Adapting a boring head

[Ironman]

When I bought my boring tool, it came with an R8 shank, and so did my mill. And then I sold the mill and got something more ridgid, and with a CAT40 spindle.
I have no idea if any of you use this type of spindle, but I thought it may be useful, so...

I initially thought meh, I'll just get another spindle adapter, no biggy. And then I went to buy one used and saw the $750 US price tag, and that was 25% of what the head cost.
So I grabbed the adapter and machined the R8 down to a 7/8" shank and put it in a collet chuck.
This worked fine for years, except in the incidences where I had something tall on the table, like a gearbox. and then the whole thing begins to show that it takes up a pile of room.
So I thought it was time to make up something better, and here it is.
I have a collection of CAT40 stuff I bought a while ago just for this very thing, so I grabbed one and machined down and parted off all unnecessary metal and left a register to center the boring head as in the second picture. Then I made a collar that would bolt onto the head and also the adapter. I had thought of tigging this to the cat40 adapter, but as these are heat treated, I did not know what would distort if anything so I screwed it all together.
It now takes up 3 inches less room than it did before.

 

[Dan Dubeau]

Nice job. One can never go wrong reducing tool stickout.

 

[MrWhoopee]

I'm a fan of straight shanks. Short, straight shanks. Shanks that don't require a lot of cranking.

 

[thestelster]

Nice job. I'm coveting your facing/boring head!

I think that adapter is NMTB40, not CAT40. Taper is the same, but CAT40 has a removable pull stud.

 

[Ironman]

Nice job. I'm coveting your facing/boring head!

I think that adapter is NMTB40, not CAT40. Taper is the same, but CAT40 has a removable pull stud.

It could be NMT40, I unscrewed the pull stud because my drawbar goes in that hole. The reason I think it is CAT40 is the mill is European, I have one driving ear removed, as it engages with one and the other interferes, because the spindle is a NMT.
The Narex is a joy to use

 

[thestelster]

That's odd that it had a pull stud inserted into that. Here is a photo of the two styles, CAT40 on the left; NMTB40 on the right.

Also, from Chaski.org:

A 40 taper is standard all the way thru.
What differs is the total length, the collars and driving slots and the draw bar threads and length.
The NMTB which stands for National Machine Tool Builders, has a small parallel diameter at the small end of the taper and is threaded 5/8" UNC.
The BT series is lacking the short parallel piece and is 'usually' threaded M16.
A BT 40 will fit a NMTB40 machine if you replace the drawbar with a longer metric thread one.
The differances between the CAT series and the NST are the way the driving dogs are situated in the collars. Some are offset and some have unequal slots. This is all for the auto tool changers to line the tools in. On a manual machine none of this matters and you can get away with it by either grinding the slots or just removing one drive dog from the face and just driving on the smaller of the two.

 

[Ironman]

I do believe my adapters are threaded in Imperial as the drawbar is. My driving dogs are offset. The adapters look like the one on the right in your picture.
Lagun is marketed in North America out of the USA, and as such may have some changes for the non metric crowd.
I do like the 40 taper as I can stick a finger up there to wipe it clean.

 

[thestelster]

Yeah, the 40 taper is real nice. I use an ER40 collet chuck for the majority of my milling.

But when I want to do some roughhousing like facemilling or endmill roughing, or using the boring head, I take the collet chuck off and use those tools with #40 taper.

I also made a wooden spindle wiper on the lathe with the taper turning attachment. I wrap a sheet of paper towel around it and use it that way. ((Easier than trying to do a Linda Blair (Exorcist) with my finger.))