Boring out collets

[krhoover]

You guys are going to tell me that I need to smoke another one but, could a 1/2 collet for an old round ram m head be bored out to accept 5/8 end mills? I was given several and would like to be able to use them in my old mill.
thanks

 

[L Vanice]

The 2MT or 7B&S collets used in the M heads both have a maximum order hole of 1/2 inch, so you would not get very far enlarging the bore to 5/8 inch. You might look for a 5/8" endmill holder or ER collet chuck with whatever shank you need. Watch out for metric drawbar threads on most import tooling.

Larry

 

[krhoover]

What do you mean by a 5/8 end mill holder. I thought the largest off the shelf collet was 1/2. Kinda new at this stuff.

 

[neanderthal mach]

You haven't mentioned your mills spindle taper so this is just a generic example of end mill holders. https://www.amazon.ca/HHIP-3900-1005-5-piece-Mill-Holder/dp/B00QVYTQFE?th=1 They do require what's generally known as a Weldon shank with a flat machined on the tool shank of the end mill for the set screws in the sides of the end mill holders to tighten against. A bit of an old school method today but they work just fine.

 

[krhoover]

You haven't mentioned your mills spindle taper so this is just a generic example of end mill holders. https://www.amazon.ca/HHIP-3900-1005-5-piece-Mill-Holder/dp/B00QVYTQFE?th=1 They do require what's generally known as a Weldon shank with a flat machined on the tool shank of the end mill for the set screws in the sides of the end mill holders to tighten against. A bit of an old school method today but they work just fine.

It's a b&s #7 taper. I know that's not the most popular out there.

 

[krhoover]

It's a b&s #7 taper. I know that's not the most popular out there.

The next question would be, how about having shanks of end mills turned down somehow to 1/2 ", I know there probally awful hard, but needed to ask.

 

[neanderthal mach]

Yep afaik the #7 is today even less common than the B&S # 9 so it might be tough to find anything in that #7 taper. There are "some" reduced shank end mills around. But that's still a work around. I dunno, if it were me I think I might eat what it's going to cost and have an ER 32 or 40 collet chuck shank reground to your B&S #7 and add a custom draw bar threaded for whatever female thread is in the ER collet chuck you'd be using. Find the dimensions for that B&S #7 then find a ER collet chuck with larger dimensions than that to have it reground. Just be sure your spindle through hole will still clear whatever draw bar thread is in that collet chuck.

 

[L Vanice]

Travers has endmill holders in both 7 B&S and 2 MT. The good news is that they both have 3/8-16 drawbar threads, same as Hardinge collets. The M head should have that size drawbar. The catch is that the 7 B&S largest bore is 1/2" and the 2 MT largest is 5/8".

2019 Master Catalog - Travers Tool —Page 848

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catalog.travers.com

You could check other suppliers now that you know what to look for. WT has the 7 B&S-5/8", but they do not tell the thread size. You do not want to deal with metric drawbar threads in your 7 B&S tooling.

5/8" Bore 7 MT B&S Brown & Sharpe Taper Threaded for Drawbar Style B End Mill Holder

Over 60 years in the business, with warehouses located in Warren, Michigan and Tulsa, Oklahoma. Place your order now via phone, fax, or the web at www.wttool.

www.wttool.com

Larry

 

[krhoover]

I didn't think it would be easy, thanks all.

 

[MilGunsmith]

There are a couple of B&S7 to ER-32 collet chucks on Amazon. Probably available from other sources. Years ago I made a B&S7 to ER-20 collet chuck for my M head. You lose some work capacity, but it was better than trying to find collets at the time.

 

[krhoover]

Thanks, will look into it.

 

[rons]

could a 1/2 collet for an old round ram m head be bored out to accept 5/8 end mills? I was given several and would like to be able to use them in my old mill.

I think the cost of a 5/8 collet is not worth the trouble.

 

[krhoover]

But they look so shiny, haha