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View Full Version : Rock Chuck split collet in CarveTight spindle?



jkpq45
05-15-2019, 11:04 AM
I'd like to run 1/4, 1/8 and 3/8" shank bits in the CarveTight. Can I use the two-piece/split collet for the Rock Chuck with these diameters of bit, and hold securely in the CarveTight?

Can the Rock Chuck collets hold solid carbide tooling, or are they only for high speed steel like the CarveTight?

Thanks!
jkpq45

Digitalwoodshop
05-15-2019, 11:20 PM
I don't have a good answer for this question... It will be a trick to get the split collet in the right position where the bit wedge is effective in holding it tight. If you got the collet turned where it was not pinching the internal bit then you could have a problem. The Rock Chuck had 1/2, 1/4, and 1/8 inch options in the heads provided but that is not an answer since you have a CT.

I think it is going to be a Gamble.... And you are likely to loose.... I had a 60 degree bit fly out of the original QC and as I was walking out of the shop it hit the clear plastic door pushing it open enough to shut down carving before falling back inside the machine.

I use a Set Screw type bit holder with a 1/4 inch shank to hold my 1/8 inch Circuit Board Bits. I also have a 1/2 inch bit holder that holds a 1/2 inch bit that is really a Bit EXTENDER. I bet you would have better control over putting a bit in the bit holder and setting the SET SCREW with a split collet with the 1/2 inch to 1/2 inch bit extender.

This is 1/2 to 1/4. https://www.rockler.com/rockler-router-collet-extension-for-1-4-in-shank-bits

This is 1/2 to 1/2. https://www.rockler.com/rockler-router-collet-extension-for-1-2-in-shank-bits

Both Rockler options require METRIC Wrenches and were given bad reviews because of it... I think that is unfair...

My 1/4 to 1/8 is a Roto ZIP Bit Holder. Caution Roto Zip Bits are soft and can bend... Not for CW.

There is a new "After Market" non LHR product in development that uses a standard router bit holder in 1/2 and 1/4. It will be a single shaft like the CT when it goes into production. So you could convert your QC type truck or even a CT Truck to work with a standard router bit holder by replacing the SHAFT. Not a project for everyone and likely be offered as a service... Swap your shaft. Rather than swap with a Truck as there are at least 3 flavors of TRUCK... And sending in one with no holes and getting back one with the black washer on the one screw hole that likes to SNAP the Casting would not be good for reviews. So what you send in you get back.

As far as 3/8 inch bits... ??????


AL

CarverJerry
05-17-2019, 12:55 PM
I have a Rock Chuck with the 3 collets Al talked about, I only run solid carbide bits but the collets will hold both carbide and high speed. Being the 40+year machinist that I am, I used many different collets and it doesn't matter if it's carbide or high speed, it's the diameter of the shank that matters. Hope this helps.

cnsranch
05-18-2019, 10:19 PM
Jerry.....I'm a little confused. I've always been under the impression that carbide shafted bits would slip in the CT adapters.....only use steel. Do you disagree with that?

CarverJerry
05-21-2019, 08:45 AM
I totally disagree with that. If you ever experience slippage with a tool because that tool may be slightly undersize (which is very uncommon) you can use a little chalk on the shank to make it hold better. an old trick us old timer machinists use.

cnsranch
05-21-2019, 09:14 AM
Thanks Jerry

bergerud
05-21-2019, 07:51 PM
I like the chalk trick. Have to give that a try. I have had problems holding carbide bits in much better chuck systems than the CT split collet. Smooth carbide bits plus resonant vibrations can "walk" out of the tightest collects. The long bits, especially, are really hard to hold. Only the press fit CT adapters seen to be able to hold the long bits. I think it has to do with high frequency sound waves traveling through the shank.

Rocketman
07-13-2019, 03:41 PM
I like the chalk trick. Have to give that a try. I have had problems holding carbide bits in much better chuck systems than the CT split collet. Smooth carbide bits plus resonant vibrations can "walk" out of the tightest collects. The long bits, especially, are really hard to hold. Only the press fit CT adapters seen to be able to hold the long bits. I think it has to do with high frequency sound waves traveling through the shank.

I agree with Jerry that an undersized shaft in a collet is a problem. It will cause the end mill to either spin in the collet or walk out or both. Cheap Chinese collets are another problem. Often they are not hardened properly or made out of softer steel that can't be properly hardened. They tend to deform when clamping down on a hard carbide shaft if it's not the exact size. Once deformed they are junk. Also if a bit ever spins in a collet it is probably junk also. A spun tool deforms the collet and the heat from spinning changes the temper of the metal enough that if not deformed it soon will be.

Another problem with both of these chuck designs is the screw being offset to one side. Unless these are balanced (and I don't think they are) the vibrations you mention will work against you. A collet holder usually has a hex head nut that the collet snaps into and since there are no screw imbalances on one side or the other they run true and vibration free. Changing tools is more cumbersome with a conventional collet nut spindle but increased tool life from reduced vibration is real.

Another common problem of collets in a machine shop is they crack. Usually a result of a machinist using the wrong sized collet for the end mill or drill bit he's trying to grip. Sometimes you need five tools for a setup all with the same size collet and you only have four. Machinists will grab one that's close and put one of the less critical tools into it to get the job done. Over time your collets get destroyed and you need to replace them. They are not designed to last forever.

Split collets work in a machine shop for less critical work. It's almost impossible to get them to run true enough for critical hole sizes. With the Carvewright designed for wood your never going to need or meet the tolerances needed in a machine shop. In a machine shop with most older equipment topping out at 4500 rpm's split collets can be useful. Start spinning tools faster as in modern machinery or wood working tools and you have vibration to contend with. For the higher spindle speeds they use balanced tool holders and even heat shrink tools into the holders with special tool changing heaters that the tool holder companies provide.

DickB
07-19-2019, 12:02 PM
I use an ER11 adapter for this. Never a problem. Surprised you didn't mention it bergerud.


87632

tackytim
07-21-2019, 11:20 AM
Al had mentioned a product in development which is a spindle I designed to replace my QC chuck. It essentially is just a spindle with an inside taper and outer thread to match a standard Porter Cable router collet. I feel this is better than the Carvetite only because of the balance issue caused by the holding screw. It could also be made to use an ER collet and nut.

Unfortunately, I dont have extra time to devote to it to make enough to try and market them AND keep the Y shafts in stock. Also, since the Carvetite is certainly more reliable than the QC, I'm not sure how many would be interested anyway.

I have made my own press fit adapters for my carbide bits and have had no issues with my setup. I have not attempted split collets on solid carbide bits, and based on others experiences I'll stick to the press fit ones.

Just my .02