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FiddleDoug

Spiral Bushings

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OK, here's a pictorial on how I do spiral bushings. This is what works for me, and should not be considered to be the "Bible of Spiral Bushings". I know that the use of Titebond is controversial, but the next luthier to put bushings in can easily ream out what I've done and do it the way that they like. The open time of the Titebond allows me to get the bushings into place and set them to the taper.

Figure 1 shows the form that I use to make pre-made spiral bushings from "Red rope folder" material. An appropriate sized piece of material is saturated with glue, wrapped around the mandrel, wrapped in thin plastic, clamped in the form, and the mandrel is removed. This takes a day or two to dry before removal from the form. These are then glued into the over sized peg holes and trimmed. The form is one that I made, so don't ask where to get it.

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Figure 2 shows the mandrel and bushing in the form.

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For maple spiral bushings, I do the large and small ends of the hole separately. The shaving is saturated with glue, wound counter clockwise as viewed from the peg head end,and inserted into the hole. Insert the mandrel into the glued bushing and turn counter clockwise. This will expand the spiral to fit the hole. Remove the mandrel and let dry.

Figure 3 shows two small ends finished.

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Figure 4 shows a maple shaving in the correct winding orientation for the large end of the G.

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Figure 5 shows the glued spiral in the peg hole.

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Figure 6 shows the spiral expanded into the hole.

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Figure 7 shows the expanded spiral with the mandrel removed.

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Figure 8 shows four large end spirals in the peg holes drying.

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Figure 9 shows trimmed, but not reamed bushings.

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I'd certainly welcome anyone else to chime in here with different, or improved methods. We can all learn something!

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Doug,

Thank you thank you thank you thank you!

Now, for the enevitable questions :

-I'm having trouble getting my paper bushings tightly wrapped. I am glazing both sides of the paper prior to wrapping (for full saturation) and then wrapping _ around my plastic mandrels. Because of the glue, the tendancy is for the paper to unwind even as I roll it up. I countered the problem somewhat by rolling the paper towards the small end of the mandrel and then pushing it down towards the big end (compressing the roll somewhat) . Do you have a better method for a tight wrap?

-The end result thus far is a bushing that looks like a spiral. In other words, each successive turn is a little lower on the mandrel then the previous one. If the only part of the bushing that fits into the peg hole is the "spiral end ", will this cause problems later?

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....For maple spiral bushings, I do the large and small ends of the hole separately....

Do you let the glue on one end dry before putting the bushing in the other end? If yes, which end do you do first?

Nice pictures. Thank you.

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Doug,

Thank you thank you thank you thank you!

Now, for the enevitable questions :

-I'm having trouble getting my paper bushings tightly wrapped. I am glazing both sides of the paper prior to wrapping (for full saturation) and then wrapping _ around my plastic mandrels. Because of the glue, the tendancy is for the paper to unwind even as I roll it up. I countered the problem somewhat by rolling the paper towards the small end of the mandrel and then pushing it down towards the big end (compressing the roll somewhat) . Do you have a better method for a tight wrap?

-The end result thus far is a bushing that looks like a spiral. In other words, each successive turn is a little lower on the mandrel then the previous one. If the only part of the bushing that fits into the peg hole is the "spiral end ", will this cause problems later?

Are you cutting your paper in an arc to compensate for the taper? I don't seem to have the sliding problem with the tapered form. If you make the bushing long enough, you should be able to get non-spiraled through the whole pegbox.

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Do you let the glue on one end dry before putting the bushing in the other end? If yes, which end do you do first?

Nice pictures. Thank you.

I guess that I have a tendency to do the small ends first. I do let them dry, and trim them before doing the large ends(makes room in the pegbox for the second bushing.).

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Doug,

Thanks for the cutting tip. The arc solved the problem to a degree by reducing the exposed spiral overlap. (thereby allowing more flat paper on the outside). I made a template that I use for all the subsequent bushings.

I'm still having trouble with getting them tight. I'm not sure how critical this is as I can see that the glue (Tightbond II) will fill any gaps and be extremely hard once fully dry. Of course, that being said, I still feel like they should be tighter. I experimented a bit by rubbing off some of the glue that will be making direct contact with the mandrel and that seemed to help. It might even help to blow on the rubbing-off area to make the glue somewhat tacky before beginning the spiral. I'll try that next. Perhaps someone else here has gone through all this before and has a fool-proof method?

Thanks again for the tutorial. I know it's not easy to put together with so many other responsibilities to take care of first. For me, with three violins needing this fix, it's worth a lot to me.

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... just to add my 2 cents worth...

1- I cut the paper into an arc strip .. inner radius of 23cm and outer radius of 26.5 cm ... That compensates for the taper of the peg.

2- I use Japanese mulberry paper... Mura Koban Kozo paper 45 gm weight. 

3-I make the  bushings without a form and with hide glue... I estimate the length of paper strip that I need to get the thickness of the bushing that I require then tape the end of the paper strip with a small strip of masking tape to a small diameter peg coated with wax. Then laying the paper (with the peg attached) on a slat in my vice, I slop hide glue onto the paper and roll the peg with some pressure against the slat so that the glue is pushed out from between the layers of paper and at the end, I simply roll the peg forward a few times aginst the slat to create a flat finish. Let the bushing dry on the peg and when dry,  twist the peg out of the bushing. The wax keeps it from sticking.

I make a variety of sizes of bushings so that when I need one, I can just test fit to find one that fits nice & snug as a press fit. Before I glueing, I trim the bushing so that the end on the inside of the peg box is flush with the peg box wall.. then glue it in with  hide glue, and now  I only need to trim the outside.

 Cheers... Mat

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Here’s a shot of my homemade bushing maker. Super simple , nylon shafting drilled and reamed , I use brown paper bag, cut in a arc, soak in hot hide glue for a few seconds, twist one up and slip it into the counter form , just need to let it sit a few minutes to let the glue set , then pull it out and off the mandrel for drying. Works a charm. I have a few counter forms , of larger sand smaller dia. So I can make a variety of sizes. Pre test before glued, I can adjust the paper length  to just fit . image.thumb.jpg.cc0c33b4e1eb1dbf5f1122b8c6997214.jpgimage.thumb.jpg.124e1f70c3476adc037ee7a076ef4f9a.jpg

 

image.jpg

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