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.

 

[Illinoyance]

For my South Bend 10K I have 6K, 3c, an ER32 collets available. On my Nardini I have 5C and Jacobs Rubberflex available. My indexers use 5C. The mill takes R8 but I have ER16 and ER32 collet chucks. My D-bi grinder used R8 collets but I often use one of the ER collet chucks. My watchnaker's lathe uses ER8 in the tailstock. 6K, 3C, 5C, and R8 hold a specific size. ER collets hold a wide range of sizes, 1mm range, except for the smallest sizes.

 

[GrifterGuru]

Now, see, this is why I have no real use for 5C. My lathe has little enough room as it stands and using a 5C chuck just eats up too much usable space, my ER collets cover my needs as well as the fact that 5C takes so much more storage.

My 6J chuck takes up to 38mm hex, my 3J can take a larger hex than the 6J and my 4J chuck is great for square stock. All of which to say, what I have in hand negates any real use case for 5C when combined with my ER collets.

I still have no idea what to do with the chuck or collets other than to sell them on, given I have no use for them.

 

[Charles scozzari]

Because of the machines I own I stay with R8, MT2 and MT3 with a set of EOS to MT3.

 

[GrifterGuru]

Going to be "trying" the 5C kit tomorrow (Wed 11/Dec) to see if I can get on with it. Reason for trying it? I have a set of 20 bolts to machine to identical standard. 5C with a stop "appears" to be the best way to get them identical.

I do have to get the chuck running properly on the backplate as there was some radial runout when I test mounted it, but that should not take too long to resolve.

We will see how it goes.....

***** EDIT TO ADD *****

So I did use the 5C chuck and collet with a collet stop. Made life easier for repeat work.

Still not overly keen on it but I can see the advantages over ER32.

***** EDIT TO ADD *****