Mystery Collets

[shenion]

I picked up a machinist toolbox full of drill bits an end mills. These collets were included and I would like to know what they are for.

They are 3/4 in diameter with no taper. My guess they are reducing collets for a larger collet.

Anyone recognize them, let me know.

 

[scott0031]

Is there anything inside that can be screwed in to allow them to expand so they will grip in a bore. Not ones i have ever seen, but there is a lot of specialised gear out there made for a specific jobs and applications.


Kind regards,


Scott

 

[shenion]

No internal threads or set screw.

Just examined the set; there are 7. They are marked 1/4, 5/16, 3/8, 1/2 and 5/8".

Th smaller ones match the hole size. 1/2 is close to 3/8. 5/8 is just under 1/2.

 

[shenion]

Ok, looking carefully, the bottom inside is square. So their use is now apparent:



That is a 1/2-20 TAP in the collet marked 1/2"

So, must be tap holders to go in a standard 3/4" collet.

 

[scott0031]

Yep and the recess in the front is probably for the spring clip in the tapping head. It will probably be tension and compression type i would think. There are several different types out there and many are country specific brands, so are not familiar in other parts of the world.

Glad you found the answer.


Kind regards,


Scott

 

[shenion]

A bit more searcing and found they are #3 size collets for a Procunier tap head.

 

[scott0031]

Have you got any links? I'm looking for one for my new machining centre on a BT 40 or parallel shank. It's not a brand i have heard of if they are available in the uk.


Kind regards,

Scott

 

[shenion]

MSC Industrial Supply carries them.

Take a stiff drink before you check the price

Here is their main page. They look to be more for high-production setups.

 

[scott0031]

Wow! What is that thing made of diamonds? Mind you the spec is a bit heavy


Tapping Heads | Shank Type: Taper Shank | Taper Size: MT2 | Maximum Aluminum Tap Capacity (Inch): 1-1/8 | Maximum Aluminum Tap Capacity (mm): M27 | Maximum Mild Steel Tap Capacity (Inch): 1 | Maximum Mild Steel Tap Capacity (mm): M24

A big ask for a 2 mt though.


Big capacity plus that is a reversing cone clutch one, so no reversing of the spindle.


I think i will look else where as i only need a simple tension and compression one being as the machine has ridged tapping.


Thanks all the same.


Kind regards,

Scott