Thread: #1 Acoustic Build

Are you talking about the butt strip at the lower bout end of the instrument? Youre bending material so obviously youre not. Im just trying to fathom out why you need to fit the binding before the back goes on.

Which method are you following?

Cheers Martin

G'day Martin,

I didn't explain that too well, I can understand the confusion.

The butt strip is the part that I'm fitting at the moment (prior to gluing up the back) but I decided to get the side bindings bent up before I glue in the butt strip. I'm doing it this way as I wanted to make sure I'd be able to successfully bend the side bindings before committing this piece of timber to the butt strip. Looks like the cautious approach payed off in this instance as I might need to select a different piece of timber for the bindings.

My question pertains to cutting and bending the side binding strips. I'm using a local recycled hardwood.

I'm following Chris Wynne's method from his DVD set for this build.

Steve,
I think your problem is grain run out or sloping grain in the hardwood. As you suggested you need to find pieces where the grain is parallel to the edge. Your recylced hardwood may also be a bit brittle or could have been kiln dried. This will reduce it's bending ability.
regards
Steve

Thanks Steve.

I cut another set of bindings, again quartersawn but not nearly as nice a piece of timber as the first, ensuring the grain was parallel along the binding and they bent no problem at all. So I progressed onto the butt strip.

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I'm actually getting to like this binding more than the first set as it commands no attention and should allow the Blackwood to stand out on it's own. (Says he who may have gone just a little overboard with the Purple Heart trim all over the amp head and cab... )

Once the butt strip was glued up I sanded a bevel on the back edge of the sides and lined up the back for marking out the brace locations.

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Notch the sides tomorrow and then the back is ready to be fitted.

Despite the rain I've managed to keep the humidity in the shed down to about 48% today with the little A/C so the back has been glued onto the sides and will stay clamped overnight.

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The back attachment has been completed successfully and trimmed to size with just a couple of minor issues.

Looks like I needed a little bit bigger angle on the neck block to back join or maybe I should have clamped it down a little harder. Didn't notice it at the time unfortunately but will remember that for the next one.

Also had some trouble when trimming with the flush trim bit tearing out a little piece from the back. It should be removed when the binding is done but if it's too deep I might have to add a purfling strip inside the binding. Not sure yet.

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Finished off today by fitting the side bracing strips and centre strips, both cut from the same Spruce as the back bracing.

Starting to take shape now.

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That's a nice looking guitar you've got going there. I started using a shear cut router bit to eliminate the grain tearout you experienced. The bit I use is made by CMT and is a fairly large diameter for the job. I also run a strip of masking around the sides for the bearing to ride on and leaves a slightly proud edge that's easily sanded flush. I also climb cut on those portions that the router is going against the grain, seems to work, haven't had any tearouts yet. Anxious to see your guitar when completed.Mike

Originally Posted by Heartstrings

That's a nice looking guitar you've got going there. I started using a shear cut router bit to eliminate the grain tearout you experienced. The bit I use is made by CMT and is a fairly large diameter for the job. I also run a strip of masking around the sides for the bearing to ride on and leaves a slightly proud edge that's easily sanded flush. I also climb cut on those portions that the router is going against the grain, seems to work, haven't had any tearouts yet. Anxious to see your guitar when completed.Mike

Watching the direction you go with the cutter relative to grain direction is the most effective way to minimise tear out. If you get the Stewmac catalogue theres a nice little diagram in same that explains it all.

Wrapping masking tape around the bearing to leave a slightly proud edge is probably a waste of time if youre going to be cutting a rebate for the binding.

Thanks Mike and Martin.

Now that you mention the climb cutting over various sections I do recall that from the StewMac ukulele kit instructions. I'll have to go back over it before I trim off the soundboard.

One other thing I noticed when trimming the top is that the router bearing left a significant mark in most places around the sides. I suspect it was due to the fact that I was using a cheapo flush trim bit and the bearing was probably just turning with the bit. I'll get a "real" one before I go near the soundboard.

Originally Posted by stevemc32

Thanks Mike and Martin.

Now that you mention the climb cutting over various sections I do recall that from the StewMac ukulele kit instructions. I'll have to go back over it before I trim off the soundboard.

One other thing I noticed when trimming the top is that the router bearing left a significant mark in most places around the sides. I suspect it was due to the fact that I was using a cheapo flush trim bit and the bearing was probably just turning with the bit. I'll get a "real" one before I go near the soundboard.

That's another reason I use the masking, I probably should have said that I apply the tape to the sides of the guitar not the bearing itself. The larger diameter cutters have a broader bearing than the smaller ones which helps to prevent those marks. I use tape with a light adhesive so it doesn't pull any wood off when removed. I've got a binding bit from StewMac but it's a straight bit and tears out. The bearings for it fit the CMT shear bit, so if I'm using binding I just switch bearings after trimming the top, then cut the channel, pull the tape off and I'm done. No marks left like you mentioned. Try it on some scrap and see if doesn't help.Mike

Thanks Mike, I'll give it a go.

I just noticed that the StewMac bit and bearing set now comes with a down shear bit as well and it's not unreasonably priced compared to the local stuff...

Originally Posted by stevemc32

Thanks Mike, I'll give it a go.

I just noticed that the StewMac bit and bearing set now comes with a down shear bit as well and it's not unreasonably priced compared to the local stuff...

I saw that in their catalog, though I wish they would improve their bearings. The set I purchased with my bit are really rough and the edges are sharp, without something to protect the wood they are sure to leave a mark, which I found out the first time I used them. Had to do a lot of sanding to remove the marks, fortunately it was an electric guitar so I could sand as much as needed to remove them. I found that tip on using tape somewhere online, can't remember where, but I found it to be affective. Hope it works for you.

I got my set from LMI and quality of bearings is ok and I dont have issues with marks being left on the side of the guitar.

Thanks again guys.

Just checked out the LMI set and they do seem to be better quality with the steel ring pressed around the outside of each bearing. Quite a bit more expensive though so I decided to go with the full set from SM for the same price as the short set from LMI. Might spend a little bit of time running some wet and dry paper over the edges of the bearings to make sure there's no rough bits.

A bit of minor surgery has kept me out of the shed for a while but got back in there this afternoon and glued up the neck splice, nice easy work only for today.

Attachment 152990

I'd like to press on with the soundboard as well so the next step is to sort out the rosette. I've gone for a Mulga fretboard, bridge and headstock plate but didn't have a piece correctly sized to cut a rosette from so decided to use a piece of NSW Rosewood that I received as a sample from Stopper. It really smells great but sends the wife into fits of sneezing if she gets near it. Don't think I could use it for full back and sides.

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