Machining stem flats

kbadkar · Post by **kbadkar** » Fri Feb 01, 2008 2:29 pm

I've been thinking for sometime about how to quickly and efficiently get the flats of a saddle type bit perfectly parallel and thin. I've thought about setting up some kind of jig with my router table and a fluted flushing bit (w/guide wheel) or an end mill type bit, but I haven't visualized a satisfactory solution. I keep coming back to the idea of using a milling machine. Has anyone tried using a milling machine for stem shaping? Does anyone have a shortcut procedure or machining operation for the saddle bit flats? It seems most of you guys use a 1" belt sander. I waste too much time removing material between the bit lip and saddle, since my only belt sander is 3" wide.

Nick · Post by **Nick** » Fri Feb 01, 2008 2:57 pm

I seem to recall some one using a router table and a jig for a tapered stem. I don't see why such a thing wouldn't work for a saddle bit. If I remember correctly, the jig was simply two pieces of wood clamped to either side of the stem, with the one at the tenon end being higher than the button end. Naturally, the wood on the top side of the stem would be the same height on the bottom side, to give you the same taper. One could just as easily make the jig so that it the router would cut the saddle.

Lemme see if i can't find the post.

Nick · Post by **Nick** » Fri Feb 01, 2008 3:24 pm

Well, I couldn't find the post, but here's my recollection of the jig. I've also drawn out what I presum would work for a saddle jig.

kbadkar · Post by **kbadkar** » Fri Feb 01, 2008 4:11 pm

Thanks for the idea, Nick! I'm still chewing on it. It's a similar setup to what I was visualizing. Securing the stem in the jig, repeatability, guide for parallelity(?) w/slot and other flat side, and not having to adjust router bit depth are details that I get stuck on, but must be resolveable somehow.

I'll start experimenting this weekend, IF I have time. My wife will kill me if I don't find a way to locate and remove the fetid dead rat hidden somewhere in the walls... damned priorities. If anyone has a shortcut suggestion for that, let me know. All I can think to do is randomly drill holes, determine the stinkiest one, and cut out some drywall between stud centers. Yuck.

Post by **KurtHuhn** » Fri Feb 01, 2008 6:35 pm

Nick, you might be recalling a photo that Tom Johnson had on his website. His domain expired, but through the magic of the Wayback Machine, I present to you this:

More can be found here
http://web.archive.org/web/200608190735 ... /index.htm

kbadkar · Post by **kbadkar** » Fri Feb 01, 2008 8:43 pm

Thanks for digging that up, Kurt.

Post by **KurtHuhn** » Sat Feb 02, 2008 4:15 pm

No problemo! I've actually given that setup some thought recently. It's a great way to guarantee a repeatable stem. Probably a hell of a lot cleaner than grinding, too.

JBW · Post by **JBW** » Sat Feb 02, 2008 5:43 pm

Crazy idea #54637......

Looking at the photo of the jig, I was wondering if the desired profile of the stem were extended to the outside could you shape the entire stem and not just 2 flat sides? Not sure if this is clear or even makes sense.

Thoughts??

caskwith · Post by **caskwith** » Sun Feb 03, 2008 8:26 am

JBW wrote:Crazy idea #54637......

Looking at the photo of the jig, I was wondering if the desired profile of the stem were extended to the outside could you shape the entire stem and not just 2 flat sides? Not sure if this is clear or even makes sense.
Thoughts??

I think i get what you mean, ie shaping the ends of the jig to be rounded so you could rock the stem over the cutter and curve the sides? In my head it seems as if it would work, would require a fair bit of planning and experimenting to get it right i think, but once mastered it should work pretty well.

Nick · Post by **Nick** » Mon Feb 04, 2008 9:36 am

caskwith wrote:
JBW wrote:Crazy idea #54637......

Looking at the photo of the jig, I was wondering if the desired profile of the stem were extended to the outside could you shape the entire stem and not just 2 flat sides? Not sure if this is clear or even makes sense.
Thoughts??
I think i get what you mean, ie shaping the ends of the jig to be rounded so you could rock the stem over the cutter and curve the sides? In my head it seems as if it would work, would require a fair bit of planning and experimenting to get it right i think, but once mastered it should work pretty well.

I had a the same idea. Too cool!

ASB · Post by **ASB** » Thu Mar 27, 2008 4:04 pm

JBW said

Crazy idea #54637......

Looking at the photo of the jig, I was wondering if the desired profile of the stem were extended to the outside could you shape the entire stem and not just 2 flat sides? Not sure if this is clear or even makes sense.
Thoughts??

How about if you had a bearing inside the wooden part so you could just spin the stem around slowly as opposed to having to rock the whole assembly? There could be a standard OD that you would turn the blank to to fit into the bearing with the tennon sticking out to hold and turn by.

JHowell · Post by **JHowell** » Thu Mar 27, 2008 11:40 pm

ASB wrote:JBW said
Crazy idea #54637......

Looking at the photo of the jig, I was wondering if the desired profile of the stem were extended to the outside could you shape the entire stem and not just 2 flat sides? Not sure if this is clear or even makes sense.
Thoughts??
How about if you had a bearing inside the wooden part so you could just spin the stem around slowly as opposed to having to rock the whole assembly? There could be a standard OD that you would turn the blank to to fit into the bearing with the tennon sticking out to hold and turn by.

That would just make it round (or cone-shaped) instead of a graduate radius, big radius (almost flat) at the tip and small radius at the tenon. I dunno, to me it doesn't seem to take that much time to cut a stem, this seems like a lot of setup and you'll have vulcanite dust everywhere. Heck, somebody try it.

Frank · Post by **Frank** » Fri Mar 28, 2008 3:35 am

The logistics of trying to variable radius the edges mechanically wouldn't be worth the time, effort or money. By the time you managed to Heath-Robinson a contraption that could do that, you could just as well have bought a duplicator attachment for your wood lathe.

PS: In case you're wondering what a Heath-Robinson contraption is, this should illustrate the point: http://www-uxsup.csx.cam.ac.uk/~fanf2/h ... binson.gif