Router Bit Depth of Cut Creep - One Cause Of

[charlie b]

(Gleaned from the Router Jigs and Techniques with Bernie Maas and Michael Fortune video tape Taunton Bools & Videos ISBN 0-918804-60-4)

Seating a router bit in the router collet and tightening the collet nut is pretty straight foreward. Then you?re depth of cut setting starts changing, getting deeper with each cut, especially with a dovetail bit. You clean the collet and the bit and try again, this time making sure the bit is fully seated and REALLY snug up the collet nut.

You route some more dovetails and things seem to be ok - ?til you put the parts together. The fit is close between the half pin and adjacent tail and then gets worse acrossed the parts.

Here?s what may be happening.

If the bit is inserted ?til it bottoms out, vibration while routing will cause the bottom of the hole to ?hammer? the bottom of the bit up, no matter how much you tighten the collet nut.

Solution: Seat the bit to the bottom of the hole, then raise it 1/16th and then tighten the collet nut

|| || || || NO. Bit bottomed out in hole will hammer || || itself loose in use

+====+

|| || || || YES. Bottom of bit at least 1/16th inch |+--+ | above the bottom of hole

+----+

just something to think about

charlie b

[Frank Drackman]

I think that if you read the manual with your router you have found the same instructions

[fredfighter]

I've had a terrible time maintaining depth of cut with plunge routers. If I press down hard the cut gets deeper, probably as the hammering makes the depth stop creep. If I don't press down hard the depth gets shallow, probably the hammering makes the lock slip.

I don't have that problem with fixed-base routers.

[Max]

I use rubber o-rings to keep from bottoming out the bits.

Max

[charlie b]

Manual? Routers come with manuals - when you buy them new?

You actually read the manual for each tool?

You can afford to buy a router - NEW?

You can remember where you put the manual for the new router you bought a year or two ago?

Now I'm going to have to search the shop AND the house for the manuals for each of my mallets.

charlie b

[Eugene Nine]

That is documented in the router manual, though on the craftsman router I had no matter how tight you tightened the collet the bit would work its way loose. Haven't had that problem with the PC I replaced it with.

[Frank Drackman]

No need for referring to the manuals. It is router 101 and everyone who uses a router should know it.

[Upscale]

Naturally, I guess the person buying their first router will know it too.

[Lew Hodgett]

SFWIW

After having ALL my tools stolen a few years ago, I refuse to buy used tools unless the seller can provide a legitimate bill of sale showing they actually bought the item.

Every time I buy a tool, I write the purchase date on the cover of the manual, scan the manual, put it in a plastic folder, then file the plastic folders away for reference.

Works for me.

Lew

[charlie b]

And there's the rub - the "it's common knowledge so not worth mentioning" thing. There's a great deal of "basic fundamentals" (don't you just love redundancy) that authors of books and articles assume everyone knows or is just so obvious that it doesn't warrant getting into. I've got quite a woodworking library - books and just about every magazine over the last four or five years - and with the exception of some Ian Kirby articles, there's almost nothing on the importance of stock prep and how to prep stock properly - and check to make sure it is.

When I first got into woodworking a cabinet maker friend told me "you can't make rectangles out of trapezoids or curved parts.". If all the corners aren't square and all the edges and ends aren't straight when you start making parts for the blurfle you're making . . .

The Obvious often is only obvious after someone points it out - or - you spend a lot of time analyzing what you thought would work but didn't in order to figure out why.

If the tips I post here give the impression that I think you're an idiot who needs a lot of hand holding, please realize that I write this stuff down for my own use. Once written down it's no effort at all to pass it along. Use the info, don't use the info - your call.

charlie b

[Max]

Real men don't read manuals?

Max

[bridgerfafc]

well, aside from just helping the flat out green newbies- which is a noble thing to do- there's also the thing of keeping a large body of knowledge in motion. on some levels I might be able to stand up as an advanced woodworker, but on some other levels I'm kind of struggling along trying to figure out the basics. stuff like not bottoming out the router bits is well worthwhile discussed here. hell, it's even on topic.

[charlie b]

see "Defective Router Bit? in a.b.p.w.

charlie b

[Toller]

I haven't had the problem since I replaced the Craftsman with a Bosch. Why is it that Craftsman can't seem to make a router collet?

[Enoch Root]

I had to scrounge for the "manual" for my router (a stanley #71) on the 'Net. Nuthin' in there about collet nuts, bottoming out, vibration, etc. :)

er

[Chris Friesen]

My manual doesn't have anything about bottoming out. It's a Bosch 1617 and the collet is deep enough that I think I'd have to go to a long 1/2" bit before I could bottom it out anyway.

It does say to leave a bit of room between the cutter and the collet, I assume to allow for the usual rounded transition from the shaft to the cutter.

Chris

[bremen68]

What's a manual?

[else24]

"I use rubber o-rings to keep from bottoming out the bits.

Max "

:-) I thought I'd better read the whole thread to make sure somebody else hadn't said that first. I remember reading somewhere in the woodshopdemos website that he really liked the idea especially when using matched bits for joinery cuts. Just drop a small o ring in the collet and that bit is exactly where you want it.

Someday I'm going to try that too. :-) So far I've never had any trouble with depth creep or anything else but if I ever have to do something complicated with two bits, I've got that little tip in mind.

[Max]

Been working for me ever since I bought a "good" router several years ago. :-)

Max

[noonenparticular]

When all else fails, go back and read (find?) the instructions.