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Dec 4, 2023 - 1:12:59 PM
74 posts since 3/24/2004

Hello!

I have a nice rim I’d like to take some material off of to get a nice slip fit for a tone ring I have and I was wondering if there was a way that this could be done by hand. I don’t have a lathe, so that wouldn’t be an option.

I’m sure the smartest and best practice would be to just send both to a qualified luthier, but I’m curious if there is a way that anyone has been able to do this without sending it off or without pricey tools.

Any help is appreciated, thank you!

Dec 4, 2023 - 1:53:06 PM

110 posts since 12/26/2019
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You can scrape with a razor blade; it can take a while, but it works (hold the blade at 90degrees to the rim and draw the blade around the circumference shaving off very little as you go

Dec 4, 2023 - 2:18:14 PM
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5516 posts since 5/29/2011

It depends on how much wood you want to remove. If it's a situation where you need to remove more than an eighth of an inch, let a luthier do the job. If it's a situation where you only need to shave off a tiny amount you can probably do the job with a flat file. Or you can start with a rasp, then use a file. I have done that before and it worked quite well.

Dec 4, 2023 - 2:26:17 PM
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martyjoe

Ireland

482 posts since 3/24/2020

Sandpaper is another option you may have to use it with a sanding block.

Dec 4, 2023 - 2:56 PM

306 posts since 12/9/2009

I've heard not to use sandpaper or blocks and only do it by scraping with a blade of some sort. My hands can't take that anymore and I have had several Deerings from the pressed on the rim days. I generally start with a fairly aggressive sanding block and then move to something a bit less so to smooth it out a bit. I'm not a woodworker but it seems like turning it on a lathe would somewhat compare to an aggressive sanding block.

At any rate, I have been satisfied with my own banjos done that way. On the other hand, I'm pretty sure that all the banjos I grew up listening to (I'm over 60 now) were pushed down pretty tight on the rim and they sounded great to me then and now as well. In fact, so good that I decided to invest a fair amount of my hobby endeavors and $$$ into pursuing that sound.

Dec 4, 2023 - 3:10:39 PM
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61671 posts since 12/14/2005

IF you are determined to do it yourself....
Fasten the rim to a piece of plywood (Possible to do without nailing the rim to the wood)
Put a nail in the exact center, nail it to your workbench, mark how far down the rim you have to grind, and then start removing, turning the plywood as you go.

You could even set up an electric drill and a drive belt, to SLOWLY rotate it against your rasp, router, sanding block, whatever.

Always a good idea to have tool stops in place, so you can't cut too far.


"Can always cut um SMALLER, but never can cut um BIGGER!"

-Conan D. Barbarian"

Dec 4, 2023 - 4:33:21 PM
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15695 posts since 6/29/2005

Chances are that ther tone ring skirt is exactly round because it was machined on a lathe. The rim the other hand may not be perfect. 

I would coat the inside of the skirt with graphite from a soft pencil and put it onto the rim, turning it a bit, then take it off and you will see where on the rim to sand off material. It may not take all that much sanding to loosen it.  sanding strips in the width of the part of the rim under the skirt are a good way to do it.

Dec 4, 2023 - 5:04:46 PM

74 posts since 3/24/2004

Thanks for the suggestions and insight everyone!

Dec 4, 2023 - 6:56:17 PM
Players Union Member

Helix

USA

17440 posts since 8/30/2006

1.make friends with some local cabinet makers. They have all the tools you need
Play banjo for them


2. Get a belt sander belt and use it like a shoeshine rag. Reported accuracy of .0001

Dec 4, 2023 - 9:29:10 PM

5516 posts since 5/29/2011

Ken's idea of using graphite is a sound idea. Maybe the rim is slightly out of round and you don't need to take wood off the rim uniformly.
Larry's idea of using a sanding belt is a good one. You can also buy emery cloth in rolls which could be cut to a usable length and used the way he describes. Emery cloth can be found at Home Depot, Lowe's, or some local hardware stores. I think I got mine on eBay.

Dec 5, 2023 - 3:48:14 AM

5366 posts since 11/20/2004

Look closely at the rim edge. Anywhere the ring is tight, it will be shiny. I use a utility knife blade and scrape the shiny areas to get the fit like I want. Be conscious of humidity when fitting. A loose fit when really dry, becomes tighter when humid and also works the other way.

Dec 5, 2023 - 3:58:32 AM
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61671 posts since 12/14/2005

Oh, by the way!
Make a mark on the INSIDE of the rim and tone ring, so you're always trying to fit them together at the same spot.

Dec 5, 2023 - 5:03:46 AM
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beegee

USA

23243 posts since 7/6/2005

I am wondering why it was advised not to use sandpaper? And why was it not mentioned to apply goofer-dust?

Dec 5, 2023 - 5:21:20 AM
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Brett

USA

2576 posts since 11/29/2005

Sandpaper folded, or razor blade.

Dec 5, 2023 - 6:24:23 AM

792 posts since 7/10/2012

Just my two cents... I think the trick to getting a slip fit is a combination of 1) the right curve to align with the curve of the rim (see Ken's advice on marking the top of the rim), 2) the right depth from the top of the rim to the bottom of the rabbet, which you can also measure and mark on the rim along the outside, and 3) crucially a perfectly straight 90 degree angle from the top down along the side of the rim and from the side inward to the inner wall of your rabbet. That straight 90 degree angle is a real challenge and why some folks are recommending not to use sandpaper, which can conform to whatever the shape might be and give you a bulge instead of a straight surface for the rim to 'slip' against.

