Routering help needed: collet grip / bit slip

[dstmbgh]

I have a twenty year old Sears Craftsman router with a 1/4" collet, and I'm using a new spiral downward solid carbide bit to cut recesses and holes in a 3/4" mdf baffle. When I make test cuts in 3/4" oak veneer plywood the bit slips, extending outward, making the cuts deeper than intended. I have not yet had this happen with the mdf, but I'm worried that it will, and ruin my work. I understand what's happening: the new, sharp downward spiral bit is gripping like a drill and pulling into the hole, causing the bit to slip in the collet. I understand that a narrower 1/4" collet/shank is more susceptible to slipping. I also understand that shallower cuts and a slower speed will lessen the tendency to slip. The router is not variable speed.

Besides the above, any suggestions on how to "treat" (clean, sand, adjust, etc.) the collet and/or bit to lessen the slipping?

Thanks for all help.

David

[JonMarsh]

You might try roughening up the shank a bit with sand paper or a file to help it get a better grip. I'm guessing that you've already used a double wrench setup for tightening the collet and don't think you can get it any tighter?

Sadly, it just might be time to update that craftsman with something newer, painful though that might be at first.

[PMazz]

What Jon said. I wouldn't go near a 1/4" solid carbide bit cutting 3/4" anything. That router should only be used for light edge shaping/trimming.

[CADman_ks]

I have a twenty year old Sears Craftsman router with a 1/4" collet, and I'm using a new spiral downward solid carbide bit to cut recesses and holes in a 3/4" mdf baffle. When I make test cuts in 3/4" oak veneer plywood the bit slips, extending outward, making the cuts deeper than intended. I have not yet had this happen with the mdf, but I'm worried that it will, and ruin my work. I understand what's happening: the new, sharp downward spiral bit is gripping like a drill and pulling into the hole, causing the bit to slip in the collet. I understand that a narrower 1/4" collet/shank is more susceptible to slipping. I also understand that shallower cuts and a slower speed will lessen the tendency to slip. The router is not variable speed.

Besides the above, any suggestions on how to "treat" (clean, sand, adjust, etc.) the collet and/or bit to lessen the slipping?

Thanks for all help.

David

I have a Craftsman router about that same vintage. In that time frame, they were all the same, and I think that they only had one version, so I'm guessing that your's is just like mine.

As mine has aged, it's doing the same thing. I think that it's' just from getting old and wearing out, unfortunately.

One bad thing about those routers is that they do NOT use a double wrench setup to tighten the collet, and so you only get one wrench on it. The locking mechanism on them is kind of cheezy as well. I'm always worried that the lock is going to break if I tighten it too tight.

If getting a new router is out of the question, I would go with the suggestions of others that you go really slow, and take multiple passes, which sucks, but it allows you to sneak up on a set depth without issues...

[cjd]

The problem with ANY attempt to "roughen" the surface is that you'll also be making it smaller - the opposite of what you need to do.

If you are unable to try a replacement collet, I would not use that router for ANY work of this nature. A bit that doesn't stay in place is a risk it's just worth taking - if it were to actually wander completely loose who knows where it would go.

[Lurkalot]

If available, purchase a new collet. Do not take an abrasive to the shank of the router bit, and take shallow cuts to reduce the load on the router bit.

[Ray_D]

I agree

If available, purchase a new collet. Do not take an abrasive to the shank of the router bit, and take shallow cuts to reduce the load on the router bit.

I use a 1/4 inch solid carbide spiral upcut bit frequently to make templates and clearance holes. It just needs to be tightened properly and only cut 1/4 inch depths at a time.

I also endorse using OD templates for cutting driver recesses. I wait and cut them just before the final finish coats. That leaves more surface area on the baffle for sanding stability. This is the bit I use (5/8"):

http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_dado.html

Ray

[JonP]

What they all said...

I've used the carbide spiral bits, nice sharp cuts... And, Ive had problems. Some excessive vibration, and have had a couple break, but not catastrophacally... Seemed to be partly due to a worn collet (got a new one helped but did not cure) as well as the lower bearing going out. Something I seemed to notice, the carbide has a lot of expansion compared to steel, ifyuwork it hard, its a lotof stress on the bit. All the more reason not to go big on the cuts, slower and shallow will keep the heat down.

[dstmbgh]

One bad thing about those routers is that they do NOT use a double wrench setup to tighten the collet, and so you only get one wrench on it. The locking mechanism on them is kind of cheezy as well. I'm always worried that the lock is going to break if I tighten it too tight.

Yes, this describes my router. While it's older, it has not had heavy use. It could be 16 years since it was last used, and I've never made an attempt to clean or lubricate the collet. I'll try the suggestions, and make sure that I make my own safety the first priority. I'm trying to make use of what I have, as I hardly do enough woodworking to warrant a new 1/2" collet router, and I've just purchased a half-dozen decent mcls 1/4" shank bits specifically for the couple of speaker projects I'm currently building.

Thanks for all the helpful suggestions.

[CADman_ks]

Yes, this describes my router. While it's older, it has not had heavy use. It could be 16 years since it was last used, and I've never made an attempt to clean or lubricate the collet. I'll try the suggestions, and make sure that I make my own safety the first priority. ...

