Table saw crosscut sled for fret slotting

[Kevin Canney]

Hi, all --

After years of buying slotted fingerboards, I decided it's finally time to start slotting my own.

I'm ordering the StewMac table saw blade and fret scale templates, but I had a question for you guys regarding the sled.

I made a crosscutting sled for my table saw a few years ago. Using the five-cut method, I managed to make my crosscutting sled accurate to within 0.0005" over a 16" cut. That's been accurate enough for anything I do, but I have to wonder whether the fret-slotting sled requires the same level of attention.

To start, I put the crosscut sled in my miter slots, clamped my new fret-slotting sled to the crosscut sled, and attached the miter slot runners.

I assume that's probably accurate enough, since the frets will all be parallel to each other, I will have a reasonable square edge, and I always draw a centerline relative to the slots anyway.

Is that a fair assumption, or is it worth running through the five-cut method to true up the slotting sled when my new fret slotting blade arrives?

Thanks!

[Russell Vance]

Hi Kevin,

Max length of cut is going to be less than 70 mm so its probably overkill to do much more than a good square check.    I have used a Stewmac table saw blade and I have used the LMI Blades (with hefty blade stiffeners).   I prefer the LMI blades (which come in two widths for rosewood and ebony slots) and last considerably longer from experience.  Also check your tablesaw for wobble and slack - it doesn't appear for general woodworking but the close tolerances for slotting soon shows how stable yr mounting is.

Regards,

Rusty.

Rusty.

[Mark Fogleman]

It's always a good thing to get a square cut but blade and arbor mounting surface runnout will also effect the slot width. Any gradue build up on its mounting surface or runnout will cause blade wobble and widen the slot. I would give it a really good clean up and check it with a dial indicator. Work down the high side with a fine cut file until you are running flat. After this check your miter slot squareness to the blade and make adjustments to your top. 

[Kevin Canney]

Thank you, Rusty and Mark!

That's an excellent point about the short length of cut relative to squareness. I hadn't thought of that.

I'll give the saw a good cleaning and checkup.

Have a great day!

-Kevin

[Russell Vance]

Hi Kevin,

Mark's right on the money here, blade wobble is the killer in domestic table saws and the likes and so is run out - one way to tell despite your best efforts of squaring everything statically is to look at the start of the cut when a single quick pass is made.  if it has a tapered "funnel" into the main part of the thinner slot cut you have blade wobble.   If you slow cut slots or do multiple passes you will generally end up with a wider slot than advertised.  As I mentioned we use 2x 1/8th" blade stiffeners which keeps the blade  flat but loads up the arbor and bearings with extra mass which exacerbates any slack or in-balance.   Solving one problem invariably invites another problem to the party!

Regards, 

Rusty.