lot nicer. But, my metalworking skills aren't up to creating a cam inside that small of a cavity... In fact, before this project, my metalworking skills didn't exist!

A couple more pics:

Tool post holder:

245749

The Screw in the pic will be replaced with something with a little more leverage :)

A little spray paint action:

245751

245750

In the background is my in-progress steady rest - I'll post a couple of proper pics in the next couple of days :)

Cheers!

[Kyle Iwamoto]

A brand new PM 3520 banjo is 261 bucks. Should fit your lathe... If it don't, it seems to me you could make it fit.

That is a hefty banjo. You may have clearance issues.

[charlie knighton]

interesting, keep at it, does not sound like you have spent $261 yet, i imagine things will improve with new verions

[Dennis Ford]

A nice feature of home made accessories is that you don't have to be afraid of making changes. I suggest that it would be better to cut off the vertical tube and replace it with a tube that fits your tool rest post instead of scrounging a sleeve.

[Bob Bergstrom]

I think the tool post area is a concern. It will be the furthest From the support of the ways with all the forces of the tool on it. The tool post should be as thick as you can make it. When I turn 20" plus bowls on my 3520 even that banjo is a subject of vibration. You just can't have enough banjo support.

[Jeff Nicol]

Lee, I have done all of this work for a fellow creeker but am now out of the business, but what I used for the tool rest post holder is a piece of heavy wall pipe that is already bored for the 1.5" tool posts that are original to the PM 90, but I made tool rests that had 1" posts so he could buy other tool rests available on the market. So here is just a quick reference to look at here for thicker walled pipe and what you would want is SCHEDULE 40 that is about 3 3/4" O.D. with about 1/2" thick walls for great strength.
http://media.wix.com/ugd/861139_bbd2ee19e96d9f776b15045160f291ad.pdf?dn=US% 2BTube%2BSupply%2BPipe%2BSchedule%2BChart.pdf

Have fun and a Happy Thanksgiving,

Jeff

[Lee Alkureishi]

Hi Jeff,

Thanks so much for the reference - I'll give them a call tomorrow :)

Quick question, though - If the O.D. is 3 3/4" and the wall thickness is 1/2", wouldn't that give an I.D. diameter of 3 1/4" ? I'm thinking I'd need a pipe with O.D. of 2" and wall thickness of 1/2" for a 1" tool post, or 2 1/8" O.D. for my original 1 1/8" tool posts?

Thanks again,

Lee