I think I might take the following approach:
1. Set the ring on top of the rim and mark the outer edge all the way around. I don't imagine you can mark the inner edge you need to cut to because the ring is in the way, but if you can reach that with a pencil and get a clean line, mark the inner cut you will need that way.
2. Measure the thickness of the ring skirt and then mark the inner edge top-cut line inside the outer edge line you already have on the top edge of the rim
3. Measure the depth of the ring from the bottom of the skirt to the inner surface of the ring that will rest on top of the rim and mark that depth around the side of the rim so you have your side-cut line
4. Clamp the rim to a flat surface and use a Japanese saw or the finest tooth, flattest saw you have with the side-cut depth you measured marked on the saw and the saw resting on a 90 degree block as a ledge so it cuts into the side of the rim at 90 degrees and slide the saw across the flat block as you work your way around the rim stopping just short of the desired depth to get your side-cut
5. Clamp a 90 degree block to the top of the rim and make a series of cuts down to the side-cut line all the way around the rim. You will be leaving little points all the way around, but you can address those next
6. Once you have the side-cut and the top-cut both done at 90 degrees each, I'd take a flat file and with the file resting on the side-cut you made, gently take off the points left from the top-cut all the way around so its mostly smooth and definitely still 90 degrees all the way around. Make sure you are using a file that will not cut into the side-cut surface and muck it up
7. Then you can use a long strip of 150 sand paper and gently pull back and forth all the way around to smooth the vertical surface of the rabbet up to the top-cut line you made until the rim starts to snuggly fit around the curve
8. Then you can clean up the corner of the side-cut/top-cut intersection with a razor blade or chisel until the ring sits flush against the top-cut all the way down to the side-cut

Sounds like a fun project, good luck and I hope the end result gives you the tone you are looking for!

Dec 5, 2023 - 6:49:50 AM
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chief3

Canada

1161 posts since 10/26/2003
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I have used a very sharp wide chisel to slowly scrape the wood around the circumference of the rim. It provides lots of control and the scrapings are very fine and even around the rim if you use light pressure and go slowly.

Dec 5, 2023 - 2:07:40 PM

jonc

USA

473 posts since 10/23/2014

I've done it with sandpaper but it wasn't perfect and it was taxing. If I were to do it again I'd rig up a turntable and mount some sort of gizmo with spring tension holding the sandpaper against the wood. Then turn all day.

Hey, get a cheap exercise bike from Craig's list and mount your rim to the flywheel.

Having a luthier do it isn't necessarily going to be better. I've had rims from Stew Mac that were fit terribly. When I took the tone rings off the rims were cut to a slope so the only contact was around the bottom.

Depending on where you live, it would be good to do this in the winter and the rim will swell the rest of the year. So if you go a little small you'll have some leeway. Also heat your tone ring before you fit it, and as you check the fit. Then when it cools it will shrink a little bit. I placed mine upside down on a griddle to remove a super tight ring and it came right off once it got hot.

Dec 5, 2023 - 2:29:38 PM
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jonc

USA

473 posts since 10/23/2014

I almost forgot, get a couple packs of emery boards from Walgreen's cosmetic section, very handy to have sandpaper on a convenient stick.

Dec 5, 2023 - 2:30:10 PM
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beegee

USA

23243 posts since 7/6/2005

quote:
Originally posted by Society Hill

I've heard not to use sandpaper or blocks and only do it by scraping with a blade of some sort. My hands can't take that anymore and I have had several Deerings from the pressed on the rim days. I generally start with a fairly aggressive sanding block and then move to something a bit less so to smooth it out a bit. I'm not a woodworker but it seems like turning it on a lathe would somewhat compare to an aggressive sanding block.

At any rate, I have been satisfied with my own banjos done that way. On the other hand, I'm pretty sure that all the banjos I grew up listening to (I'm over 60 now) were pushed down pretty tight on the rim and they sounded great to me then and now as well. In fact, so good that I decided to invest a fair amount of my hobby endeavors and $$$ into pursuing that sound.


My 28 Granada AT always sounded a little "constipated. " Several years ago, I decided to re-fit the ring. It was so tight, I had to pry it off with wedges and small screwdrivers. I used a small rasp for the initial treatment, followed by various grades of sandpaper and even some Dragon-Skin metal "sandpaper." When I got it to where I could pry it off by hand, I used a properly-sharpened  card-scraper to smooth it out until I could remove it easily by hand, but it wouldn't fall off when the rim was inverted. 
The result was a lot more resonant "open" sound, more complex over-tones and more volume. I'm glad I did it, but the caveat is to work slowly and carefully. 

I reckon I should have saved that pre-war sawdust...

Dec 6, 2023 - 7:44:18 AM
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RBuddy

USA

1789 posts since 7/2/2007

An easy way to sand the shoulder without it getting wonky -

Cut a strip of wood the height of your shoulder. Glue or double stick tape some 80-100 grit sandpaper to it. Clamp it to a work surface. Rub the rim against it. It will keep everything flat, square and uniform.

https://www.banjohangout.org/photo/301063

Why are pictures harder to post than they used to be??? Sorry you have to follow the link.

Note - the picture was just a quick setup for demo, I'd cut the sandpaper better for the real deal.

Edited by - RBuddy on 12/06/2023 07:45:55

Dec 6, 2023 - 7:56:07 AM

74 posts since 3/24/2004

Some really amazing and innovative ideas here, thank you! I love the idea of using an exercise bike! cheeky

Edited by - looped77 on 12/06/2023 07:57:26

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