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I am routing a 3/8th inch notch on the top half of an “L” shaped piece of soft wood. This means I have to raise the bit 1/2 inch out of the router table to reach and begin (with 2 passes) to route the needed 3/8th inch notch on this upper half of the “L” shape. To get the bit high enough I have to cheat the router bit 1/2 inch out of the collet leaving 1/2inch to tighten into the collet. Most tech manuals instruct to tighten the entire shank into the collet. I’m just asking is this sometimes ok in situations like this. I have carefully checked and the shank tip is deeper than the compression slots of the collet so there is no collet distortion. Help? The 1 7/8th inch over all length bit just isn’t long enough, otherwize
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Replies
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I think this is dangerous. You are actually allowing the tip of your bit to wander at the risk of carbide breakage, additionally putting stress on both collet and bearings. 1/2" of the shank in the collet is not enough and a bit taking off at 24,000 rpm is a scary thought.
fv
*b canada,Holly molly! Msr. Voignier is right, this is extremely dangerous! You could already have damaged your collet. Most bit manufacturers recommend seating the bit and then raising it 1/32. I assume this is a straight bit, if so, get a longer one.Dano
*You see b canada, you are witnessing concensus at work. No recount! Don't do it! There must be another way to make that groove. Perhaps a different bit and the piece facing differently... Perhaps another tool. Give us more details as we should be able to fix that for you.fv
*Last week I had to rout a 5/16" deep slot 1.75" wide and 15 ft long in a 6/4 honduras mahogany board, at an angle across the board. I used a 1/4 shank freud 1/2" pattern routing bit which was 1/2" shorter than what I needed (my "pattern" was 2 pcs of 1" x 3/4" mahogany, 15' long, clamped to the board and blocked 1.75" apart. I was routing between the 2 pieces of "straightedge".) I cut a 1/2" long piece of 1/4" rod, dropped it in the collet and then seated the pattern bit all the way. I routed full depth of 5/16" in one pass with no problems. It didn't work without the piece of rod because the bit kept retreating into the collet. The router was a Sears 1.25 HP.I would rout about 12" at a time, then move the appropriate blocks and clamps. Total time the router was running was about 45 min.Everything worked fine, and I didn't have to retighten or reset the bit. I think the piece of rod in the collet is the critical factor, so if you do it this way be sure your bit is firmly seated on the rod and as tight as you can make it.
*Boy, this is one cool site. Quick responce and all. I really appreciate the help. Portercable's 3/8 th straight bit is much longer than my Craftsman bit. A whole halve inch longer. Boy was I lucky. I have no doubt Rob Kelly's fix would have worked but (in this case) I was able to jump right out and get the 2 3/8 " overall to replace a 1 7/8 th Craftman. Ok I'm new to this and you quys really kept me from screwing up. Thanks.
*Mr. Kelly,Congratulations on beating the odds, and with 1/4" dia bit no less! Have you heard of the quy in Manhatten that climbed into his Caddy after spending the after noon slamming down scotches and making it home safely through rush hour?Canada, USE THE CORRECT TOOL FOR THE JOB!!!!!!!There have been hundreds of articles written regarding the design, testing, quality control, by manufactures, trade publications, even Uncle Sam. Not only are the stresses present that Msr. Voignier mentions above which are crtical, but the stresses created laterally around the shaft are enormous when you consider rpm and heat. That is why the the shaft is as long as it is. Look at your collet closley to see how it is engineered, you will see what I mean. Then refer to your owners manual and I will bet the farm that they refer to regular inspection of the collet, especially if dropped, and that if a bit requires unusual effort to remove it from the collet, to replace it (the collet). By the by, OSHA does report that shaft failures do occur. Sticking a rod in the collet to remove any verticle movement of the shaft reinforces what I've just explained, becuse unless you are plunge routing, the verticle stresses are not near as great. Mr. Kelly is one of the luckiest people I know of. I've said my piece and I am as serious as a heart attack, don't do it.Have a Merry and Safe Holiday Season.Dano
*Canada,Your posting must have come up while I was composing mine. I am truely relieved that you did the right thing. Believe me, Mr. Kelly is one very lucky dude. About ten years ago I wittnessed a shaft failue of a 1/4" dia round over bit. Haven't owned one since. As a sober foot note, this individual was not doing anything wrong and did not survive this accident.Dano
*GOOD GOD, MR. KELLY!!! WHAT WERE YOU THINKING??????A "Sears" router?!?!?!?Seriously, the only shaft failure i've ever had was 1/4" straight bit on a 1/2" shaft--three of them, two different manufacturers, two different routers. I was seriously injured to the tune of sixty bucks or so.
*Mr. Splintergroupie,You also qualify as one lucky dude. Hmmm, maybe someone ought to open a folder called LUCKY DUDES.Never had one fail on me. But there is virtually no way to predict what what an object spinning at high velocity will do when it hits something or some one. Saw a fellow take a round in the thigh and it came out of his throat...go figure.This poor kid was only rounding over the edge of a table top, bit ripped right through his femoral artery at about crotch level. Was gone in less than ten minutes. Took me awhile to feel comfrortabe whith a router. Sh-t, enough said.But hey, man, you and yours Have a Merry and Safe Holiday Season.Dano
*Dano,Yes, one can never be too observant before plunging in, so to speak.
