fret saw work in progress

[stingray_65]

It all started out with a saw blade. I was helping a friend clean up his  shop when I found this THIN blade. He said it was for his old Milwakee cordless trim saw that had gave up the ghost. By the end of the day I had it in my car and 4 blades, 2 still in the pack.

I started picking up odd parts I thought might be useful, The scrap bin in an automotive factory is great pickins for a guy like me.

Last week I decided to make a few mods to my CNC mill and I'm waiting on a new Z axis lead screw to come back from the machine shop, so I had to do something....

I started out with a pile of pallets my land lord has piled up to be cut into fire wood. After cutting apart about 20 pallets I had enough good oak to build a suitable steady table. The legs are 2 3/4" x 3 1/4" x 32", the apron is 2 1/2" x 3" and the feet are 2 3/4" x 3 1/2 Add one 3' x 4' table top found by the curb on trash day and I had a decent bench to mount it all on.

I modified the saw, divorced the battery holder / handle and fixed a broken wire going to the brush holder and BAM! I got a cute little saw that cuts a .024" wide slot, perfect for medium jumbo frets!

You can also see one of the linear slide bearings all tore down and  cleaned up on the table. 2 are needed to give the stage enough support

[stingray_65]

Next is the "heart" of the saw. 2 guided pneumatic actuators minus the old wore out cylinders made for nice rails for my Z and Y axis'.

A piece of scrap extrusion, an old bracket make a neat adjustable datum for a digital gage. a short length of 2 lead acme screw, cheap aluminum nut and a handle off an old metric chemical pump and my Z axis is adjustable, .200" per turn of the handle makes for quick traversing. A set screw with a handle stops all movement up and down.

I wanted to be able to rip and cross cut with the saw. so I needed to be able to lock the Y axis too. a collar clamp screwed to the body didn't work. too tight and the collar clamp wouldn't release, too loose and the rod had too much play. A big washer and a small die spring held the clamp just right.

[G._Hoffman]

I'm afraid .024" could lead to some problems for you, depending on the fret wire you are using.  For just about everything, we aim for a .022" slot, and .024" is just to big.  I do use a .024" slot for the Stainless steel wire I use, which has less to do with the size of the tang than the hardness of the stainless steel.

HERE is how we've been doing it for the last 35 years or so.  The machine was made for us by a crazy machinist in Wisconsin, and then rebuilt so it would work by a less crazy machinist here in Minneapolis.  The blades we use are called "Screw Slitting" blades, and they come in very precisely graded sizes, though they are usually about .001-.002" undersized (which is fine with me!)  The only problem with them is they have no "set to the teath, so they tend to stick and burn a lot.  Still, with a fresh blade you can make quite a few very fine fingerboards.


Gabriel

[stingray_65]

Here it is assembled, all that is needed is a mount for the saw. I'm waiting for the CNC to get back together before I build that, I need to have a bit of precision That I wouldn't be comfortable doing with simple layout and a drill press.

I mounted a cheap laminate router on the Y so I could surface the stage. I have +- .002" flatness with a few dips of -.005 to -.007 here and there, but no humps, not too bad for a particle board table.

The premise of operation goes like this.
1 Mount a thickness planed  finger board onto the stage with 2 sided tape. orient it fret side down, truss rode side up.
2 rotate the saw head to 90 degs. Rip both sides to parallel. move  teh saw to the aproximate midpoint  and lower the saw to cut a shallow  reference line the lenght of the finger board. This will be centerline reference.
3 flip the board and remount it to the stage aligning one of the trued edges to the fence. and rotate the saw head back to cross cut.
4 align the saw with the nut end of the board, lower the Z axis till the blade kisses off the top. raise the datum to the indicator  and set the indicator to 0.0000". Lock the Z and X axis'.
5 mount the scale template to the bench top with double stick tape. make sure the  x axis locating pin hits the firat and last hole in the template.
6 align the locating pin to the first hole in the template and secure the locating pin bracket to the stage.
7 The first hole in the template will be the end of the finger board. lower the blade and cut off. The next hole in the template is a slot. this is the nut width. lower the saw watching the indicator and set the nut depth. cut a series of kerfs in the finger board the lengnt of the slot.
8 the rest of the holes will be the fret slots. lower the saw again watching the indicator. lock the Z axis when you reach your desired depth. cut the fret slots, moving the pin in the template.
9 The last hole in the template is  the final length of the fretbord.  Cut all teh way through.

[stingray_65]

I'm afraid .024" could lead to some problems for you, depending on the fret wire you are using.  For just about everything, we aim for a .022" slot, and .024" is just to big.  I do use a .024" slot for the Stainless steel wire I use, which has less to do with the size of the tang than the hardness of the stainless steel.

HERE is how we've been doing it for the last 35 years or so.  The machine was made for us by a crazy machinist in Wisconsin, and then rebuilt so it would work by a less crazy machinist here in Minneapolis.  The blades we use are called "Screw Slitting" blades, and they come in very precisely graded sizes, though they are usually about .001-.002" undersized (which is fine with me!)  The only problem with them is they have no "set to the teath, so they tend to stick and burn a lot.  Still, with a fresh blade you can make quite a few very fine fingerboards.


Gabriel

Thanks Gabriel!
That's great info!
When I get the saw motor mounted, I'll cut a few slots with each blade and rework the offsets on the teeth to get the kerf down to .022".

OH!
That saw of yours is AWSOME!
That cast iron monster looks like it would run true for another 35 yrs with just a little preventitive maintenance.
I've got a few vacuum generators so I might borrow that idea for a hold down table.

[G._Hoffman]

I've got a few vacuum generators so I might borrow that idea for a hold down table.

The vacuum is good, but you have to be pretty cautions about relying on them.  If you get everything tweaked just right, they are great, but they can at times be pretty challenging.


Gabriel