Collet to put 1/8 " ZIp bits in porter cable

[flyboy]

I just finnally got my shopbot going. I have to say that they did a great job with thier part. Building my own steel table was a pain. But it's all over now
I want to use zip bits in my porter cable which came with 1/4" and 1/2" collets and I can't find a source for an 1/8" collet. Does anybody have any ideas?

[fisheye]

I got some from MLSC 1-800-533-9298 or mlcswoodworking.com $4.00 each or $19.95 for a 7 pcs. set.

[rgrim]

The stores that sell rotozips has a 1/8-1/4 collet
be cause the new rotozip can take a 1/4 bits

[beacon14]

Porter-Cable makes a 1/8" collet. You may have to look for it. We called our local P-C factory repair center, they said they didn't have one (twice) but could order it, then we called back the next day and lo-and-behold, they had two.

[gerald_d]

Just for our interest, what do rotozip bits cost and are they made of solid carbide?

For 3mm cuts, we are using a stepped Belin bit that has a 6mm shank and a 3mm nose. Solid carbide, spiral, price around $17 (ex-factory France). Belin also does inch sizes but they are more expensive.

[flyboy]

Well, I found the collet that zip bit sells so I tried them out. I broke three of them within a couple minutes. They flex very easily. I put in an 1/8th end mill and that worked much better. More expensive though. The good thing about zip bits only cost $7 for a pack of ten, I may just have to run slower.. I had a problem with my bot today. It was doing strange things. I would run a program to practice and then move the tool to a new postion and "Z3" so I could do it again but then the tool messed up the program big time. It was all wrong and ugly three times it did this. I was just making a 1 1/2" "OK" letters cut out in the mdf. It didn't repeat the program twice the same way. The first time was perfect, then they were all messed up and ugly. What's the problem? I had changed the speed and ramp values to keep from breaking the zip bits but I don't know why that would cause a problem. I've run some other CNC equipment for years and have never seen this.

[cmrtom]

I am using a cutter from Severance Tool. I can get just about any type and shape that I want. You can get solid carbide with a tiny point and 1/4 inch shank. Basically high grade die grinder bits.

I have also now available a Jacobs chuck, with a 1/2 inch straight shank. Just use the 1/2 inch collet and any size bit from tiny to 3/8

Works great

[bwclark@centurytel.net]

Thomas,

I hope that you are not using a Jacobs chuck in a router. First off, they are not designed for side loads. Second, I think that Jacobs states that the maximum safe RPM is about 3000 for their chucks.

Also, I have always had a lot of run out on a Jacobs chuck. Put a bit in your dill press chuck and then put an indicator on the shank. You will see at best about .003" runout (at least that is the lowest I have seen).

Anways, I am sure you know all this.

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

[davidallen]

roto-zip bits are VERY sensitive to placement in the collet. you need a solid 1/8" of shank showing below the collet. if you clamp it too high, the flexing will cause metal fatigue very quickly and the bit will break.

this means though that you'll have nearly 2" of 1/8" bit sticking out below the collet. if you try and side-load the tip, it's going to wobble like mad. again, causing a lot of flexing and breaking the bit. if you cut near the collet, the wobble isn't bad. but that means you need a couple of inches clearance below the surface of the material.

[cmrtom]

Have used the Jacobs chuck now for 2 years

Just have to be sure and tighten the cutter very carefully as they will loosen up.

Yes there is a little more runout but nothing that is crazy...... still using the same router as well. But have another set of bearings on hand just in case.

Is the solution I needed