Up or Down spiral?

[handi]

Carol,

I've started this new thread to avoid "Highjacking" the original thread.

First of all, let me state that my preference for downshears extends only to shallow grooves and dados. Anything deeper than 1/2 demands an upshear.

Chip evacuation is a non issue in anything less than 1/2" deep. Run an upshear and a downshear side by side in shallow grooves and there is no more waste left behind in the downshear slot than the upshear.

I've been using spiral bits for more than 7 years, since long before they were available to the general market. I was introduced to them by Ross Gobble of Onsrud. I've used them in CNCs and hand routers.

Typically, I keep an upshear on hand for mortising, a downshear for dados and grooves, and a compression for cutting through.

Heat is certainly an issue as you state, but again, my experience is that chip evacuation is perfectly adequate in shallow grooves.

Please understand, I post this to further the technical discussion, not to be argumentative.

Ralph

[Carol Reed]

Each to his own, Ralph. I was commenting on my experience, and my experience with them goes back as far as yours as well. [img]i/expressions/face-icon-small-smile.gif[/img]

There was another point I thought of after I had posted on the other thread. There was a time when router bits cost me nothing as manufacturers were making them available gratis. It gave me the opportunity to try out a lot of things. After a while I found that I had favorites to go to. I didn't go into great introspection as to why. I just knew that for some intangible reason I had developed favorites. Up-spirals and end mills made it to my short list. If for no other reason than I felt I now 'needed' fewer kinds of bits on hand.

I no longer have an unlimited variety of bits to choose from nor do I do as much heavy woodworking as I did, due to nerve damage from an auto accident. But I still do some. My shop has shrunk considerably as well. So what I keep in it is what I consider the best for the job. We could take this conversation to a very technical level, but it serves no real purpose on this forum.

So if anyone else is still reading and not bored silly, allow me this suggestion. Observe what you do, how often you do it, and what you used to do it. Your own experience has the most value.

Happy Holidays all.

[handi]

Carol,

I've been around just long enough to know that I don't know as much as I used to, so I always welcome the opportunity to learn from anyone of different experience.

Sorry to hear about the nerve damage, I hope that the writing and such offer you the creative outlet you've lost.

Here's my secret for today: Knowing myself fairly well, I'd probably make that groove with whatever straight bit was in the router at the time [img]i/expressions/face-icon-small-smile.gif[/img]

Ralph