Fret slotting jig, Digital

[auscab]

I saw some of these a while back for sale in the US, and almost bought one , better quality than this one and approximately $300 delivered,
Thought I would make a jig for slotting templates for fret boards ,or cutting them direct
A few days back spotted this one on eBay $ 49 inc postage from SA , they sell them at 1 meter as well.
So I've started a DRO slotting jig
Any one used one of these before ?

here is the eBay link ,

http://www.ebay.com.au/itm/270800068994 ... 1423.l2649

[simso]

Ive used those dro's and fitted them to drills and lathes, but never for a slotting jig, interesting idea

[bawdy]

You will have to excuse my ignorance here, but presumably this is like an electronic dial gauge, only longer?

I did not know such a thing existed!! Gunna have to get me one, brilliant!!

Thanks for post, love to see final gig and how it works out.

Paul.

[auscab]

I'm trying the KISS approach here [ Keep it simple stupid ]
two fixed fences and one in between that slides,with a screw through to a knob at the back to clamp it.

Steve , I,m glad to hear someone has used a DRO before , do you know what the set button set's ?
The rest of it seems straight forward.

Paul, your first post , welcome to this part of where ever we are ? Bobs office in a box under his desk.

" but presumably this is like an electronic dial gauge, only longer? " Yes that's it

The better quality ones that I spoke of before
are here

http://www.shars.com/files/products/cat ... Page54.pdf

Rob

or this is there home page

http://www.shars.com/

the 40" one was quoted at $344 delivered, I have a 2oo mm one of these that bought to fit to my thicknesser years back , a lot better quality .

[simso]

The set button merely resets the zero reference point. Example move the dro sensor down the shaft and then hit zero, everything is now measured from that point

[simso]

Its actually not a bad idea, they are getting cheap enough, to actually fit them to tablesaws / bandsaws etc. They run on 3 batterys from memory, 2 double a's in the display unit and a 3v mini in the sensor

[Daniel_M]

I like it alot Rob! great idea

[J.F. Custom]

I'd just like to add a voice of caution to the mix here.

These DRO's are manufactured in the same way as digital verniers/calipers - the mechanisms of which can slip. By this I mean that after frequent movements of the sliding part back and forth, you may find when you return to zero, it is no longer zero.

Having not been designed for this style of use, I'm not sure of what repeatable accuracy they will guarantee/claim to achieve. Used mounted on something like a thicknesser, they perform fine - not likely to need pinpoint repeatable three decimal accuracy for such a job.

They are better these days than they used to be but quality still varies so I would just suggest to use with care for your intended purpose as accuracy is everything on a fretboard. The same could be said and applied to other methods of fret slotting too so this does not rule it out; but it pays to consider that potential now than when you wonder why a note is playing out of tune on the finished instrument! If for example it "skipped" a registration whilst measuring to the fourth fret and you were in fact 0.7mm out; all frets thereafter will also be at least 0.7mm out.

Anyway, nice idea if the technology is up to it. Good luck and erm, measure twice, cut once as they say.

Jeremy.

[charangohabsburg]

Rob, this approach makes my mind wandering (and wondering). There are new possibilities! Great idea.

Good luck and erm, measure twice, cut once as they say.

Now it's already the third time I cut, and it's still short!

[Nick]

I'd just like to add a voice of caution to the mix here.

These DRO's are manufactured in the same way as digital verniers/calipers - the mechanisms of which can slip. By this I mean that after frequent movements of the sliding part back and forth, you may find when you return to zero, it is no longer zero.

Having not been designed for this style of use, I'm not sure of what repeatable accuracy they will guarantee/claim to achieve. Used mounted on something like a thicknesser, they perform fine - not likely to need pinpoint repeatable three decimal accuracy for such a job.

They are better these days than they used to be but quality still varies so I would just suggest to use with care for your intended purpose as accuracy is everything on a fretboard. The same could be said and applied to other methods of fret slotting too so this does not rule it out; but it pays to consider that potential now than when you wonder why a note is playing out of tune on the finished instrument! If for example it "skipped" a registration whilst measuring to the fourth fret and you were in fact 0.7mm out; all frets thereafter will also be at least 0.7mm out.

Anyway, nice idea if the technology is up to it. Good luck and erm, measure twice, cut once as they say.

Jeremy.

