ID workholding 5c expanding collet

[zschary]

I need to run some parts that need to be held from the ID.. from .65 to around .8 or .85.. I am using 5c expanding collets.. If i had to cover the diameter of .65 up to .85, how many steps would i need per collet, or how many, in other words what is the latitude each step could cover? If someone has experience with them and can help with a machining process for them i would appreciate it.. The ID 5c is on the subspindle so i have to think about the pick off as well and clearance for the next step inside the bar.. Is there another ID workholding idea that is not too expensive?
thanks in advance

 

[zschary]

i will only need the width of about .2 on each step..

 

[VTM]

If I understand your question correctly you are going to need 3 steps. .05 expansion Is huge for expanding collets. You'll need 3 steps I'd say within .005 of your I.D.'s

 

[sfriedberg]

Ordinary 5C collets have a very small grip range. That is, very little allowance for bore/part mismatch. If you want good holding, 0.002" at the very most, and 0.001" is definitely better! Assume 5C expanding collets have similar characteristics. So I would abandon the idea of having a set of 5C ID-gripping step collets for the entire 0.65-0.8 range. Instead, cut expanding collets for your actual parts.

 

[zschary]

Ordinary 5C collets have a very small grip range. That is, very little allowance for bore/part mismatch. If you want good holding, 0.002" at the very most, and 0.001" is definitely better! Assume 5C expanding collets have similar characteristics. So I would abandon the idea of having a set of 5C ID-gripping step collets for the entire 0.65-0.8 range. Instead, cut expanding collets for your actual parts.

I have been realizing that.. I looked at the Royal system to id grip, but a bit much right now for the work.. does anyone have other ideas on ID gripping? a2-6 spindle, I will need sizes in between the above dimensions, would be a big amount of 5c's, but that is possible with a couple few steps on them .. Guess i need more chuck movement?

 

[???]

Can you use soft jaws?

 

[ManualEd]

If you want cheap, its hard to get cheaper than a MiteeBite ID expansion clamp.

You machine them to whatever size you need so they should have pretty decent runout.
The bolt actuation would be slightly less convenient than hitting the chuck foot pedal, but it might be fine for your application.

 

[SeymourDumore]

does anyone have other ideas on ID gripping? a2-6 spindle, I will need sizes in between the above dimensions, would be a big amount of 5c's, but that is possible with a couple few steps on them .. Guess i need more chuck movement?

First, chuck movement ... .007 worth of grip is about the absolute max you get out of a 5C, let it be ID or OD, I usually bore/turn collets when they are no more than .004 collapsed/expanded.

Second, the best system out there that I've found is the Hardinge expanding collet setup, like this: https://shop.hardinge.com/All-Produ...anding-Collet-Body-(5C-70-1)/p/11410000000000

Anyone can show me something that outdoes that 5C rig, I am all ears!

 

[???]

First, chuck movement ... .007 worth of grip is about the absolute max you get out of a 5C, let it be ID or OD, I usually bore/turn collets when they are no more than .004 collapsed/expanded.

Second, the best system out there that I've found is the Hardinge expanding collet setup, like this: https://shop.hardinge.com/All-Products/Workholding/Collets/Expanding-Collets/5C-Expanding-Collet-Body-(5C-70-1)/p/11410000000000

Anyone can show me something that outdoes that 5C rig, I am all ears!

Do these come in different sizes or is there a base size with different sized rings that slip over it?

 

[SeymourDumore]

Do these come in different sizes or is there a base size with different sized rings that slip over it?

If you look at the 2nd image in that link, it shows that there is a 2" dia steel, and a 3" dia AL pad available, each with a corresponding 2" or 3" limit ring.
When assembled, the back of the pads are just under 2" or 3" diameter.
Then you pull the limit ring over that diameter, close the collet ( expand it into the limit ring ) and machine the diameter exactly to size.
When done, remove the ring and the result is a virtually zero runout expanding collet with a known amount of expansion every time.

As far as the range, that same link also shows that the 2" steel gives you a range from 1/4" to 2" ( I've managed to go as small as 3/16 but with very low clamping force ), and the 3" AL pad can go from 3/4 - 3" dia, though I do have some going down to 3/8, also with very low clamping force using air operated chucks.

Now, to be more inventive, I have made my own AL pads that go up to 5" dia with a matching limit ring, but one needs to be careful with the RPM-s due to the inertial forces.

Again, these are the cat's meow for 5C ID clamping!

 

[???]

