Has anyone else noticed that solid carbide spiral bits are the best for mortising with a router, but that you cannot get a 3/8″ bit to fit a consumer grade hand held router? The 1/4″ bit is available, with a 1/4″ shank. The 1/2″ bit is available with a 1/2″ shank. But the only 3/8″ bits I’ve found come on a 3/8″ shank. Of course routers don’t come with a 3/8″ collet, at least that I’ve seen. Is there some rule of physics that dictates that solid carbide spiral cut bits must have a cutting diameter that matches the shank size? Is it because these bits are really metal worker’s tools and they have unlimited collet selections? I can get regular strait cut 3/8″ bits that are not spiral or solid carbide, but they just don’t work as well.
Just curious –
Jimbo
Replies
Solid carbide objects are made by a sintering process and it's more economical to make straight or round pieces, and then grind to final dimension. Also you get a stronger product that way.
Thanks Rob -
I suspected there was a good reason. I still think there would be a market though for 3/8" cutters on a 1/2" shank, so maybe some manufacturer will come up with a way to do it. Some of the responses seem to indicate that Whiteside does. I'm checking that out.
Jimbo
Jimbo, I've seen ads for 1/2" to 3/8" adaptors for a 1/2" collet. Try MSC (MCS?) in Chicago. I never bought one but recall thinking "Now why would anyone ever need something like this? Now I know. Rob
Jimbo
Check with the manufacturer of your router, you may be able to order a 3/8 or 8mm (= 5/16 in) collet for your router [I know Bosch, for one, make an 8mm collet]
the other alternative is to check the industrial tooling catalogues. I'm looking at one from CMT and see what looks like a chck which, with a matching collet, will hold any shank diametre between 4 and 13mm.
Porter Cable offers a 3/8" collet for at least the 690 series routers. I got one from a Woodcraft store a couple of years ago.
Curiousity - what drove you to purchase a 3/8" collet for it ... unless it was this same issue, being able to use a 3/8" spiral cutter? I use a Freud FT2000, and I'll check into whether they make a 3/8" collet, but I doubt it.
Jimbo, my preference for a consumer grade/ pro grade hand held router would have to be the Porter Cable router. They come with two collets, one ea for 1/4 and 1/2 shanks Ive never come accross a bit that uses a different collet size than those two standards.
You are right about the spiral bit though. Ive also found that when you are doing blind dattos/ flutes in a jig, you get the cleanest cuts with a down stroke bit and a vaccum sucking out the waste from the bottom.
No burn marks or rounds at the end of the flute. If you like I can email you a picture of a 7 foot shelf mantle with the blind flutes that I made using a spiral bit- it came out awesome!
One other thing, Jimbo. You can buy spiral cutters specifically for routers in either an up stroke or down stroke. And yes, they are carbide tipped and double fluted. Far better cutting than a straight bit.
I use the straight bit for making jointer quality edges where I can't use a jointer.
Whiteside router bits come in 3/8" spiral with 1/2" shank.....Dale
You're so right Dale. I just confirmed on a website that caries the Whiteside line. Don't know how I missed that ... I even checked Carbide.com before (they cary other manufacturers) and read all catalogues I get, which is a bunch. Thanks much for the heads up. I'm ordering one now.
Jesada sell both 1/4 and 1/2 shank spiral router bits. Up and down spirals.
http://iseek.com/Projects/omnicat5/index.php?cat_id=0
All Freud 3/8" spirals (up, down and compression) are 1/2" shank.
Charles M
Freud, Inc.
Most router manufacturers that sell in other countries offer a 3/8" - 8 mm collet. It is a standard size in many parts of the world. 3/8" shanks have much more stiffness than a 1/4" shank and 1/2" are stiffer/stronger yet. A 3/8" collet can be hard to find here, the best bet is to call the manufactures service center. My Bosch one cost about $12.
Leigh Dovetail Jigs recommend the use of a 3/8" shank and collet for most of their bits.
I am afraid you havent looked very hard, I have both a CMT and Freud 3/8" solid carbide spiral bit. Both are 1/2" shank. No need for a special collet.
Brian Klare
I have a 3/8" spiral with a 1/2" shank (don't recall the manufacturer). My problem is tha cutting length is too short for some mortises.
lee valley sells adapters for a couple of bucks. they should have them on their website http://www.leevalley.com hope this helps
Andrew
woodoworker.com carries 1/2" bushings for routers that accomodate 3/8" and even metric bores. When I started there were only 3 woodworking catalogs, 25 router bits, and you either had a PM, Unisaw or a Craftsman saw. Everything else we made or winged it and it all worked out fine.
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