sMg Guitars

January 9, 2011

I posted the following question on a Luthier Community Forum.

I use an 18″ Grizzly Drum Sander to thickness backs and sides.  I use 100 grit paper, keep it clean, advance mere micro millimeters for each pass yet still can’t avoid burning.  Any suggestions?  The feed rate has been tested from slowest to fastest, yet it doesn’t seem to make a difference.  The harder the wood, the more prone it is to burning.  Must
I accept burning as part of the process (I can scrape it off in the end)?

• My first thought is that the belts are moving too fast.  Can you adjust the speed of the belts??  I assume that the feed pressure is appropriate given that  you are able to adjust the thickness w/o difficulty.  100 grit is fairly common in this application.
• Are you sanding with the grain? Sanding with the grain on high resin woods can cause burning. Try sanding at an angle against the grain. The greater the angle the better.
• I have a Performax 16-32 and found out early on that you need to use a heavy grit (80 or lower) to take the initial pass.  After you have removed a bit, go to 100 or higher.  This works very well for me. Also, with high resin woods, the paper will not gum up as quickly.  If you try to remove the wood with a higher grit, it will  burn and gum up.  Use a heavy grit to remove the bulk of it, and go to a higher grit to smooth it out.
• A dust collector of adequate CFMs is a must.  That would be the first thing I’d look at.  You have to get the dust out of there efficiently as the sanding is happening in order to prevent clogging of the abrasive.  If you have a good dust collector on there, then the problem could be the design of the sander – how well it’s designed to maximize dust removal.  I have a Woodmaster, which excels in this regard.
• I use the little Performax (10-20) so I have to pass on each side to thickness a plate.  I have never had a problem with burning, but I keep my sanding belt really clean (I have a sanding “eraser” next to it and use it about every 4th pass) and use a Grizzly product that comes in 10′ or 30′ rolls for about 4 bucks.  It fabric backed and doesn’t loat much anyways.  I get 3 out of the small one, if I’m really careful cutting.  Also, when wrapping the drum I don’t go right up tight to eachother, but leave a little gap of about 3mm.  I find that any dust not pulled into the hose lodges in there rather than the grit.  I’ve done Sitka and Englemann spruce, and the hardwoods from mahogany to ebony, no issues.  Hope this helps.

November 23, 2010

Today is a snow day, which means I don’t have to work!  Work being teaching math at a high school.  The power is still on, so my power tools and lights work down in the shop, and I’ve got lots I can work on.  I’m juggling several projects right now, a koa dreadnought, a bubinga uke, and a new entry, a palo escrito hybrid with my first cutaway.  I’m also supporting an intern who is working on a walnut OM.  In addition, I’ve got lots of workshop organization and cleanup to do.

I introduced a new power tool into my garage; a planer.

I moved the compressor to a temporary location to make room for the planer, merely delaying the inevitable; where do I put the compressor?

Anyway, minor issues, lots of work available to choose from, and I’m damn excited.

November 21, 2010

New toy purchased this weekend.  I found, at a very reasonable price, a used planer for my shop.

October 7, 2010

Oooh, more wood to play with.  Just got this myrtle today.

July 6, 2010

Well finally, a long awaited repair is complete.  I tackled a neck reset on this Gretsch New Yorker, which I took in 6 months ago.  It was the first attempt to steam off a dovetail neck and reset with the proper neck angle.  I must say that it is a fine result, and it sounds and plays much finer than what I started with.

There was the unfortunate issue of a new side crack due to the removal of the neck (previous neck reset was glued much too muchly).  But I was able to reset the crack and repaint the sides to hide the slight damage done with the neck removal.

A little black lacquer after careful crack filling made this unfortunate blemish disappear.

The previous neck reset added lots of shims and such, but eventually the neck bowed and the guitar became unplayable.  I was able to restore the proper neck angle, yet there’s still a bit of a down movement to the fretboard from 14 to 20.

The end result is a guitar that plays very well, with a reasonable clean up of the mishkabibble from the new crack from the neck removal.

