New 5C collet chuck run out

[???]

Bought a 5C collet chuck from my Chinese manufacturer/supplier. Set it up in the four jaw chuck and clocked it to within .002 mm TIR at the back and then in the taper portion at the front. Using solid carbide rods to check run out I am getting about .002 mm TIR on the rod ( I think that is .00008" TIR so less than half a tenth off center). For those of you who run the 5C collets a lot is this the expected run out? I am planning to use this on the cylindrical grinder to grind my standard diameter parts. My only other experience using 5C was on a Kellenberger cylindrical grinder but that was a more than 20 years ago.

 

[L Vanice]

Don't overlook the accuracy of the 5C collet itself. Perhaps your grinder has an inside grinding spindle that would allow you to true up a collet held in the 5C chuck. You can also get soft emergency collets that can be bored in the chuck.

Larry

 

[guythatbrews]

80 millionths is better than 5c expected runout.

Here's what hardinge says:

"Special-Accuracy 5C Collets are available. When held in a Hardinge Super-Precision® spindle, they are guaranteed to have a maximum TIR of .0002" for 5C round collets, and .0005" for 16C, 20C and 25C round collets over 3⁄16" (4.76mm) to the collet’s capacity measured 1" from the face of the collet."

It surpises me it is that close, especially at 1" overhang.

 

[???]

I

Don't overlook the accuracy of the 5C collet itself. Perhaps your grinder has an inside grinding spindle that would allow you to true up a collet held in the 5C chuck. You can also get soft emergency collets that can be bored in the chuck.

Larry

The chuck that came with it is jammed on permanently but I think it's a 3 MT. My plan is to cut the chuck off with a slitting disc and then internally grind out the male taper tills it's paper thin then pick it out. I think it may have been put in wet and it's rusted in. There's no way I'm belting on it with the high precision bearings in there.

 

[Donkey Hotey]

I gots nothing to add but, if you're splitting tenths, I bow to your commitment.

 

[???]

I gots nothing to add but, if you're splitting tenths, I bow to your commitment.

Just wanted to make sure the baseline accuracy is there in the chuck and those that use them think this one is accurate enough.

My boss when I was a plastics mold maker always said I suffered from micronitis but I do like working really accurately.

 

[Donkey Hotey]

I meant that 100% as a compliment. I too try to hold stupid accuracy wherever possible. It's good practice for when you really need it.

 

[rons]

80 millionths is better than 5c expected runout.

Here's what hardinge says:

"Special-Accuracy 5C Collets are available. When held in a Hardinge Super-Precision® spindle, they are guaranteed to have a maximum TIR of .0002" for 5C round collets, and .0005" for 16C, 20C and 25C round collets over 3⁄16" (4.76mm) to the collet’s capacity measured 1" from the face of the collet."

It surpises me it is that close, especially at 1" overhang.

Hardinge spindle nose is specified at +/- .000025" or .000635mm

 

[???]

I suppose I shouldn't be worried considering what I paid.
1 off 5C collet chuck.
25 piece 5C collet set.
24 piece ER 40 high precision collet set.
5 straight shank150 mm long ER40 collet holders .

Edit +60 BT 40 pull studs and 60 BT30 pull studs.

USD 573 including shipping to Sydney.

I have been very fortunate having developed relationships with manufacturers in China that make high quality gear.

 

[technocrat]

In my experience, a lot of chinese stuff is really good, you just can't rely on it and need to check each part.

 

[eKretz]

I'd say that's excellent. I made my Hardinge 5C collet chuck a Set-Tru, just to be sure.

 

[implmex]

Hi ???:
I'm with eKretz on this one...my 5C is also a Set Tru.
I use that feature pretty rarely since my 5C is set up on the Monarch lathe, and IMO split tenths is bullshit for turning so it's been overwhelmingly as good as I need.

But as other s have commented, collets do run out and the odd time when it has to be chucked in a collet and has to run out as little as I can get, I whip out my tenths clock and dial in the collet.
I rarely have to adjust more than a couple of tenths but I run Lyndex collets and they are pretty good.

On a cylindrical grinder it may pay for you to get better collets.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com