Square/Hex 5C Collet Block Recomendation

[gzig5]

I'm looking for a recommendation for a good quality collet block set. Cheap as possible of course . There are a lot of them out there in the $50-$70 range but if they are not concentric within +/- .001" I don't want to mess with them. Don't want to spend $200 either. So, any good news or bad news stories for these?

[rkepler]

Checking my cheap import square collet block (bought from MSC some 20 years ago?) I see about .0012 out on 2 faces zeroed against one of the opposite faces. When I check the same collet and gage pin (a pretty near new Hardinge 3/8 and a good .375 pin) in the lathe spindle I see something similar. The collet chuck has maybe .0002 runout, so it might be in the collet and not the square block, but the square block needs it's faces lapped to get some vise nurds off.

So I would say that you *can* get a good block, but it's unknown if you will.

[Toolguy]

Just get the cheap ones and touch up whatever needs it. Carbide tooling on a lathe will work. More expensive ones may not be any better until you are paying $400 each from someplace like Suburban Tool.

[BCRider]

So buy the cheap set and massage it to make it as accurate as what you are looking for.

The truth of it is that "cheap" and "guaranteed accurate" cannot be applied to any item. But.... I said "guaranteed accurate" because there's always the chance that the cheap set you buy is within that accuracy level. It's just that it's a gamble if you buy cheap where it's certain if you pay the big bucks.

Because the accuracy on the cheap stuff is variable within a given batch and variable from batch to batch I'd suggest that there is also not much point in asking. Even if you find two or three folks that have good results with their 10 year old Brand X there is no guarantee that buying today's Brand X set will turn out to be as accurate as you're after. Different batch and likely even from a different maker. Just happens to be the same domestic importer.

Then again what are your collets like? If you're using cheap import collets then is any measured runout due to the block or the collet? Or does the collet runout add to or cancel out any block error when used with specific import collets?

In the end you're clearly not willing to pay the big bucks. So buy a set of the cheapies and using a DTI and surface plate check the blocks out for centering and parallelism. Then lap or otherwise "fix" them to bring the total runout of the blocks to within your desired .001.

Toolguy mentions machining them. But I'd seriously hope that they are not THAT far out and that simply lapping them on some suitable surface would be enough.

[EddyCurr]

Is your mind set on using 5C collets or have you considered ER collets of some size for what you want to accomplish?

Either way, take a moment to go to arceurotrade.co.uk and search on "collet block" for a look at the pairs of hex/square blocks they carry for 5C and ER collets.

I own a set for ER collets and like them.

.

[J Tiers]

If you really want cheap, you can make your own.

It will be as good as you care to make it, and as your machines will allow. It just takes more care to get it just how you want it. The dimensions are available on-line, and dimensions for a whole bunch of collets were published, IIRC , in the magazine of our sponsor possibly 10 years ago.

This one is for 3C, but you could make for 5C just as well



You will just be trading time and trouble for cost. I had a piece of hex stock, which was surprisingly accurate, but you could also mill your own, after boring. That would let you get it as close to perfectly centered as you want. I went the other way, and centered the bore in the hex.

[Toolguy]

Toolguy mentions machining them. But I'd seriously hope that they are not THAT far out and that simply lapping them on some suitable surface would be enough.

Lots of good information in that post, BCRider. That's how it really is.

When I say machining, I'm talking about taking a skim cut of one or a few thou., just enough to clean up all the way around, plus another thou. or two to make sure it did totally all clean up. I bought a 5C collet chuck for the spindle nose. When mounted, the 5C taper had about .002 runout. Not real bad, but not nearly what I was hoping for. I set up the compound on the taper and used a 3/4" carbide insert boring bar with short overhang to recut the taper. I probably took off .003 to .004 total. Now it has maybe .0001 runout. You can barely see the needle move on a .001 graduation dial indicator.

[dalee100]

Is your mind set on using 5C collets or have you considered ER collets of some size for what you want to accomplish?

Either way, take a moment to go to arceurotrade.co.uk and search on "collet block" for a look at the pairs of hex/square blocks they carry for 5C and ER collets.

I own a set for ER collets and like them.



.

Hi,

The ER collet blocks are interesting, but I think that 5C's are still preferable. Simply because 5C's ae available in other shapes not just rounds. They can be had in soft form to machine into custom shapes also. None of which is available in the ER collets.

To OP, unless you need to do certified work for a paying customer who requires a metrology paper trail, don't sweat it too much. Buy whatever is financially prudent for you.

Dalee

[DR]

AFAIK, there are no brand names in collet blocks. They all seem to be unbranded generic. Buy from a place with a decent return policy using a credit card. Return if not satisfied.

[BCRider]

....When I say machining, I'm talking about taking a skim cut of one or a few thou........

Gotcha. And yes, that would certainly be a valid option. I was thinking that it would be nice to keep the blocks closer to their original sizes. But really what does it matter if they are a skim cut per face smaller or not? Precious little I suspect. To keep the measurements simpler I'd still want to make the dimension from the center axis to the faces SOMETHING that makes for easy math though.

This raises a question on using the hex blocks too. I'm sure I'm not the only one that puts the flats between the jaws of my milling vise. But who is to say that the ridge between the lower two faces that registers on the bed of the vise is true or not? I'm thinking that setting up a gauge pin in a collet or even a section of ground drill rod and leveling it then skimming the apex angles in the mill would not be a bad thing to do.

In fact this thread is giving me the idea that I'm going to check my own 5c blocks out for parallel and other alignment issues to see how true they are. I know these are not items to be used where absolute accuracy is required. But it would be nice to know how far out they are and if it's not a lot of work to correct them to do so. It's nice when even the non critical work comes out more tidy than we expect.

Hi,

The ER collet blocks are interesting, but I think that 5C's are still preferable. ....

I do believe that this is one of those "BOTH is BETTER" options.

I had no idea that ER32 collet blocks are available. I'm just in the process of getting into the ER32 collet game and I think I'll be looking for a set of ER blocks to sit beside my 5C blocks. And now that I know such things are available I'll be looking for a set of blocks to go with my other ER chucking options. After all the ER collets will hold a wider range of round size work neatly axial which won't sit stable in a "strained" 5C collet.