Why would my new carbide 1/4″ upcut spiral bit have so much difficulty compared to the two flute carbide straight bit I was using? I could barely force the 3/4″ pine stock over the bit on the router table to cut a groove, and when I did, it was slow and smoky. I know these are often used for plunge cuts, but I thought it would work fine for a groove or other edge cut. The brand is Oldham Viper. Bad bit? Bad user? Bad choice of use? Thanks, Todd
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Replies
I'm afraid if I don't reply to my own message it may get lost. Todd
Todd,
Either it's a bad bit, or (and I don't know how you could do it) you're spinning it backwards. Could you have picked up a reverse cutting bit for some kind of multi cutter machine, like a dowel or pocket cutter?
It reminds me of the time my friend was marveling to another about my woodworking skills, as I was changing saw blades. When I started cutting, making lots of smoke, I embarassingly realized I'd put the blade on backwards. If only no one was around. I ate a fair sized slice of humble pie that day.
Gary
Ha, ha. Been there, done that.
But how deep is he cutting in one go, and how powerful is the router. Slainte.Some stuff I've made.
I'm running a Craftsman 1.5 hp and cutting 3/8" deep. Maybe I should cut less? Use a shim underneath for the first cut? Todd
Todd,
You're router's running backwards. Your bit is a reverse cutting bit. Your bit is hosed. Pick one.
R
I feel like I'm running backwards, in reverse and got hosed. Todd
Yeah. A screw driver blade chucked up in a router will cut pine, fer cryin' out loud.
Strange.
R
Well I just found out my wife left me the car tonight, but not the keys, so I'm without a bit. How exactly would you go about chucking a screwdriver...? T
No need to chuck it. Just spin it between your palms. You're cuttin' pine, right? Real men don't need no stinkin' machine to cut no soft pine!
This is gettin' outta hand, man. No keys? Get a new bit tomorrow. 2 flute carbide. Good luck.
R
Not to belabor it, but the pine is just test cut. The real cut is mahogany (and it wouldn't cut that either). Todd
Yeah, we've had fun with this one.
Y'know what. I've often had better cutting with single flute cutters than dual flute.
R
1.5 HP Craftsman. Never used one, but not a notoriously puny router size like 1/2HP. 3/8" deep cut. And on a router table. I'm guessing you're using a router fence and it's a straight cut, e.g., groove or rebate? You need to be pushing from your right to your left. Are you doing this? If you are you are working with the cutter, spiral cut and all. If not, you're working against the cutter. These were all serious questions and suggestions. I'm not involved in the goofing about which is going on, but at the same time, I appreciate the humour. Slainte. Some stuff I've made.
SD, thanks for the reply. Yes, I'm running a groove with a fence and featherboards, right to left. I'll probably give up on the spiral bit for now and return it, then buy a new fluted straight bit. I'll put down a 1/4" masonite shim for the first cut, just to make things as easy on the bit as possible. A fluted straight bit worked before, I just thought the spiral would make things easier, not harder. I really don't get it, but I'm going to find a way. I also considered buying a slot cutter, but it doesn't seem to be an advantage. Todd
Todd,
I use spiral bits successfully, and especially when I for chip free grooves and edge trimming, so I wouldn't give up on them until you know the cause of your current problem. I think it must be a faulty bit. If you're router savvy enough to use a bit with straight flutes, then I don't think it's your technique or that the spiral bit isn't tight in the collet.
Gary
Not running it backwards. Shaped similar to a brad point drill bit. Labeled as an up cut spiral. Just tried it again after breaking my cheapo two flute carbide. This time, the spiral wouldn't finish the cut in the mahogany, no matter how hard I tried to push it through. Although it doesn't sound like it's bogging down, I wonder if my 1-1/2 hp Craftsman router isn't powerful enough. Todd
Hi Toddhunter...I'll chime in..with no serious help here...
I use a PC 1.5 HP router in a table.
Just bought three ($5 each..not to GLOAT) spiral upcut bits on e-bay.....and they're cutting like butter..and I'm cutting deep mortises in White Oak.
We can all agree that something's off here...is the bit sharp? Is it possible that the collet is dirty or out-of-round (or the bit??) and the bit is somehow spinning in the collet when you try to cut?
Do you get no cuts, bad/sloppy/ragged cuts? Does the router seem to bog down when you try to rout?
What would happen if you took the bit back and got a replacement and tried it..maybe it's just the one bit....
Please keep us in the loop...a real mystery here.
lp
Larry, the router doesn't seem to bog down, though I wonder if the fact that I broke a two fluted straight bit 34" in on the mahogany piece is some evidence of a problem with the router (or me). I can't tell if there is a problem with the collet. The effect is similar to trying to get your drill bit to widen a hole. A reluctance to cut, then burn. I was able to force about a 1/2" cut on the mahog with great effort. The cut was clean, not ragged. On the pine, I cut about 12" with great effort and a lot of smoke. Again, fairly clean cut, straight. Todd
I'd have to say it was the bit. All burned up and all you will probably have a hard time sending it back. The only other thing could be runout in the collet/shaft assy of the router. If your stock shape permits it a slotting cutter is much more eficient for this type of cut.
PS: about those car keys.....:_)Scott
Scott's Sharpening Service
Glendale, Az.
I hesitate to enter this discussion.However,FWIW
the bit may be clogged with shavings. In which case, the bit will spin and heat up ,and,since there are no exposed edges to cut,it will just heat up and smoke like the devil. ¬¬¬¬¬¬¬¬¬PAT¬¬¬¬¬¬¬¬¬
Well I've purchased a cmt up cut spiral (contrary to my stated intention of going back to a two flute), and now we'll see. Thanks for the input so far. Todd
It definitely sounds like the chips are getting trapped in the grooves and not clearing. Here's why this may be happening: The upcut spiral is designed to pull the chips up and out of the groove when you're using the router hand-held. When you invert the router and fasten it to the table, do you have a fairly small diameter hole in the table insert through which the bit protrudes? If so, the chips may be be collecting between the workpiece and the table insert, not having enough room to drop through the hole past the bit. If your router table insert does have a small hole, you might want to try a larger hole--say, 2 inches--and see what happens. Nick
Well, it looks like it was the bit. What a difference! The CMT bit flowed like butter, no burn, no chatter. If I find my digital camera, maybe I'll show the test pine piece with two cuts, one brown, the other clean. To minimize future problems, I also set down an 1/8 inch shim of plexiglas to permit two cuts to reach full depth. As for chip build up, I don't think that was happening with the first spiral, but it may have contributed to the broken 2 flute. Thanks for the support everyone. It does help in getting past these obstacles. Finally, I was skeptical that the bit was bad. How often does that happen? But I've also had a bad circular saw blade in the past year, so now I may be more inclined to blame the equipment and not myself. Enjoy the world series, Todd
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