Will a C5 collet slip without a 'key' pin? How to replace the pin?

[dansawyer]

First question: I have a C5 collet adaptor with a sheered key pin. I can see and feel where the pin was, however it is totaly gone. I would like to test the adaptor, am I safe to do so for a short test without a pin?
Second question: How do I replace the 'pin'. The adaptor is likely hardened. How can a hole be 'made' sufficient to set a replacement? Should I use a press fit on a taper pin? Or is there a better way?
Thanks, Dan

 

[Zack]

Do you mean collet closer rather than adapter? I backed the pin out on my closer. Have never had a problem with it slipping.

 

[dansawyer]

Do you mean collet closer rather than adapter? I backed the pin out on my closer. Have never had a problem with it slipping.

I am not sure of the correct vocabulary. It is a MT 4 1/2 bush that fits in a lathe and holds a C5 collet. The collet itself it held in by a shaft and a lever arm that goes through the spindle from the back. I suspect there is an adjustment in the closing mechansim that would allow for adjusting the tension. (It may be as simple as how far the collet is screwed into the closing mechanism, I am not sure yet how that all works.)
That said, if you have not had an issue with slipping.

 

[Zack]

Yeah, that's called a collet closer. MT 4 1/2, you probablly have a draw bar going through the spindle to tighten the collet up.
Mine doesn't slip. The spindle on my old mill takes Brown and Sharps #9 collets, and they aren't made with a slot for an indexing pin. Never had a problem with them slipping, even with large end mills or a drill chuck. Others may say different but I backed the pin out on my lathe 5C collet closer. One less thing to have to line up.

 

[SLK001]

The pin is probably not hardened (the closer most likely is). The pin originally was probably peened into a hole in the closer, then the excess material filed (or sanded) flush to the closer. If you look closely, you can probably see the hole.

However, a 5C collet fits very tightly when engaged, so I don't know of many operations that would require the index pin. Just leave it out, but make sure that there aren't any remnants of the pin that stick proud of the closer (either interior or exterior).

 

[extropic]

Dan,
You are correct in referring to the part as an adaptor. It is a Morse 4-1/2 to 5C adaptor.
It's part of your collet closer, however a lever type collet closer has many parts. The adaptor is one of the components of the collet closer.

Regarding the pin, The pin should be installed into a through hole so, if part of it is still there, you should be able to see the butt end of the pin exposed. It will be a cylindrical pin. I would remove the remnant by pressing or carefully punching it out. By "out" I mean to push the pin through the wall, into the ID of the adaptor. Remove any burrs and slightly break the sharp edge on the hole at the OD, to facilitate installation of a new pin.

There are those that say you don't need the pin. I prefer to rely on the intent of the original designers and would replace a missing or damaged pin.
I think the pin is there only to index the collet and resist spinning while the draw tube is being threaded on and adjusted.

I would replace the pin with a nominal 1/8" (.1251-.1253) alloy steel pin. Buy a pin at least 1/2" in length so you have something to hold onto.
Usually the pins come with domed or tapered ends. You want to grind off one end of the pin until it is square (not domed or tapered). Break the sharp edge with a diamond file or the like. Make certain there are no burrs. Any burrs will interfere with installation. Press the flattened end through the wall of the adaptor until it protrudes .045-.050" into the ID. Longer protrusion will hang on some collets. After the pin is installed to the proper depth, grind off any portion of the pin protruding from the OD of the adaptor. A small mark where a grinding wheel hits the OD of the adaptor is of no significance. Just be sure the pin doesn't protrude from the OD.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[dansawyer]

The pin is probably not hardened (the closer most likely is). The pin originally was probably peened into a hole in the closer, then the excess material filed (or sanded) flush to the closer. If you look closely, you can probably see the hole.

However, a 5C collet fits very tightly when engaged, so I don't know of many operations that would require the index pin. Just leave it out, but make sure that there aren't any remnants of the pin that stick proud of the closer (either interior or exterior).

Yes, I can see the pin. I would be concerned about driving it out directly against the closer. However if there were a light press fit support with a relief hole is the best thing to press the remainder of the pin out?

 

[MrWhoopee]

Much like an R8 collet, the pin on a 5C is more to prevent spinning while tightening than it is to drive the collet once tightened.

I suspect there is an adjustment in the closing mechansim that would allow for adjusting the tension. (It may be as simple as how far the collet is screwed into the closing mechanism,

Yes, it is as simple as how far the collet is screwed into the draw-tube. Screw it in until the collet clamps firmly when the lever is pushed back. The lever should "snap" as the collet is closed. If you can't get it to snap, you've tightened too much.

 

[dansawyer]

Dan,
You are correct in referring to the part as an adaptor. It is a Morse 4-1/2 to 5C adaptor.
It's part of your collet closer, however a lever type collet closer has many parts. The adaptor is one of the components of the collet closer.

Regarding the pin, The pin should be installed into a through hole so, if part of it is still there, you should be able to see the butt end of the pin exposed. It will be a cylindrical pin. I would remove the remnant by pressing or carefully punching it out.

There are those that say you don't need the pin. I prefer to rely on the intent of the original designers and would replace a missing or damaged pin.
I think the pin is there only to index the collet and resist spinning while the draw tube is being threaded on and adjusted.

I would replace the pin with a nominal 1/8" (.1251-.1253) alloy steel pin. buy a pin at least 1/2" in length so you have something to hold onto.
Usually the pins come with domed or tapered ends. You want to grind off one end of the pin until it is square (not domed or tapered). Break the sharp edge with a diamond file or the like. Make certain there are no burrs. Any burrs will interfere with installation. Press the flattened end through the wall of the adaptor until it protrudes .045-.050" into the ID. Longer protrusion will hang on some collets. After the pin is installed to the proper depth, grind off any portion of the pin protruding from the OD of the adaptor. A small mark where a grinding wheel hits the OD of the adaptor is of no significance. Just be sure the pin doesn't protrude from the OD.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Thank you. This is very helpful. I will plan to follow it. Again, thank you. Dan

 

[SLK001]

Yes, I can see the pin. I would be concerned about driving it out directly against the closer. However if there were a light press fit support with a relief hole is the best thing to press the remainder of the pin out?

I would drill a hole thru the center of the remaining pin, then press it out.

Here's a pic of a South Bend index pin: