Collet options for MT4 lathe spindle

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SteveM
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Collet options for MT4 lathe spindle

Post by SteveM »

Someone I know is looking at a "South Bend" lathe from Grizzly.

I always found it interesting that on their lathe pages, they will list accessories, but not collets.

Now I think I know why.

Several of their lathes have MT4 spindles.

They do not have a collet sleeve to go from, say, MT4 to 3C or something else.

Yes, there are 4MT collets available, but as they are not self-releasing like 3c, 5c or r8, you'd end up having to bang on them to get them out.

The best option I see is a faceplate collet chuck for ER collets like this:
30062917-4a31-41fd-a67c-aec0dcd0b0ae[1].jpg
Any other ideas?

Grizzly suggested a 4mt to 3mt drill chuck adapter and a 3MT er collet chuck, but that gives you no way to pass stock thru, nor to use a drawbar, so good luck with that.

Steve
John Evans
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Re: Collet options for MT4 lathe spindle

Post by John Evans »

Try "JFK" they may have or can make a MT4 to 5-C adapter . But they are proud of their stuff !
www.chaski.com
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Bill Shields
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Re: Collet options for MT4 lathe spindle

Post by Bill Shields »

but -> doesn't a 5C collet require a 5MT (or at least a 4.5 MT which is what my old SB lathes have) ????
Too many things going on to bother listing them.
SteveM
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Re: Collet options for MT4 lathe spindle

Post by SteveM »

Bill Shields wrote: Wed Nov 16, 2022 8:59 am but -> doesn't a 5C collet require a 5MT (or at least a 4.5 MT which is what my old SB lathes have) ????
Correct.

I have a South Bend 5C collet sleeve from a Heavy 10 and the wall thickness is only 0.160", so you might need a negative wall thickness :-)

For a 4C adapter, assuming it was 2-1/2" long (same as my 5C adapter), the wall thickness would be 0.076".

If it was only 2" long, it would be 0.089".

The thickness at the large end would be 0.141"

As the sleeve is tight against the spindle wall, it doesn't need a ton of strength, a 4MT-4C adapter might be do-able.

Steve
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Bill Shields
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Re: Collet options for MT4 lathe spindle

Post by Bill Shields »

whew...thought I was losing what remains of my functioning brain cells
Too many things going on to bother listing them.
SteveM
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Re: Collet options for MT4 lathe spindle

Post by SteveM »

Bill Shields wrote: Wed Nov 16, 2022 2:36 pm whew...thought I was losing what remains of my functioning brain cells
We are.

Just not the part that does collets. :-)

Steve
jcfx
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Re: Collet options for MT4 lathe spindle

Post by jcfx »

SteveM,

There are also 5c scroll type chucks, depending on the ER series # he would be limited in gripping sizes.
this Bison one is an example, price and quality goes downhill from there ;) -
https://bison-america.com/produkt-26828-3911.html
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NP317
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Re: Collet options for MT4 lathe spindle

Post by NP317 »

Get the Bison.
Mine has been serving me wonderfully.
I just put it back on the lathe this afternoon for some square brass stock turning.
RussN
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Bill Shields
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Re: Collet options for MT4 lathe spindle

Post by Bill Shields »

They are a solid reputable product that has been around for decades.
Too many things going on to bother listing them.
Richard_W
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Re: Collet options for MT4 lathe spindle

Post by Richard_W »

Unless you have a power draw bar for an R8 you often have to tap the draw bolt to release the collet.
SteveM
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Re: Collet options for MT4 lathe spindle

Post by SteveM »

I have a non-Bison one of those 5C collet chucks.

I have to make a backplate for it to use it on my South Bend 9A.

For up to 1/2", I have 3C collets, but I can use this for above 1/2", although I don't know how precise and repeatable this one is.

Steve
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Bill Shields
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Re: Collet options for MT4 lathe spindle

Post by Bill Shields »

3C on a 9A - question

Mine is 3AT - taper on collet closer nose is different?
Too many things going on to bother listing them.
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