Pity they are unobtanium at those prices here. But that's the price of selling your soul to the devil of globalisation I guess.

 

[michiganbuck]

I did a lot of parts off the Id using, mandrels between centers, and one-use stub mandrel out of a chuck.

A stub mandrel held in a 4jaw chuck can be used many times.
Still , not that good sometime for a production part.

 

[SeymourDumore]

Pity they are unobtanium at those prices here. But that's the price of selling your soul to the devil of globalisation I guess.

On that note, can't you guys ( me thinks you're in NZ ) just order straight from Hardinge?

 

[rjwalker1973]

Can you not use turned chuck jaws clamped in the id? Still limited by stroke of course but you would get parallel movement from the 3 jaws that is more consistent.

 

[???]

I'm in Australia. Exchange rate is prohibitively expensive at the moment. Fortunately or unfortunately for me I have an insatiable desire to possess more cool tools. I've just ordered 5c collets and a 5c chuck for my manual lathe from my dare I say it Chinese supplier. Most of my work is one offs or short run for my own products so it would be really nice to have foot pedal operated opening and closing etc. but not totally necessary in my case.

 

[zschary]

On that note, can't you guys ( me thinks you're in NZ ) just order straight from Hardinge?

I am here in the states.. The hardinge idea is a good one, better then the normal expanding collets, but still limited to stroke.. Is there a place to buy the 2" steel pads for the hardinge 5c? not seeing them around.. Also i do have a 6" chuck, what about turning down jaws to small diameters on that, do you have better precision etc on using collets?, i had not thought of that idea until mentioned above. Thanks for all the input here by the way

 

[crossthread82]

I am here in the states.. The hardinge idea is a good one, better then the normal expanding collets, but still limited to stroke.. Is there a place to buy the 2" steel pads for the hardinge 5c? not seeing them around.. Also i do have a 6" chuck, what about turning down jaws to small diameters on that, do you have better precision etc on using collets?, i had not thought of that idea until mentioned above. Thanks for all the input here by the way

Hardinge makes a 5c collet expanding mandrel system:
https://shop.hardinge.com/All-Products/Workholding/Collet-Accessories/Arbors/#200-5C-Expanding-Collet-Arbor/p/18710000000200

They sell the sleeves that slide over the arbor linked above.

 

[SeymourDumore]

I am here in the states.. The hardinge idea is a good one, better then the normal expanding collets, but still limited to stroke.. Is there a place to buy the 2" steel pads for the hardinge 5c? not seeing them around.. Also i do have a 6" chuck, what about turning down jaws to small diameters on that, do you have better precision etc on using collets?, i had not thought of that idea until mentioned above. Thanks for all the input here by the way

Forget the stroke limit!!!
If you need concentricity and grip, you would have to machine the correct diameter regardless of what you use.

As for not finding it, that is because Hardinge has the worst fucking webstore EVER to find shit in!!!
Here it is: https://shop.hardinge.com/All-Produ...el-Master-Pad-Set-(5EC-70-4)/p/11470000000000
Here is the 3" AL one: https://shop.hardinge.com/All-Produ...um-Master-Pad-Set-(5EC-70-7)/p/11530000000000

 

[zschary]

Forget the stroke limit!!!
If you need concentricity and grip, you would have to machine the correct diameter regardless of what you use.

As for not finding it, that is because Hardinge has the worst fucking webstore EVER to find shit in!!!
Here it is: https://shop.hardinge.com/All-Products/Workholding/Collet-Accessories/Pads/Master-Collet-Pads/2”-Steel-Master-Pad-Set-(5EC-70-4)/p/11470000000000
Here is the 3" AL one: https://shop.hardinge.com/All-Products/Workholding/Collet-Accessories/Pads/Master-Collet-Pads/3”-Aluminum-Master-Pad-Set-(5EC-70-7)/p/11530000000000

ok stroke limit forgotten.. Just always want easier and less tools, though the answer is usually that its harder and requires more tools.. haha.. So more collets.. I spoke to hardinge about the tools mentioned here.. Because the part is narrow they dont recommend the ID mandrel system mentioned above although that looks great for some things, its more expensive, they recommend this system above with the collet pads above, i can cut a couple three sizes on each.. i found 6 of them on ebay with the 5c part and the pads and bought them, so i am cooking .. I will buy some more pads from Hardinge and cut them with precision for each size like you said.. thanks all for the input..

 

[Triaged]

If it isn't for production you can make your own.