*I once witnessed a round over bit coming loose from a cheap Ryobi router, we found it a few days later in the parking lot with most of the carbide missing from it... Nobody was hurt, but that was a good enough lesson as it stood. The right tool, the right concentration and never any chances taken, that's pretty much it. Dano is absolutely right, and canada, I'm glad you made the right choice.fv
*Here's the update on extending the router bit, taking the comments not quite in order.1. The sears router is abt 20 yrs old, and I keep it around for light duty work like roundovers. This time, the 2 Bosch 1604's were bolted into the router table and the Jointmatic, the big PC was in the mortiser and I was too lazy to switch. I had a total of 50 ft of 1-3/4" x 5/16" deep slot to rout on the bottom of cap rails for a balustrade, to receive the tops of the balusters. As I wrote before, the 1st 15ft piece went fine. This weekend I was 5 ft into the 2nd 15ft piece when there suddenly arose such a clatter that I turned off the router to see what was the matter. The bit was OK but when I ran w/o load it still sounded like it was about to blow up. I figured a bent shaft on the bit so I took it out. Looked OK, and w/o a bit the router still made explosive noises. Took the router apart, figured the bearings were shot. Wrong. There's a 22 blade fan on the armature shaft, and 5 blades were busted off and being beat around by the rest of the blades. Most likely a large splinter of wood got sucked into the fan blade and started the trouble, which then progressed quickly.I broke 5 blades off the opposite side to give it some balance, straightened the remaining blades with a pliers, reassembled it and it ran like a top. Since I didn't know how much cooling air I had left, I finished the last 35 ft of slot with one of the Bosch's. I did use the Sears afterwards to put 100 ft of 3/4" roundover on the cap rails with no problem, and the machine didn't seem to be overheating. Moral of the story? Some of the tools Sears makes are damn good, considering the price they charge and the abuse they get.2. After I lost faith in the Sears router for heavy work, I dismounted one of the Bosch's. It has a slightly more than 1/2" hole under the collet. Using the 1/4" collet and the same bit (while I had it out I sharpened it with a 320 grit diamond file) I filled the space below the bit with a 3/4" long piece of 1/2" rod I cut from the unthreaded part of a grade 2 bolt. Over the next 2 days I did the remaining 35 ft of slot. No problems at all, even though after routing the sides of the slot (using the top bearing against the wood "straightedge") the 3/4" center piece was done "freehand" with the bit grabbing and tossing around fairly large chips of mahogany. With this amount of work safely done, I don't feel this is a matter of "getting away with it". This procedure is reproducible, and I think the important lesson is that the solid grounding of the bottom of the bit shaft is a necessity which has somehow been overlooked. I did note that even if I had fully seated the bit in each router, the end of the shaft was not in contact with the bottom of the hole for the collet.I have broken or bent maybe 5 or 6 router bits in 40 years, most of which were not getting the stress this one was.Another possibility is that Freud is making a super router bit. That, I have no way of determining. Comments?
*i when there suddenly arose such a clatter that I turned off the router to see what was the matterand what to my wondering eyes did appear but a vision of roebucks all trembling in fear...
*Mr. Kelly,FWIW, router manufactures suggest the gap between bit shaft and router shaft to prevent bit from bottoming out especially during plunge routing operations.Dano
*Dono, what's wrong with the bit bottoming out? Iwasn't using a plunge router, but I started the bit on a slant/manual plunge at least 5o times. If you think about it, leaving 1/32" is meaningless, because either the bit doesn't move vertically because of a nice tight collet, and thus it makes no difference if the end of the shaft is resting on steel, OR it does move vertically and ends up bottoming anyhow. Lets hear from the engineer or force analysis types out there. My own thought is that bottoming and tightening can only make the operation safer and more secure.
*Mr. Kelly,I called Porter Cable tech suuport (I'm not an M.E.), the explaination I got was, the bottom of the bit (or "rod") resting on the bottom causes wear and the possibility of metal shavining getting sucked inside the unit. As far as using 1/2 of the bit shank in the collet, I've already commented on that.Dano
*Thanx, Dano. I don't believe PC tech support, as their answer makes no sense. Think of the interface between the bottom of the rod and the floor of the collet holder. With a tight collet, there's no movement between the 2 pieces. If there were movement , the bit would be loose and the rod would bottom anyhow. This sounds like the sort of BS response that techs give when they don't know the real answer.I think the real reason has nothing to do with the rod bottoming, but is an attempt to keep the collet from being tightened on the part of the bit that transitions from machined surface to shank, which would be a weak point.
*Rob,I am not familier with Sears or Bosch routers, but am very familier with my Porter Cable, and the end of the shaft is exposed. Your arguments make sense, but I don't think they apply to the PC Model 6902 which I use.Dano
*Some stuff on "colleting up".Cutter on the bottom of collet seat may dislodge (move) due to:1) Axial armature hammering.2) Cutter may get jammed at slight angle during tightening if resting on the bottom and will move under load.3) Heat transfer may slightly move cutter.4) Full insertion may also put the fillet (radius transition of flute to shank) at the mouth of the collet, cutter will squirm or may not be tightened at all.In any event: Don't collet the cutter on the flute fade out, center long shanks on the long axis of the collet, and keep the shank off the floor of the collet seat for most consistant results. Use at least 3/4" of shank (1/2" shanks) in collet no matter what, 5/8" min. for 1/4" shanks. Tighten collet nut to about 15 pounds with 10" wrenches for maximum security.Routers
*Ta-Da-routerman to the rescue, He's everywhere, he's everywhere!So, does this mean: Follow the recomendations of the router and bit manufactures :)
*Where they make sense.
*i am more than a novice, but have a LOT to learn, so i read some of these discussions to learn and learn. how wonderful that you all have a great sense of humor. dont know how many people remember the winged warrier from the late 60"s, but it was nice to reminded of those days.
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