I've also noticed with my Craftsman when I do use it, that I need to put the shank of the bit in as far as it will go. I don't "need" to do that with my Dewalt but typically do. Sometimes, though, you'll run into a situation where you have to leave the bit stick out of the collet a little bit further to get deeper, or whatever. That just doesn't work with my Craftsman. That's when it slips.

You probably already know this, but we didn't mention this specifically...

Good luck!!

[Ray_D]

Useful link

Yes, this describes my router. While it's older, it has not had heavy use. It could be 16 years since it was last used, and I've never made an attempt to clean or lubricate the collet. I'll try the suggestions, and make sure that I make my own safety the first priority. I'm trying to make use of what I have, as I hardly do enough woodworking to warrant a new 1/2" collet router, and I've just purchased a half-dozen decent mcls 1/4" shank bits specifically for the couple of speaker projects I'm currently building.

Thanks for all the helpful suggestions.

Your collet and bit should be clean. Do not lubricate the gripping surfaces.

To properly tighten he collet, lay the router on its side with the bit facing away from you and so that the wrench near the motor is resting on the bench, on the left. The wrench tightening the collet should be a little above the bench. This allows you to use weight rather than strength to tighten it. To loosen, move the wrenches to the other side.

Here is a link that may be useful: http://www.mlcswoodworking.com/shops...TM25spiral.pdf

Regards

Ray

[CADman_ks]

...

To properly tighten he collet, lay the router on its side with the bit facing away from you and so that the wrench near the motor is resting on the bench, on the left. The wrench tightening the collet should be a little above the bench. This allows you to use weight rather than strength to tighten it. To loosen, move the wrenches to the other side.

...

Ray, that's great information!

Unfortunately, the OP's router does not have the capability to use two wrenches. There is a spindle lock that engages the shaft, and then you use a wrench only on the collet. A lot of routers are this way, but this Craftsman router has the LOCK on the opposite end of the router, so the locking mechanism is about 10" away from the collet.

When you tighten this thing, it often feels like the lock could break. It's just really winky. It definitely is not the worlds greatest design by any means...

[Face]

It's time for a new router, why take a chance?

[Hank]

Yes - buy the DeWalt DW621 with built-in dust collection on this page:

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dtools&field-keywords=DW621

[CADman_ks]

Yes - buy the DeWalt DW621 with built-in dust collection on this page:
http://www.amazon.com/s/ref=nb_sb_no...keywords=DW621

I understand that money can be tight at times, so I wasn't going to suggest going the new router route.

But, if you are so inclined to go this route, this IS the router to have in my opinion. This router has a "double" locking collet. You can't feel it when you're tightening the bit, but when you loosen the bit, you have to loosen the collet nut to a certain point, and then it gets tight again, and you have to break the second lock free to get your bit out. (I didn't know that it had this "feature" when I bought mine, and I just about took it back to get my router bit out, and to get a new one! Thank goodness I read the instructions!!!)

Take that with a grain of salt, though, because I bleed Black and Yellow...

[Hdale85]

Did they start producing the DW621 again?

[dstmbgh]

Okay, so...tonight before I began working I cleaned the inside of the collet well with some emery cloth and mineral spirits, being sure any residue was wiped clean afterwards. I also cleaned the threads, both on the collet and the collet nut. Per one poster who said that his Craftsman router like mine required that he make sure the bit was seated all the way in the collet otherwise it would slip (contrary to general practice), I tried this, tightening the collet nut as much as was possible (remember, my router does not have a double nut tightening setup). I also made sure the bit shaft was clean. Proceeding only 1/8" at a time, I completed all driver cutout holes with no problems with the bit slipping.

Previously the bit slipped mostly with oak veneered plywood and with cuts in excess of 1/8". Maybe it still would under those conditions, but that's neither here nor there, as I won't do that again. The good news is I am making progress now without problems.

Thanks for all your help, guys.

David

[CADman_ks]

Did they start producing the DW621 again?

They still have it listed as a current model on their website...

[CADman_ks]

... The good news is I am making progress now without problems.
...

That's the best news of all right there!!!

[Hdale85]

Hmm they discontinued it at one point I believe. Cause it was really hard to find back when I got my first one.

[Renron]

To the OP. I am a professional Carpenter not bragging, just background. I also had that Craftsman router with the same problem. Upon extreme close inspection of the collet it had a micro fracture I could not see with an unmagnified eye. I tossed the unit in a drawer hoping to later make use of the motor in another project. I finally tossed it out and bought a very clean slightly used Bosch plunge router on Fleabay. Stripped it down and cleaned everything. Been working perfectly ever since. Don't look back, move on to something better and your woodworking skills will increase dramatically.
Ron

[Dave Bullet]

I'm late to the party - but a nail punch on the shank. Seriously. In a few places the "dimple spread" gives the collet something to bite onto. Don't be too aggressive or you won't be able to slide the bit in! Do a few at random places around the shaft with low impact. you'll feel resistance inserting the bit, don't overdo it! but it will grip well