Jacobs Chucks

[jim_melton]

Has anybody tried (or have any thoughts on) finding a Jacobs chuck that will fit (or modifying to fit) to eliminate the need for different size collets to hold your bits?

I was thinking of finding a straight shank 1/2" Chuck that would fit the collet on the PC7518 and then using that instead.

Any comment?

Jim

[Wdyasq@yahoo.com]

Jim,

There are several problems I can see using a drill chuck in a router.

First; in a milling type operation, the cutting tool is side loaded. Few drill type (Jacobs) chucks are designed to handle sideloads.

Second; anything as heavy as drill chuck will have a high inertia and this might cause some problems.

Third; the drill type chuck would extend the length unsupported by bearings a consiterable amount. The drill chuck I just measured is 2.5" long.

Fourth; alignment and runout might become a problem.

I'm sure others could add more possible problems.

Ron

[jim_melton]

I had thought of that as well, but lately all of my cutting has been on sign foam at 10K -13K RPM. Sign foam cuts like a hot knife through butter.

I was wondering about it. I am currently using the RC Eliminator chuck and the reducer collet is a royal pain. It can be difficult to get the collet out and the metal it's made from is very soft and is easily marred by the lock. My biggest concern would be the effect of the mass on the PC7518 and the balance of the chuck.

Jim

[bwclark@Centurytel.net]

Jim,

For your OWN safety, NEVER use a drill chuck to hold a milling cutter!

Second, NEVER use a drill chuck in a router! Drilling chucks are not designed for even the slowest speed on your router. About the faster they are designed for is 3000rpm MAX!

Now, I agree, using a reducing collet increases your runout, reduces your holding force and is a pain to change. What I did was purchase a ER16M collet holder and collet sets. This is 1/2" diameter and is precision balanced to run at high speeds. It will hold anything from 1/4" to .030" and hold it tightly, accurately and is a breeze to change. The downside is they are fairly expensive--about the price of a good router motor!

If you want more information, I can take a snapshop and email it to you along with part numbers from J&L Industrial supply.

Bruce Clark
bwclark@Centurytel.net (mailto:bwclark@Centurytel.net)

[Ross Kowalski]

I recently did a 1/2 shaft for a 3/8 jacobs chuck and have been playing with it for a couple of weeks.

I did not put a dial on it, but it doesn't have any runout that matters. I have run it with only 1/4 and 1/8 bits as well as a piece of music wire, but it didn't vibrate or leave chattermarks.

I didn't run it up to full speed, but I did have it run at 16,000.

I wouldn't do production work with it, but it is nice to have arond for doing "non-standard" work.

Here i a pic of it with a piece of music wire (not spinning of course)
http://www.edu-coop.org/images/skull.jpg

[rgbrown@itexas.net]

Ross,

I suggest you read the posts above yours. Stationary, a Jacobs Chuck will be fine. Spinning one at the minimum speeds a router will run is a questionable practice to begin with. In an environment of ignorance, neglect or just forgetfulness, I believe it may result in serious injury or death.

I believe all of us at one time or another has chucked a bit 'off-center' in a Jacobs style chuck. In a hand held drill or drill press this is quickly noticed and corrected. In a router - with the potential of ~25,000RPM+, I can see the vibration shaking the machine, bending the shank and a half pound Jacobs chuck sling-shot across the shop.

Or, let's just get a phone call in the middle of changing bits and forget to take the chuck key out.......

I've never been around a half pound tool being ejected from a router. I was present when a 1/4" shank 4 wing slot cutting bit failed to get tightened up in a router. I can attest that is far more excitement than one cares to experience outside of an amusement park.

Ron Brown - rgbrown@itexas.net (mailto:rgbrown@itexas.net)

If Stupidity got us into this mess,
then why can't it get us out? - Will Rogers

[gerald_d]

Ross, please post the sddress of your shop so that we can keep a 1 mile clear radius!

Seriously though, you are playing with fire and so far you have been lucky.

[rgbrown@itexas.net]

Gerald,

I thought you were going to ask for address to send flowers and next of kin............

Ron Brown - rgbrown@itexas.net (mailto:rgbrown@itexas.net)

If Stupidity got us into this mess,
then why can't it get us out? - Will Rogers

[Ross Kowalski]

Wow, sounds like the jacobs chuck for your porter cable isn't a popular option!

I will put my good dial on it tonight, but I am confident the shaft is true and I wouldn't use this setup for anything bigger than 1/4 inch bits and only under 16,000 with a slow feed.

A friend of mine had a shaper head let go last winter and hit him in the chest. If it would have hit his head it likely would have been lethal. I don't take fast spinning metal lightly.

[gerald_d]

Ross, glad to see that you understand our concern.

Would also suggest that you stand with an X-rail between yourself and the cutter. When things go wrong, the chunks normally fly fairly flat along the table.

We still have a broken-off tip of a 1/4" cutter stuck in the drywall of the shop about 4' from the ground . . . . . .

[Ross Kowalski]

Point well taken.

I extended the rail around the ends of the table this morning as a precaution. Now there is the vaccum foot as a first line of defense and a X-rail that goes around the entire perimeter of the table as a second.

Thanks,

Ross.