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  #1  
Old 09-07-2017, 08:22 PM
capohk capohk is offline
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Default Fret Slotting Saw

Just showing off really, but some may find it interesting... I found an antique mini table saw in a local auction recently for 15 quid and thought it could be set up for doing a job I find particularly laborious. I built a prototype sled which turned out to be perfectly functional from another bit of auction junk and added the Stew Mac fret slotting circular saw blade. I don't think the open belt is going to pass any risk assessments, but it works a treat - slotting a fretboard now takes less than 5 minutes. At some point I'll add a safety cutoff switch in place of the light switch that the previous owner had installed.

Some pics...






Last edited by capohk; 09-07-2017 at 08:48 PM.
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  #2  
Old 09-08-2017, 07:51 AM
redir redir is offline
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Nice find! Yup hand sawing slots is laborious for sure.
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Old 09-08-2017, 09:50 AM
Truckjohn Truckjohn is offline
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Very cool!

I would cover up the belt.. Not only do I highly value my fingers - but a broke belt as it is now = a face full of belt... No thanks...
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Old 09-08-2017, 11:25 AM
murrmac123 murrmac123 is offline
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Well done on getting a bargain, and on making it useful for your purpose.

I am by no means a fanatic about safety guards on machines, but I have to admit I too shuddered when I saw that naked belt.
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Old 09-08-2017, 01:06 PM
Howard Klepper Howard Klepper is offline
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Not just the belt--You have no cover over the blade for when it is not under the FB.

I don't see a method for registering the cuts to a template.

Saws with two table slots make it mush easier to have a sled that has no lateral movement. I don't see how you control that tendency.

This could be a cool little dedicated machine, but IMO it needs some tweaks.
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Old 09-08-2017, 11:59 PM
capohk capohk is offline
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Thanks for the feedback - I taped the StewMac fret ruler to the top of the workpiece to show where the cuts should be made. There's a mark scribed on the sled to show the position of the saw. Attached under the sled, there's another piece of cast iron angle that runs against the edge of the table. A mahogany strip runs inside the groove on the top of the table so it has negligible lateral wobble as it slides. The weight and quality of machining on these old tools is so superior to most modern stuff, I think they are definitely worth the effort to put to use.

Regarding a cover for the belt, that is excellent advice. I'll definitely add one. I've a chainguard from a children's bike that I think will work perfectly.
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Old 09-09-2017, 07:40 AM
murrmac123 murrmac123 is offline
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Quote:
Originally Posted by Howard Klepper View Post
Saws with two table slots make it much easier to have a sled that has no lateral movement. I don't see how you control that tendency.
I think I would have to take issue with that, Howard.

Sleds with two runners are indeed useful when it comes to cutting large panels .... I have a two-runner sled for my Grizzly tablesaw which will accommodate a 26" wide panel, but I rarely need to use it these days.

As long as the walls of the miter slot are parallel, it is not difficult to construct a single-runner sled with zero wobble or play.... the knack is in building width adjustment into the (wooden) runner, rather than trying to get a dead accurate sliding fit with a non-adjustable wooden runner right from the git-go, which will of course move over time due to wear and humidity.

If you wanted to spend money, then using a high quality after-market accessory like the INCRA steel Glidelock miter slot bar would also enable you to construct a zero wobble sled.

The big advantage of using a wooden runner is that you can glue the base of the sled to the runner, which eliminates another potential source of side play, although you still need to reinforce it with screws, of course. With a steel bar you are reliant purely on the screws to give a secure fixing.
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Old 09-09-2017, 04:23 PM
printer2 printer2 is offline
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$110 for the blade?
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Old 09-09-2017, 05:02 PM
murrmac123 murrmac123 is offline
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Looking at the pic again, I cannot help but wonder why the pulley wheels are set so far away from the arbor bearings.

Seems like there is a lot of unnecessary stress which would be mitigated if the driven pulley wheel on the arbor were moved closer to the bearing, and the motor mountings moved accordingly.
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Old 09-09-2017, 10:30 PM
mirwa mirwa is offline
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Quote:
Originally Posted by capohk View Post
Just showing off really, but some may find it interesting...
Looks good, I would concur with Howard in regards to maybe upgrading it later with twin feed rails to remove any chance of getting side deflection happening on the cutting blade as you do the slot, I am sure it works fine at the momment, but improvements can always be made.

I have a dedicated overhead compound saw for doing fretboards and I still find some slight deflection happening.

You could achieve this by using some linear rails and bearing blocks, they are cheap as these days, maybe 30 bucks cost.

A reference above was made to incra jigs, I have three incra jig units, they are really good, but they too have some side deflection as they are only supported on one edge, when cutting a 20 thou wide slot, it does not take much to make it 25 thou and no longer hold a fret.

Looks good

Steve
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  #11  
Old 09-11-2017, 01:28 PM
Rudy4 Rudy4 is offline
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Cutting fret slots was perhaps the biggest PITA for me when I first started building instruments. I quickly figured out that I'd quit building if I didn't find an easy way to do it. A few saws and many years later, here's my current saw.
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  #12  
Old 09-11-2017, 03:29 PM
murrmac123 murrmac123 is offline
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Quote:
Originally Posted by Rudy4 View Post
Cutting fret slots was perhaps the biggest PITA for me when I first started building instruments. I quickly figured out that I'd quit building if I didn't find an easy way to do it. A few saws and many years later, here's my current saw"
It's not immediately obvious from the pics how you would index your fret spacing template on that set-up, Rudy. Any chance of further elucidation ?
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  #13  
Old 09-26-2017, 06:32 PM
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That's a really cool saw. Never seen one before.
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Old 09-27-2017, 07:26 PM
phavriluk phavriluk is online now
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Default indexing fret slots

My guess is that that angled piece of wood attached to the saw base lets a fingerboard with the chosen taper be presented to the saw blade so that the fret slot is perpendicular to the fingerboard centerline. Pencil marks on the fretboard would provide the indexing.

My guess.
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Old 09-27-2017, 09:21 PM
Rudy4 Rudy4 is offline
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Quote:
Originally Posted by phavriluk View Post
My guess is that that angled piece of wood attached to the saw base lets a fingerboard with the chosen taper be presented to the saw blade so that the fret slot is perpendicular to the fingerboard centerline. Pencil marks on the fretboard would provide the indexing.

My guess.
Basically correct, but the rear fence isn't really tapered on purpose, it's just cut from scrap wood that happened to be wedge-shaped. I cut the taper later and simply start with a straight side on the fretboard blank that's parallel to the centerline.

I pencil on the positions and simply line them up with the slot where the blade cuts through the rear fence.

I could set up a simple indexing system but I do different scales many times and find manually positioning the board to work just fine.
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