Wednesday 22 July 2015

Intonation by defret

It all started as an intonation issue. The strings are very rubbery/slinky and they move a lot.....sooo the action needs to be on the high side. This means the string stretches and plays sharp, so we place the saddle to accommodate this. On this bass the bridge is straight across and the G and D strings are quite flat. Solutions?  Recut the saddle slot, add a piece in front of the saddle, don't play up the neck. A handy piece of maple was wedged between the top and the string as a way of finding the right spot for the intonation to be correct.

The right spot was in front of the bridge. A small piece of walnut was slotted and a two string saddle was made. Although this was better it brought us to the "How do you feel about playing a fretless bass" conversation. The owner was game.

There's a tool thats been around the shop for over twenty years, it's a piece of maple with a sharpened piece of hacksaw blade jammed into a curved groove. It and a hammer cut a curved piece of veneer to fill in a fret slot. It was made in the eighties when making fretted basses fretless was "The Mod". It's gone, it will probably roll out from under a bench or fall out of a box at some point. After half an hour of searching it was time to make a new one. The pictures tell that story but basically a groove was cut in a new piece of maple, a short length of hacksaw blade was sharpened and then stuffed into the groove along with some white plastic binding.  CA glue holds it all in place. (CA short for Crazy Adhesive)

The pieces were cut and then glued into place with Titebond. CA glue is the usual choice in this shop, but not this time. We're not sure why. The tiny plane was used to trim the maple veneer flush and then the whole fingerboard was sanded with 150, 180, 220, 320 ......and then steel wool, 0000 steel wool, the good kind from Lee Valley that doesn't fall to pieces. The Bulldog stuff is so inferior it should be called something else like steelish wool. Or bits-of-steel-that-can't-wait-to-get-everywhere wool. It's the kind of thing you should buy as a gift for someone you don't like.

It was a solution that worked, the customers happy taking on the challenge of playing fretless and the bass sounds better as a fretless. And the shop has a new fretless bass veneer cutting tool. It needs a better name.

Thursday 30 April 2015

Give piece a chance

A badly damaged top requiring replacement of some of the top wood came in. A small section of the side was pushed in and would have to be put back in place and supported. The finish on the headstock veneer was damaged and needed to be refinished. There was a crack opposite the larger one on the bass side of the lower bout that would need a cleat and another smaller one on the bass side shoulder.

The top was marked and then scored using a metal ruler and a sharpened xacto knife. (I like to hone new blades so they're very sharp rather than sharpish) The knife left a very clean and straight edge to glue a patch to. The top was cleared using a small saw that usually cuts out the hole for a side mounted pre amp, it was perfect for this job. The remaining wood was cleaned out using a half inch skew chisel and a tiny micro chisel.
A matching piece of spruce was milled to thickness, a few off cuts from this were put aside to match the finish. The objective at this point was to match the finish first and then cut the patch using an already fitted template. Theory being that this would be a cleaner repair that wouldn't require refinishing the top or a section of the top. It turns out that the water borne finish I was using played well with the Taylor UV finish and spot finishing wasn't out of the question.

The side patch was done first and bent slightly under the curve while the outside caul was made slightly over the curve. This helped get the patch to fit fully and compensate for the small amount of springback. Clamping in place was made easier with the top piece removed.

The top piece was glued in place and further supported with cleats held in place with magnets. The crack on the other side was also cleated and finished. The crack on the bass side shoulder was glued and clamped and then spot finished.

Unrelated damage to the finish on the headstock was repaired by sanding back and applying finish with a brush. After several coats it was sanded flat and polished out.

Another unrelated repair was a broken index pin on one of the machine heads. A small hole was drilled where the index pin had been and a salvaged pin from a Sperzel tuner was pressed in place. The tuner was working like new.

An involved repair with a happy ending.

Saturday 28 March 2015

Old Gtretsch flattop - A bridge too far

An old Gretsch flat top started out life with the saddle a quarter of an inch shy of its scale length. A previous repair, avoided top and bridge plate patching by using a pinless bridge. Sadly it didn't last or work that well, I appreciate the idea though.
The original bridge had nuts imbedded in the top and two screw's that went through the bridge adding mechanical strength to the glue joint. This is important because it meant those holes and the original bridge pin holes needed to be filled, ideally adding some structure at the same time.
Eighth inch thick maple plugs were made with a plug cutter and used to patch the bridge plate first. A template made with a 5/8" inch forstner bit was used with a bearing guided router bit to make the matching hole.
The factory installed birch bridge plate was too soft, it needed stiffness and strength. A one sixteenth hardwood bridge plate was needed to consolidate the bridge area and provide a good surface for the ball ends of the strings to bear against. This would be done before the plugs were put in. A scrap of paper was used inside to crease around the plate edges and braces making a pattern of the bridge plate. When the bridge plate was properly fitted a matching caul was made and the new piece was glued in.
With the maple plug fitting just a little bit proud of the bridge plate surface the whole process was repeated with a 3/4" spruce patch sitting on top of the bridge plate. At this point both of the bridge nut mounting holes and four of the bridge pin holes were filled in.
A new bridge could be made with the saddle in the right place and the new bridge pin holes could be drilled without conflict from the original bridge.
This bridge would be made slightly oversized to allow the saddle and bridge pins to be moved back and a little low to avoid a cost prohibitive neck reset.
A pattern was made using the pinless bridge that had been on the guitar. Then it was cleaned up and made symmetrical with a folded piece of paper.
The pattern was traced onto the rosewood and rough cut with a bandsaw. The top profile was machined with a drum sander and fence. The front profile was created with the thickness sander jig.
*I didn't invent this jig but this is my version of it. I first heard of it from a repairman that I worked with years ago and then saw another version of it on a bow making site.*
With the bridge dry clamped in place the slot was marked and drilled to depth with an eighth inch brad point bit at each end. Now the bridge was ready to be glued in place. The previously mentioned bridge plate caul was used to glue down the new bridge.
With the bridge solidly glued in place the saddle slot was finished and a temporary saddle was put in to check the intonation.
The intonation is spot on and the guitar sounds great, a warm round low end with lots of harmonic wash in the top end. A bit of set up work a new saddle....the guitar that had never played in tune or sounded right did both now.