Cutting binding channels

C

ChuckBarnett

Well-known member
Joined
Mar 3, 2017
Messages
490
Reaction score
3
Location
Arlington, WA U.S.A.
I got the thing boxed in!! :)

Now addressing binding and I have some questions as I research how to go about this.

I've no need to consider speed given that 'production' isn't a concept I've any clue about thus far. I have a Bosch laminate router and tilt base. I figure on buying a bit and some bearings (2 is all I need at this point...) and doing the hand-held method. Yes??

Question 1: Are bearings sold by Stew/Mac, LMI, etc. interchangeable with binding cutter routing bits?

Question 2: Do you/should I used a 'gramil' tool to score the edges of channels before routing them? (In this case I am working on a redwood top and quilted maple sides/back.)

Question 3: The sides are not perfectly round in places -my hand finds out-of-round spots. And there is roughness that somehow should be reduced? Else the bearing cannot be expected to produce a nice channel, no? Not sure how to address this.

Question 4: It looks like the back somehow protrudes longer at the bottom end than the top. This makes the angle between back and sides at the end wedge less than 90°, and it is obvious to the eye. Is this fixable? I’d think it would affect binding.

Question 5: The Koa binding I've made varies in thickness from .057 to .062 inch. I used a drum sander to reduce it down by taping all 4 strips onto MDF (leaving 1/4" or so between. I cleaned up bandsaw marks and flipped them over to do the other side. I plan to install them deep and bring the sides to the bindings rather than scrape/sand the bindings to the sides. Will this much variation work?

Blessings to any and all who believe there is hope for me! :)
 

Attachments

  • Boxed in 1.jpg
    Boxed in 1.jpg
    97.4 KB · Views: 92
  • Boxed in 2.jpg
    Boxed in 2.jpg
    94.6 KB · Views: 87
ChuckBarnett said:
I got the thing boxed in!! :)

Now addressing binding and I have some questions as I research how to go about this.

I've no need to consider speed given that 'production' isn't a concept I've any clue about thus far. I have a Bosch laminate router and tilt base. I figure on buying a bit and some bearings (2 is all I need at this point...) and doing the hand-held method. Yes??

Question 1: Are bearings sold by Stew/Mac, LMI, etc. interchangeable with binding cutter routing bits?

Question 2: Do you/should I used a 'gramil' tool to score the edges of channels before routing them? (In this case I am working on a redwood top and quilted maple sides/back.)

Question 3: The sides are not perfectly round in places -my hand finds out-of-round spots. And there is roughness that somehow should be reduced? Else the bearing cannot be expected to produce a nice channel, no? Not sure how to address this.

Question 4: It looks like the back somehow protrudes longer at the bottom end than the top. This makes the angle between back and sides at the end wedge less than 90°, and it is obvious to the eye. Is this fixable? I’d think it would affect binding.

Question 5: The Koa binding I've made varies in thickness from .057 to .062 inch. I used a drum sander to reduce it down by taping all 4 strips onto MDF (leaving 1/4" or so between. I cleaned up bandsaw marks and flipped them over to do the other side. I plan to install them deep and bring the sides to the bindings rather than scrape/sand the bindings to the sides. Will this much variation work?

Blessings to any and all who believe there is hope for me! :)
Click to expand...

Well that is a lot of questions there. I can't really answer them all as I use different tools but:

2) No gramil needed if you use a router.
3) When you say not perfectly round do you mean square to the top?
4) I don't really understand this question. Sorry.
5) Variation in binding thickness won't matter as long as your channel is only as deep as your thinnest part of the binding. It all scrapes and sands out in the end. If the channel is deeper than the binding thickness than you have a problem which means you will have to scrape down the side to get flush. Do not go there.
 
ChuckBarnett said:
I got the thing boxed in!! :)

Now addressing binding and I have some questions as I research how to go about this.

I've no need to consider speed given that 'production' isn't a concept I've any clue about thus far. I have a Bosch laminate router and tilt base. I figure on buying a bit and some bearings (2 is all I need at this point...) and doing the hand-held method. Yes??

Question 1: Are bearings sold by Stew/Mac, LMI, etc. interchangeable with binding cutter routing bits?

NO. The inside diameter of each of their bearings matches their particular cutter and they are not the same. I have both.

Question 2: Do you/should I used a 'gramil' tool to score the edges of channels before routing them? (In this case I am working on a redwood top and quilted maple sides/back.)

Not required. Some may use a coat of shellac to firm up the soundboard if it's spurce or cedar to help get a clean cut.

Question 3: The sides are not perfectly round in places -my hand finds out-of-round spots. And there is roughness that somehow should be reduced? Else the bearing cannot be expected to produce a nice channel, no? Not sure how to address this.

Fair your sides to the best you can prior to cutting the binding channels. Scrapers, sanding block etc. Some find it helpful to first use the cutter with a smaller bearing to relieve the top and back so there isn't as much material to remove, and then come back with the correct bearing and clean up the rebate.

Question 4: It looks like the back somehow protrudes longer at the bottom end than the top. This makes the angle between back and sides at the end wedge less than 90°, and it is obvious to the eye. Is this fixable? I’d think it would affect binding.

This is one reason some use a cradle to hold the instrument so the sides are as close to perpendicular to the bench as possible and then have the router in a stand that follows along the soundboard. You may be able to finess the rebate afterwards with chisel and file. Or in this case perhaps the Gramil would be your friend.

Question 5: The Koa binding I've made varies in thickness from .057 to .062 inch. I used a drum sander to reduce it down by taping all 4 strips onto MDF (leaving 1/4" or so between. I cleaned up bandsaw marks and flipped them over to do the other side. I plan to install them deep and bring the sides to the bindings rather than scrape/sand the bindings to the sides. Will this much variation work?

