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Circular Saw Table for Fret Slot Cutting  

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darrenking
(@darrenking)
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23/10/2019 1:23 pm  

Having been inspired by seeing Mark's modified fret slot cutting table saw I am going to have a go at building my own. Miguel at my favorite saw blade supplier (NLS - North London Saw) has found me a solid tungsten slotting blade with the requisite 0.6mm kerf but it is only 125mm in diameter (same price as the StewMac HSS blade). Rather than try to modify an existing 8" table saw to take it I think it may be easier (not necessarily cheaper) to build one from scratch as I can keep it really nice and small and design it to sit on a bench when being used and in a cupboard when it's not. I've got a 500w motor (should be plenty for 0.6mm cut) with full torque speed control which does about 2500rpm max so I'll gear it up a little to give about 4000rpm at the top end. For the sliding table I've got some 40mm Igus Drylin guide rail and slides and these offer really accurate motion for a fraction of the price of ball bearing rails and slides. The rest of the construction will be either in birch ply or 12mm solid laminate if I've got some pieces big enough.

I've also attached a picture of the spindle and motor from the last saw table that I built so I'm hoping that this one is going to seem pretty straight forward in comparison!

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Screen Shot 2019 10 23 at 09.28.09
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darrenking
(@darrenking)
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24/10/2019 12:55 pm  

The question is how adjustable does it need to be for depth of cut? How often do you need to cut different depths of fret slot or can it pretty much be set up permanently with a fixed cut depth? The fewer things that move the more stable it will be and the more accurate the cuts so I don't want to complicate the construction any more than is necessary.

I should add that I am unlikely to make a bass guitar any time soon.


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mark bailey
(@markbailey)
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04/11/2019 12:57 pm  

Hey @darrenking - !

My fretslotter is only adjusted occasionaly for Ukes - 

For guitars I've set it to cut about 4.5mm deep

I cut the slots while the board is flat

After the radius is created the slots end up 'perfect' depth for the frets (sometimes need to adjust with a hand saw)

Ideally the slot should end up 1o-20% deeper than the fret tang - the small gap underneath is filled usually with superglue...

Good luck - hope it works!

p.s. that 'multi bladed' monster looks terrifying!

FYI: For a while at 'The Factory' we used a similar spindle of 26 blades to cut 24 frets and both ends of the fretboard at once! It was pretty good until the blades got dull and then was too expensive to replace all the blades - we ended up using one blade just like I still do today...

Measure twice, cut once...


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darrenking
(@darrenking)
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04/11/2019 2:23 pm  

Hi Mark,

Thanks for the feedback and that makes everything a lot simpler. If I ever make a uke I can just take a bit more off the fretboard when I machine the radius to get the slot depth correct. Of course, cutting all the slots at once sounds like a nice idea until you want to make an instrument with a different scale length or include a zero fret. Oh that and the 26 x £1xx + vat for each blade!

The multiblade 'monster' actually performs the dullest job in the world cutting up sheets of 54mm thick polystyrene into 30mm slices but the blades were less than £20 each so not so much of a big deal investment wise and unlikely ever to need sharpening!

Regards

Darren


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darrenking
(@darrenking)
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06/11/2019 12:02 am  

I now have all the externally sourced bits for the fret slot saw other than the main shaft which I am having made in the next week or two. In the past I have always sent the relevant components to my local engineering company to make sure all the parts actually fit. There isn’t gong to be a lot of wiggle fit with the centre bore of a solid carbide blade. Hopefully by the time I get the shaft back I will have a free weekend to make up the table  components and assemble everything.

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TMHTpOdsQAyhxGmPFNUxqQ

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darrenking
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21/01/2020 2:28 pm  

Hi there and Happy new year to one and all! It already seems like a long time ago!

Now, how is this for frustrating? I  have just had a delivery from my favourite engineering company containing the machined shaft and bored out pulleys for my fret slot cutting saw table so, once I've finalised the design of the bed, and machined it, all the parts are ready to be put together. The only fly in the vaseline being that I am moving house tomorrow and so the chance of me finding a free weekend in the next few weeks is pretty slim as, I am assured, it is equally important to unpack all the boxes as well as having packed them in the first place! Hey ho!

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Bill Flude
(@frocesterbill)
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21/01/2020 4:30 pm  

Bad luck or bad planning......

Make sure that the workshop boxes go onto the lorry first that way they will be last out at the other end and most accessible.....

Measure once........
Measure again.........
Sod it - make tea!


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darrenking
(@darrenking)
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09/06/2020 12:28 pm  

A quick update on fret slot cutting saw table. I mounted the motor and splindle on some scrap MDF to check positions and ran it for a few minutes but the bearings were getting VERY hot very quickly. I checked their spec and whereas the spindle needs to be spinning at 9000rpm the bearings are only rated up to 4500rpm. Now, I always believe that there will be some tolerance built into manufacturers specification it is unlikely to be 100%! So, new SKF high speed pillow bearings have been ordered rated at 9500rpm. Happy days.

Looks like the petite bouche fretboard is being cut by hand after all!

Darren

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Bill Flude
(@frocesterbill)
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09/06/2020 1:43 pm  

You can use the old bearings in your pickup winder ? 

Measure once........
Measure again.........
Sod it - make tea!


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Petersoyanov
(@petersoyanov)
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28/08/2020 4:42 pm  

That multi blade saw looks freaky @darrenking. I have a normal circular saw rather on the cheaper side. I've been looking for solutions of making a sled for it and also for suitable blades that will fit the radius. (have no clue what the radius is) I just bought it and left it in the garage. I will get it done at some point... 

Don't grow up! It's a trap!


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