Rock Chuck vs. Carve tight? in the need of an upgrade

[mtylerfl]

...The thing regarding the slippage of carbide in collets made my machinist friend laugh so hard that he almost fell over-- he's been working with high speed collets and carbide for many many years and he says "anyone that thinks that this is a real and true concern should give him a call because he's got some bridges to sell them" According to him there is always SOME slippage over many many many revolutions but that this is such a remote occurance in most industrial situations that it is not even a consideration and that this is for industrial machines that run all day... only stopping to change out worn bits...Lawrence

Hi Lawrence,

Your machinist doesn't have the full story on the chuck used by the CarveTight and Rock Chuck. They use a "paw" to grab the bit shank. He's probably familiar with the commercial "ER"-type chuck collets (which are patented). They are waay different than a "paw-style" chuck collet, and there is really no valid comparison between the two. I use the ER chuck collets on the ShopBot and there is no slippage on any bit as long as it is tightened properly and not worn out. BTW, ER collets are a little pricey - I spend between $45 and $65 on each.

[lawrence]

Hi Lawrence,

Your machinist doesn't have the full story on the chuck used by the CarveTight and Rock Chuck. They use a "paw" to grab the bit shank. He's probably familiar with the commercial "ER"-type chuck collets (which are patented). They are waay different than a "paw-style" chuck collet, and there is really no valid comparison between the two. I use the ER chuck collets on the ShopBot and there is no slippage on any bit as long as it is tightened properly and not worn out. BTW, ER collets are a little pricey - I spend between $45 and $65 on each.

That's a very fair point-- he didn't look at things too closely other than to say that he could see why I would rather use the rock over the QC after looking at them for about 20 seconds.

Lawrence

[jaroot]

I put the Carvetight on our machine mostly because we had other issues with the z truck. I have to say that it was without a doubt the best money that we've spent on the machine.

[bergerud]

There may be a new option soon. I am currently talking with an American company who manufactures high quality ER spindles and is interested in offering a line which fits the Carvewright. (Next step is sending the him exact dimensions.) Pull out the old spindle with whatever is on it and replace it with a industry standard collet chuck. Price and time line yet unknown. (A set of seven ER11 collets, however, {1/32,1/16,3/32,1/8,3/16,7/32,1/4} is $58 at www.Shars.com.) If you cannot make your own ER spindle, you may be able to buy one soon.

[rjustice]

As a side note, I created ER style bit adapters but never put them on the market because after testing them, i found that they were a pain in the neck to change out using 2 wrenches in the machine. Being a machine user, it was obvious that i wouldnt be happy with this style of chuck. In terms of clamping pressure using the Rock Chuck, the amount of pressure it takes to slip the bit far exceeds the potential of the machine spindle.

Hope this helps,

Ron

[bergerud]

It is true, the two wrenches are a drag, especially if you are into mult-bit projects. I, on the other hand, use my router for those other jobs. It is most important to me that I can hold any size bit and hold it accurately. I use 3/32 shank diamond burrs, many 1/8 shank square and ball end mills, and now 3/16 shank ball and square end mills as well as the 1/4 shanks. I have no use for 1/2 shank bits and I cannot understand why anyone would.

The time I wait for the machine to go through its checks and questions slows me down more than two wrenches does. But still, I am going to put a locking push button on my truck (there is a spot just made for it) so that I 'll be back to one wrench.

I also like these ER spindles because their run out can be made almost unmeasurable, and this is important for a few good reasons. They are small and light and that is exactly what I think should be on the end of a flex shaft. Actually, is not the reason for a flex shaft in the first place to have a light, low inertia truck?

You are right, two wrenches are a pain, but I think a small price to pay considering all of the other advantages. You know, the whole "quick change" concept has been the cause of all the problems from the start.

I am not trying to make any money on this. I am only interested in the best solution. I commend your efforts to help the Carvewright users, to me, you are a hero. To your credit, I think LHR copied your solution. For many users, your Rock (and now also the CT) are what is needed. I think, however, that there is a small subset of "advanced" users who want more freedom to experiment with the huge selection of (non proprietary and cheap) carbide bits on the market.

I was actually hoping the either yourself or Jeff might want to take over the business of providing these ER spindles. Some people can make them for themselves, but this is yet, I fear, a very small subset.

[rjustice]

I can offer up some solutions if interested. The Rock sleeves are available in 1/8, 1/4, and 3/8 ID... I will be releasing the 3/16 very soon, and could look at 3/32 if there is an interest. The runout on the Rock Chuck is extremely tight based on the interfacing method, generally less than .0005 TIR. I checked runout in the 4 QC's that i had and they were .012-.015. Obviously this is the root of vibration no matter how well the chuck was balanced.

If there is interest, I can supply the Rock or ER style nose on an integral spindle, and yes, make it lighter. I can also supply the ER style bit adapter, that would allow users that have the Rock chuck to simply unscrew thier Rock bit adapter, and screw in the ER bit adapter.

Feel free to click on my email link in my signature below if you are interested.

Thanks,

Ron

[Sallen1215]

Ron

I have a used machine shipping to me, it has the QC on it and comes with a bunch of bits set up for the QC, if i get the rock chuck kit can i use all of the bits with your system? i know with the carve tight i have to get their bits with the pressed on bearings for the 1/16 and the 1/8 stock bit. I think i read one of your posts that the pressed fittings were overkill and the chuck can tighten down on the bits with no problem.





Thanks for the help
Stephen

[rjustice]

Hi Stephen,

Yes the Rock Chuck system gives you complete flexability to use any bits you wish to use. I already have 1/8, 1/4 and 3/8 sleeves, and will soon have the 3/16 offered on the website. The Rock Chuck will not slip using the sleeves that I produce as long as the sleeves are oriented, and tightened properly. There are a few rules of thumb if you are going to try aftermarket cutting bits...

1) Be sure they are center cutting (flutes are sharpenend to the center on the tip of the bit)
2) Use carbide
3) Choose a bit size in the library that is of similar size so that the feeds and speeds are approx. correct.
4) Make sure there is enough flute length to cut the entire depth that you are going to carve. If you hit the shank of the tool, it will create excessive force, heat, and potentially start a fire, and/or damage the machine... (NOT GOOD!)

Hope this helps..

Ron

[Sallen1215]

Thanks Ron i don't plan on buying aftermarket bits unless they come from you, however all the bits coming with the machine will be QC style and i will just remove the QC collar and use your system as long as it works that way. And believe me i hope it does cause i cant afford a whole new set of bits, that would suck so bad ha ha