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View Full Version : July 4th was Arbor Day (not O.T.)



Frank Ford
07-05-2007, 04:05 PM
Well, for me it was. I finally got to make the slitting saw arbor I've wanted for some time. I have one of those regular R8 ones, but often enough I wished for a longer shaft for better clearance from the quill or spindle. And, while I was at it, I thought I'd make the end fitting as slim as possible - it's about a tenth of an inch thick:

http://www.frets.com/ForumPix/r8sawarbor02.jpg

This was my first R8 arbor, and it proved to be a challenging holiday project. I made the arbor both as an excercise in learning (I need a lot of that) and because I wanted the entire thing to be integral to minimize runout:

http://www.frets.com/ForumPix/r8sawarbor03.jpg

I figured my best shot at really getting the thing to run true was to turn the last few thousandths off the business end right in place on the mill, so I just grabbed a lathe tool holder, gripped it in the mill vise, and went at it:

http://www.frets.com/ForumPix/r8sawarbor01.jpg

Cheers,

Frank Ford
FRETS.COM (http://www.frets.com)
Gryphon Stringed Instruments (http://www.gryphonstrings.com)
My Home Shop Pages (http://www.frets.com/FRETSPages/Machining/index.html)

miker
07-05-2007, 06:22 PM
Nice job Frank. I take it that the keyway on the saw is not used and friction from the clamping is sufficient. Might slip a little in case of an accidental jam?

Taking the final cut on the machine on which it is to be used is probably a very good practice and one I will rememeber.

Thanks for sharing.

Regards

DICKEYBIRD
07-05-2007, 06:32 PM
Looks great Frank! How much does your saw blade run out with it clamped up and ready for bid'ness?

I made myself recently (another thread around here some place) and got the arbor to run very true in an R-8 collet in the mill but the darned blade itself had over .015" runout. Just curious if your saw runs true.

Frank Ford
07-06-2007, 12:00 AM
miker -

I was afraid you'd notice. I originally planned to use a key, but then I managed to choose a pretty skinny rod to make this thing, and I was running out of diameter fast. That, and my previous saw arbor has no key so it tends to tighten as it runs. It tightens so solidly that I've bent a couple of Allen wrenches on the weenie little flathead screw trying to undo it. So, I went with a bit fat cap screw - 3/8 NF.

dickybird -

Runout looks really good, for me at least. I had a new "Globus" 1/16" thick blade and set it up, and dealing with the bouncing needle thing, I got within a thousandth (+-) runout. All except for one tooth, which, on inspection, appears to be where I might have dropped the blade. Dropping stuff is one of my strong points. . .

Cheers,

Frank Ford
FRETS.COM (http://www.frets.com)
Gryphon Stringed Instruments (http://www.gryphonstrings.com)
My Home Shop Pages (http://www.frets.com/FRETSPages/Machining/index.html)

Mcgyver
07-06-2007, 08:02 AM
as with all our work Frank, nice job. I'd been told with the thin slitting saws to use them without a key and you've a fighting chance if it grabs (I used to say when it grabs, but I've become so good at feed the devils super slow, that sometimes I've think I'm going backward)

kevindsingleton
07-06-2007, 10:55 AM
Very well done! This is a project I'm working on, right now, so I appreciate you sharing. Can we get a picture of the end of the arbor, and the other side of the cap?

Thanks!

Frank Ford
07-06-2007, 12:57 PM
Here's a better shot of that end:

http://www.frets.com/ForumPix/r8sawarbor05.jpg

The end cap has a little recess so the outer lip can come down to grip the blade.

That means I have to use spacers either above or below the blade so the assembly is essentially flush with the end of the arbor in order to allow that thin end cap to grip:

http://www.frets.com/ForumPix/r8sawarbor04.jpg

This was another "make a tool to make a tool" project, since
I'd finally sprung for a sine bar and set of gage blocks in order to set accurate angles. So I was eager to a little holder to sit on top of my compound:

http://www.frets.com/ForumPix/sinefixture04.jpg

It took a while to get it just right, because the edge of the compound isn't quite parallel to the axis of the slide movement (about .002" off in 5 inches). Once I got that corrected, I had a fixture I could easily set on the compound to hold the sine bar.

Now, to set the angle just right, I can stack up the appropriate blocks, and squish the entire assembly against my tailstock or a bar between centers to set the angle precisely as I tighten the compound:

http://www.frets.com/ForumPix/sinefixture06.jpg

I was surprised to see how well this rig worked. I didn't have to make any adjustments to get that R8 angle spot on. Like so many of my projects, I made a slew of mistakes along the way on other parts, so the entire thing is about a half inch shorter than I'd planned, and about 1/4" smaller in diameter than I'd have liked. You'd think I'd have measured the stock first, wouldn't you? Measure once, cut twice, that's me. . .

Cheers,

Frank Ford
FRETS.COM (http://www.frets.com)
Gryphon Stringed Instruments (http://www.gryphonstrings.com)
My Home Shop Pages (http://www.frets.com/FRETSPages/Machining/index.html)