Shell Mill Arbor Sizes?

[RonRock]

Is there a "chart" or some type of spec sheet with the size and dimensions available for shell mill arbors? I have a indexable shell mill that has no arbor. It seems to be metric. I need an R8 or a 3/4" shank to use in my Bridgeport.

I've Googled and looked at a lot of different arbors some give dimensions, not all. Seems to me that there must be a "standard" but I can not find it.

 

[brino]

My 30th edition of Machinery's Handbook has a table in the "Milling Cutters" section, page 852, but only imperial dimensions.

I'll keep looking.......

-brino

 

[andrewgr]

There's another (potential) variable: the width of the keyway, if present. I have no idea how standardized this is, whether a given diameter always has the same keyway or not. Looking in the McMaster-Carr catalog for facing/shell mill arbors, I see at least 5 different sized keyways-- but again, I don't know if it's standardized or not.

 

[C-Bag]

What is the ID of the shell mill? That seems to dictate the size arbor. Personally I’d get an r8 arbor as it‘s not going to pull out like a 3/4” shank might.

 

[brino]

There's another (potential) variable: the width of the keyway, if present. I have no idea how standardized this is, whether a given diameter always has the same keyway or not.

From the Machinery's Handbook table, the key-ways are standard.

For example,
a 1-1/2" OD shell mill requires a 1/2" arbour, and the key way is 1/4" wide and 5/32" deep.
a 2" OD shell mill requires a 3/4" arbour, and the key way is 5/16" wide and 3/16" deep.

There does NOT seem to be a table for metric arbours in the book.

Also, from what I see at suppliers, they are all imperial sizes:
https://www.mscdirect.com/product/details/08454290?rItem=08454290
https://www.kbctools.ca/itemdetail/?itemCode=7-060-030
https://littlemachineshop.com/products/product_view.php?ProductID=4805&category=

-brino

 

[Jim F]

I have a HSS shell mill, not an insert one.
The R8 arbor has 2 different keys, the shell only fits on one way.

 

[RonRock]

Thanks guys for the discussion. Sorry I have been distracted, but still trying to figure this out.

So in my research I found a Ebay seller that lists several Shell Mill Arbors. He has a selection list, but not much in how to choose. He does list SAE as well as Metric Arbors.
Here is the Ebay link ,

R8 FMB22/R8 FMB27/R8 FMB32/R8 FMB40 Collet Chuck Shell End Mill Arbor Drawbar | eBay

Find many great new & used options and get the best deals for R8 FMB22/R8 FMB27/R8 FMB32/R8 FMB40 Collet Chuck Shell End Mill Arbor Drawbar at the best online prices at eBay! Free shipping for many products!

www.ebay.com

In his description he lists,

R8-FMB22-7/16
R8-FMB22-M12
R8-FMB27-7/16
R8-FMB27-M12
R8-FMB32-7/16
R8-FMB32-M12
R8-FMB40-7/16
R8-FMB40-M12

So now I still have to pick one. They are not cheap enough to buy them all, and come from Asia so slow shipping. No returns.

Edit, before even posting. Took another look maybe the SAE and Metric difference is the thread size of the drawbar. Still several sizes to choose from.

Hard to measure my Shell Mill diameter it has 5 inserts so can't get a good measurement. But with my calipers it measures 39.28 plus or minus from one cutter edge to opposite side. So likely 40 mm is closest. But that could also be 1.546 inch plus or minus.

 

[RonRock]

OK found one more,

8.35US $ 4% OFF|R8 FMB22 FMB27 FMB32 FMB40 M12 7/16 face mill cutter arbor, drawbar thread: 7/16 M12|Tool Holder| - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

They have a chart that shows their dimensions. The smallest is the FMB22 7/16. The critical dimension I see from their chart is D1- 22mm. My Shell Mill measures 16mm. Their D dimension is 41 mm, mine measures 36.3 plus or minus. Considerably smaller.

So now I am back at having no idea what one I need. My last post I thought that the cutter diameter must be how they size the arbor. Now I see that the size of the D1 (shaft) of an FMB22 is 22 mm, an FMB 32 is 32 mm. So Do I need to look for an FMB 16? Starting to seem that way.

 

[Flyinfool]

While the shell may measure .629, the arbor might be .625. A bit bigger clearance than I would expect but its close????
The arbor does have to be smaller than the bore of the shell.