I’m hoping the owner will find it eminently playable.  Not necessarily beautiful, but better than it arrived.

June 15, 2010

I was in Dusty Strings Saturday picking up a few odds and ends and ogling the stock.  I overheard that ukes are big sellers.  The fastest growth in sales over any other item within the store.  I’ve often considered building ukes, and get plenty of signals that this would be a good endeavor.  Not that a uke would be that much faster to build (it’s just a tiny guitar after all), but there may be a larger market out there to support sales.

So, I’m on the hunt for some quality uke plans as a starting point, then going to look into what it would take to create a production line for quick turnaround.

June 10, 2010

A lot of time this week has been spent on the building of a router table.  I have a router table that sat in my garage (the room for all my power tools) and was made of MDF which sat directly under the largest leak in the garage.  Needless to say, there are several leaks in my garage (circa 1910, cracked concrete, mostly below ground level).  All sorts of effort has been made to stop the leaks, but none successfully.  I’ve resigned myself to draping plastic garbage bags over all my power tools.  The MDF router table was unusable as it bulged from all the absorbed water over the past year.  I used it as a template and constructed a new one out of 3/4″ birch ply finished with lacquer.

I’ve been aware for some time that a router table with certain jigs is used quite a bit in luthier’s shops.  The first use is to radius bracing.  By building a jig that holds the brace blanks and has interchangeable radius templates, one can quickly and accurately radius braces and tonebars.  I’ve designed the jig, but haven’t constructed as of yet.  My design will allow for any width of brace and any radius that I have a template for (right now I have 40, 28, 20, 15, and 12).  I use 28 for the top and 15 for the back on my current guitar models.

I’ll post a few pics of the router table and jig once complete.

May 19, 2010

I completed the fret dress on the Rickenbacker bass.  It cleaned up real nice.  The frets were pitted in several positions from the 3rd up through the 9th frets.  I was able to dress down the frets leaving only one small deviation.  These frets are now down as far as they should go before a refret.

After filing the frets, the fretboard is protected with tape.  Each fret is then sanded and buffed.

The nut was removed prior to filing.  The nut is glued (lightly) back in place after the frets have been polished.  New strings were strung, took it for a test drive, and it’s a fine result.

May 17, 2010

Tom donated a semi-operational espresso machine which produces steam but no espresso.  I rigged up a hose and needle and use it to free up the glued dovetail joint in the neck.

Two holes were drilled at the 14th fret into the cavity where (hopefully) the dovetail joint resides.  It’s a bit of a crap shoot not knowing the width of the dovetail, but as luck would have it, I drilled into the cavity first time through.

It took quite some time to steam this sucker loose, as the previous neck reset was overglued (neck heel to body, bad jujus).  Some damage was done to the neck heel and the sides, but cleanup and fill will mask the damage.

The previous neck reset added extra wedges underneath the fretboard moving it farther away from the body, and a whole lot of shims.

I chiselled out all the excess shims and wedge under the fretboard and glued on two new shims, a bit oversized, but ready to be shaved down until a fine fit is achieved.

May 13, 2010

I’m doing this repair for a colleague who bought it on eBay.  Seller claimed it was “only a finish crack”.  Right.  The guitar obviously fell face first and the neck blunt forced the body into two cracks from the neck joint down through the body about two inches.  I’ll need to remove the neck, clean up the cracked finish, then glue and clamp the cracks.

So first, remove the neck.  Simple, 4 screws released, then neck pops out.

Neck has a tech’s signature and date of 3.20.03.

The cracks start at each side of the neck well and go down the back about two inches.

I applied CA glue to the back cracks, turned over then flooded the neck well with CA glue in the corners, then clamped.

While this was drying, I removed the bridge pickup to fix a loose adjusting screw.  The screw which adjusts the height of the pickup became unseated, so it just needed to be reattached.

Kristina is either the tech who installed the pickup, or the previous owner’s girlfriend wanted to mark his guitar.

Next, fill the cracked lacquer, sand, polish, then bolt the neck back on.