ER32/ER40 or 5C? Whats your choice and why?

[projectnut]

5C collets we’re invented in 1901. They’ve been in use for nearly 125 years. Better ones like Hardinge advertise runout of less than .0002”

Hardinge used to state in their brochures the gripping range was -.007” to + .008”. I have found that to be accurate with their collets.

Cheaper brands advertise run out to be as high as .0006” and have a grip range of -.001 to +.010”.

I have never had a problem with Hardinge collets producing tapered or otherwise inaccurate parts

 

[GrifterGuru]

5C collets we’re invented in 1901. They’ve been in use for nearly 125 years. Better ones like Hardinge advertise runout of less than .0002”

Hardinge used to state in their brochures the gripping range was -.007” to + .008”. I have found that to be accurate with their collets.

Cheaper brands advertise run out to be as high as .0006” and have a grip range of -.001 to +.010”.

I have never had a problem with Hardinge collets producing tapered or otherwise inaccurate parts

@projectnut

Who mentioned tapered parts??

The comment made by @epanzella was/is about a 5C Collet closing to a tapered bore due to single end slotting Vs ER which closes equally due to dual end slotting.

5C collets are only slotted on one end so they only collapse on one end. The more you have to squeeze down the collet the more tapered the bore of the collet gets.

ER collets are slotted from both ends so that both ends collapse equally to grip a part without the bore getting tapered. This gives each collet more range in the parts it can hold.

 

[epanzella]

TORMACH rates their 5C collets to hold parts +0.0 to -.004
My own personal limit has always been +0 -.005
Grifterguru, thanks for the clarification above.

Tormach Toolholding - 5C Round Collet Set 35 Pcs. - Inch - SKU 34727

The 5C Round Collet Set (35 Pcs.) is a 35 piece 5C round collet set that covers 1/16 in. to 1-1/8 in. nominal diameters (1/32 in. increments)

tormach.com

 

[Ischgl99]

TORMACH rates their 5C collets to hold parts +0.0 to -.004
My own personal limit has always been +0 -.005
Grifterguru, thanks for the clarification above.

Tormach Toolholding - 5C Round Collet Set 35 Pcs. - Inch - SKU 34727

The 5C Round Collet Set (35 Pcs.) is a 35 piece 5C round collet set that covers 1/16 in. to 1-1/8 in. nominal diameters (1/32 in. increments)

tormach.com

I have a set of metric 5c collets from Precision Matthews and they can take a gage pin 0.001” larger than nominal size, but I also have a Lyndex 3/8” collet and that can go 0.008” larger. It seems from my limited experience the import collets are basically on size or smaller, but the name brands might give you a plus tolerance as well. I need to get some more quality collets and see if that holds true. It is a PITA to remember to machine everything undersize for metric collets and I might end up replacing them if the good ones give you a plus tolerance as well.