MIMF

Hi.

I have read the 2012 thread on table saw fret slot cutting jigs & viewed a few schemes on You Tube.
Variety is the spice of life right?
However I need to ask a question ...
Some guys use the mitre gauge almost as is, & some build sleds.
Prresumably there is some advantage in the workpiece not having to slide directly on the table top. Is it a significant improvement? Using a sled I mean.
Also presuming well set up runners on either scheme, it is necessary to do the 5 cut squaring process, or for a fret board width around 2" is the use of a square to set the front fence suffiecient?
Thanks,
Rob.

It's not very difficult to make the sled and it is a definite advantage.

I think a sled is a good idea. There are a couple of things that I discovered while making a sled.

1. The slots on my saw are only 5/16" deep instead of the usual 3/8" , and so it was necessary to plow a dado (3/32" deep) on the underside of the sled for the 3/8" x 3/4" bar (a T-slot bar from Rocker ) This turned out to be a good thing because the bar is anchored tightly in the dado, and the extra 1/32' depth also provided relief from binding because of sawdust in the slot. By the way, I suggest using the longest bar that is practical.

2. The 5-cut method works very well, and I would use it because you'll probably find the sled useful for many purposes.

If you use the miter gauge as is most likely you will have to reverse the fret board end for end to cut a few of the slots. This will double any angular error there may be. With a well set up perfectly aligned gauge it might not matter (the error will be small), but cutting them all from the same edge should make this error negligible. Adding an auxiliary fence to the gauge might allow you to cut all the slots from the same edge of the board. Using a miter gauge has one possible advantage - you can set the angle to cut the slots in a pretapered board.
That being said, most miter gauges are not well set up, the sled can be made to fit with less slop and won't need to be fine tuned every time it is used. I use a sled.

I took the time and built a sled. I didn't buy the steel rails, I just cut some 3/4 inch strips off some scrap oak I had.
My sled sits about 1/4 inch off the surface of the table, running on the rails only. Like Bob said above, this seems to help avoid sawdust build up.

I like the sled as all I have to do is set the blade height, place the sled on the table, tape the board to the fretting template, and go. My positioning pin is always in place and there is very little, to no set up time involved.

Getting the blade parallel to the miter slots is no easy feat.

Gordon, I think that you misunderstood my post.

My sled does not float above the table surface -- it rests on it. The miter bars are recessed into the bottom side of the sled by 1/16", so that there is a 1/32" clearance between the bar and the bottom of the slot. I used aluminum miter bars because I rather that the bars wear from scrubbing, instead of the slots in the table.

A David said, parallelism between the blade and slots can be a problem, but for a cut over the distance of the width of a fingerboard (~2-4"), I doubt that the error is significant unless there is something radically wrong. If you're fussy, you could use a thinner slotting blade.

You're right Bob. I did not fully understand your post.
I see what you mean about not wanting the rails or the slots to wear.
The sled I built is quite simple. Just 2 pieces of melamine connected by the front and back "ribs", and 2 pieces of oak for the rails.
It was all squared up using a good 16 x 24 inch square.

+1 for building a sled and using the 5 cut method. If you are only making one sled, make it pretty big in both X and Y dimensions - it will be very handy for lots of tasks. Mine is around 3' wide x 2' in the cutting direction.

Robert, here's a pic of an older prototype sled (or two). It's maybe a bit more elaborate than you plan on doing, but it has a couple of features that I like. The fence can be set to from 0 to 90d, and I usually set it with a Wixey digital protractor, or a hundredths ruler after trigonomtric calculations. I have also found that the ordinary 12" orange plastic Johnson speedsquare is pretty accurate for setting a right angle.

Here's a shot of mine. Pretty simple.
If you wanted to make it larger so you could use it for other projects that would be easy.

I think it'll work fine for now. But with it riding above the table surface on the the skinny strips, I wonder if it will warp over time or when the humidity changes. I would also put some kind of 'reminder' on the sled where the blade passes through the fence - maybe a tall wooden block on top, or at least a visual indicator. Thumbs are useful things, I've found, and the original equipment installation always works better than any repair or replacement. On my sled, the knobs are usually where my hands are located, and on my current sled, the left-hand knob has been relocated a few inches away to the right.

Yes, keeping the thumbs intact definitely makes you a better player.

Most of my thoughts on the subject have already been posted, so I'll just add that using a toggle clamp or two helps with the safety issue. On my "normal" fretting jig, I've got one setup to apply pressure directly over the cut, holding the blank tightly against the sled surface. On my fanned fret sled (posted here a while back), I used two to keep the blank from rotating. The cheap ones from Harbor Freight suffice.

Other tip is using a couple blade stiffeners. Mine are the cheap ones from DeWalt, and there's still plenty of room on the arbor threading for everything to fit.

I use a home made, 5", birch ply stiffener/damper with the Stewmac blade and it helps a lot but limits my blade height to about 3/8" above the table.

Similar issue with the DeWalt stiffeners, so I just cut a slot/dado in the bottom of the sled.

Hmm, I'm thinking about the concepts of imprecision and the economy of time, i.e. that the table saw has many tasks, and the time it takes to set up a wooden jig and other associated parts. How long does it take to set the entire system up? Would a well-designed hand-powered jig that holds the fingerboard for stroking a fine-bladed handsaw be more efficient? I'd expect that if I were cutting 10-20 fingerboards at a time then the tablesaw jig would be more efficient, but if I were only cutting 1-4 fingerboards in one episode, would it be better to use an 'Arm-strong' jig?

Bob Hammond wrote:I think it'll work fine for now. But with it riding above the table surface on the the skinny strips, I wonder if it will warp over time or when the humidity changes. I would also put some kind of 'reminder' on the sled where the blade passes through the fence - maybe a tall wooden block on top, or at least a visual indicator. Thumbs are useful things, I've found, and the original equipment installation always works better than any repair or replacement. On my sled, the knobs are usually where my hands are located, and on my current sled, the left-hand knob has been relocated a few inches away to the right.

1. Humidity. I live in a quite dry climate. Every once in a long while will the humidity get above 40 or 50%. Wood is very stable here.
2. Thumb reminder/protector. Yep. Already on. The pic was taken before I put it on.

How long does it take to set the entire system up?

Bob, it takes 10 minutes to build a sled and it will outlast your career, and less than a minute to swap the blade on the table saw when you need to slot a fretboard.

Slotting a board on the TS takes me about 2 minutes and setup is probably 5 which is mostly clearing all the crap off it so I can push the fence down to the far end. The advantage of a smaller table saw is that it holds less crap.

Thanks for all the info.
Am I right in assuming that I'll need to cur the slot in the sled using a 'normal' blade since the available depth on the slotting blade is insufficient to pass through the sled bottom - about 6mm say - and then cut a slot? If I square up the fence using a normal blade what are the chances of changing to the fret slotting blade making things out of square? I ask because they're very tin.