Great caveat Jeremy! I use this technology daily and if the stationary strip gets the tiniest amount of oil or fluid on it (Quite often even a greasy/oily finger can be enough (maybe not what you would have around a fingerboard perhaps, but still...)), it can skip as you say & this is on a $200 German set of 200mm calipers not a cheaper set! I got burn't once with it when I'd first got the calipers & the job ended up in the scrap so now I slide the thing back to where 'Zero' should be & check before every measurement. Cheap insurance as far as I'm concerned!
But its a great idea Rob and a cheap,accurate approach. (got to be good if it's got Markus thinking possibilities! )

[auscab]

Thanks for all the constructive comments gents.

Steve, this unit uses two flat ,big as my thumb nail batteries that go in to the back of the pictured control box , I think the set button does zero it but possibly it's used when using the ABS, I will play and see.

Daniel, Iv'e wondered what that little emoticon is drinking, looks like Coopers Invalid Stout, " a roast meal in a pot " or schooner,even better.

Jeremy and Nick ,good advice, Ive read up a little last night on how these things work,after reading Jeremy's post.
Moisture,oil and water, Dirt ,have to kept out,I may have to put a cover on it. Got to keep batterys out of it while not in use,or they constantly drain,I think that may be on the cheaper unit's, possibly dim batterys = dodgy reading.
here is one of the links I read on how they work

http://www.biotele.com/digital_caliper.htm

Markus,thanks. 3 times still short, not on that expensive tone wood I hope

I sure know the meaning of " measure twice ,cut once " You learn it the hard ,and quick way when you pay for your own wood.
After having apprentices, and they keep getting it wrong ,it's amazing how many different ways this can be said

[charangohabsburg]

I think cheap electronic callipers would be even much more useful if they could be plugged in the socket-outlet, or at least could run on a car battery.

Thanks for the link about how these things work. I didn't know how oil affects their functionality.

Markus,thanks. 3 times still short, not on that expensive tone wood I hope

Professor Murphey says that it does not happen with cheap wood, and not with wood of which you still have a spare piece.

[auscab]

Pretty much got this finished today, after putting together and pulling apart many times,the basics of it are ,

It has two fence set ups ,the first fence is made of three lengths of Oak and has the digital read out attached, a sliding stop,three rubber{ re constituted truck tyre , and foam ex camp mattress ] sprung or pressure Teflon pads within, and a brake which is controlled by the brake knob

The fourth fence has got a brass reference strip , to be used with the templates that can now be made on the first fence set up.

I made two Oak sticks to fit the top of my table saw , then nailed with glue the ply to them,this is made to be a nice tight sliding fit , the saw blade was then bought up through the ply to give me one clean cut, and the first fence glued down square to the saw cut,the best square was to make one from a scrap of mdf to suit the size of the square up job.

Once the first one was dry,the second sliding, and third ,screwed only, were fitted , it was a rough slide so I put the three pressure pads in to keep the second sliding on the first, and a small gap [ newspaper folded four times ]between the second and third , so just the Teflon was pushing.

Then I worked out that I could use the rubber as a brake and that the pressure from this would be adjustable, it worked well ,I can apply pressure to the no 2 slide and watch the number rise slower and slower as the knob is turned, it was pretty jumpy before that with plenty of forward and back, past the number adjustments.

The center bolt had a few re incarnations with the Oxy torch, but if planned out well and not so thick a rubber disc for the brake ,it could be done with a standard screw from Bunnings

I'm going to tape the Masonite down or glue it in spots with news paper in between and bring the Stewmac blade up through it for the first fret board later this week I hope, will try a template out first.

I have tapped holes in my table saw for another jig I have , and this came in handy for a rubber stop with a oak cap and a wing nut up the back of the jig, You got to have a forward and back stop set up on one of these, very very dangerous with out one. if you made one like this and don't want to make a hole just make the ply over hang enough to screw stop blocks on the under side.

I found out that Shars sell the quality DRO's on eBay,which will make it a lot more easy to buy, I'm going to swap over to that one I think.
here it is .
http://www.ebay.com.au/itm/300553756660 ... 1423.l2649

cheers

[auscab]

I just found this link to making a cross cutting sled, it's the same steps I did for the slotting jig , I glued and nailed my guides though, but it shows a really good method [ the five cut method ] for getting the fence square, never seen that one before .

http://thewoodwhisperer.com/the-cross-cut-sled/

I just bought myself a second hand Wadkin table saw off eBay to replace the Carbatec one that the jig sits on,so will have to alter a few jigs to suit the new slots, great little 3 phase saw though. some real bargains to be had on eBay.