I'd suggest you shoot for installing the bindings as close to the sides as possible and take any high spots off the bindings rather than the other way around. It's far more diffucult to do it the way you are suggesting. Remember that when you heat bend timber bindings and then add glue to them they will swell a bit. For your reference I use 0.080" for the rebate for my bindings, but I make the 0.070 prior to bending and glueing in place. They end up dry with virtually no leveling needed. Just a clean up of glue squeeze out (hot hide glue) and a round over of the edge.



Blessings to any and all who believe there is hope for me! :)
Click to expand...

Good luck with this.
 
ChuckBarnett said:
Thank you for taking time to post on this overblown list of questions. I missed where this link discusses what I was asking.
Click to expand...

It answers a question about binding that you didn't ask, and Allen refers to in question #4. Maybe not the answer you wanted, but certainly a doable means to assure accuracy and success.
Also, I'm thinking you're not set on a process just yet, so just throwing options your way.
ChuckBarnett said:
. . . as I research how to go about this.
Click to expand...

Hand jobbing a router against a flat top is okay. Doing it on a non-flat back without a reference to the sides is something that would normally be discussed in other forums on the Underground.

Personally, I'd love to get one of these http://www.luthiertool.com/self-aligning-binding-cutter.html

Or you can do it how Taylor does it. . . https://www.canadianluthiersupply.com/products/binding-jig

But this is the one that led me to using a Zero Bar for my now custom bearing foot. https://elevatelutherie.com/product/ultimate-binding-jig/

Note: I wouldn’t expect $$$ to be dropped on the jigs, but hopefully they give you ideas of how you can mitigate some of the issues you have. If you haven’t gone through the thread linked in post number three, you’ll see some solutions to processes that sometimes are adequately addressed with your own jig.
 
Last edited:
Great links Kekani, but for the amatuer, first time builder that the OP is, I think all of these methods/tools bearing foots are severe overkill. These are really fine tools but not needed to do a decent binding job. I would love to have these kind of set-ups, but I think they are aimed more at the production type builder than the amatuer. I just use a hand held dremel and a Stew-Mac base with a 20$ router bit and it works great. Zip, zip, zip. Glue, glue, glue.
 
Allen, did you mean cutting initially with a smaller bearing to fair the sides? I use the largest bearing and a shallower cut before fairing. Maybe my set up is different. Am I missing something?
 
I started investigating how to do binding 2 months ago! I may not be fast but I sure am slow! :)

Didn't want you all to be disappointed in not hearing from me for so long so I'm just going to put some photos up and say that I am fairly satisfied with how this turned out . Cannot come up with enough ways to say thank you for your help!!
This feels like it was a pretty important step. I know there are more challenges to come but I'm pleased with this progress.
 

Attachments

  • 20181024_083337.jpg
    20181024_083337.jpg
    97 KB · Views: 48
  • 20181024_084011.jpg
    20181024_084011.jpg
    94 KB · Views: 46
First time I did the purfling/binding channel with a router was last month. I borrowed a Dremel and the stewmac base. I knew of the domed back/soundboard issue so I worked out a way of negating it. Seemed pretty logical to make the soundboard and back flat again, which I did with some spare soundboard material, scooping it out so that when it was laid on the back it appeared flat. It was. Took me about an hour to make each pattern. The result with the Dremel was excellent. I used a downcut spiral bit.
 
Last edited:
Michael N. said:
First time I did the purfling/binding channel with a router was last month. I borrowed a Dremel and the stewmac base. I knew of the domed back/soundboard issue so I worked out a way of negating it. Seemed pretty logical to make the soundboard and back flat again, which I did with some spare soundboard material, scooping it out so that when it was laid on the back it appeared flat. It was. Took me about an hour to make each pattern. The result with the Dremel was excellent. I used a downcut spiral bit.
Click to expand...

Michael, I'm trying to picture this in my mind's eye. Perhaps did you capture this in a photo or two?
 
I don't think a picture will show it or make it any clearer. You are simply producing a negative of what's happening on the soundboard (or the back) - the soundboard and back of the instrument being the positive. Given that the soundboard and back are domed the underside of your negative is scooped out or carved to match the dome of the soundboard or the back. It's this underside or scooped out surface of the negative that sits on the back. The top or upper surface of the negative is left flat - this is the surface that your router sits on. It's effectively made your back and soundboard flat instead of being domed. As such the router is now square to the sides, none of that tilting that you get with domed plates.
Most doming on an instrument is no more than around 4 mm at maximum height. So your negative needs to be material a bit thicker, perhaps 6 or 7 mm. The carving to match the dome only needs to be approximate, not an exact fit. Of course it also needs to be a few mm's smaller (all round) than your soundboard. I just taped it onto the soundboard. When the router reached the tape I stopped and repositioned it.
Hope that's a bit clearer. If not let me know. I only came up with the solution because I was having hand issues and I didn't want to buy the routing gear. It did work well. With it being a Dremel I used a new downcut spiral bit and did a few passes. They are obviously a bit underpowered but it cut cleanly. that may have been different if I had tried to do it in one pass.
 
You must log in or register to reply here.

Similar threads

Matt Clara
Seal coat before cutting binding channels?
Replies
11
Views
2K
Matt Clara
Matt Clara
Matt Clara
Cutting binding channels on a solid lined uke?
Replies
4
Views
700
Bradford
B
Matt Clara
Router, dremel, laminate trimmer for trimming tops and cutting binding channels
2
Replies
30
Views
10K
thistle3585
T
tonewood
Cutting Binding/Tolerances
Replies
18
Views
1K
BR Ukuleles
B
bluesuke
Cutting binding
2
Replies
28
Views
5K
saltytri
S
Top Bottom