r-8 right-angle drilling attachment

[norvil1]

do any of you guy's know where i might be able to find a new or used right-angle drilling attachment to fit my r-8 spindle on my tormach? i need to drill some long pieces parallel to the bed.

[Art Pentz]

Hi Norvil1

I adapted a Bridgeport style unit manufactured by H&R Manufacturing for use on my Tormach. I wanted a USA made tool which narrowed it down to H&R and Dorian Tool.


http://www.hrmfg.com/custom/cart/edit.asp?p=96524


Since the spindle nose on the Tormach is the same diameter as a Bridgeport quill (thanks Tormach!), the attachment will fit, but the lack of a quill means you will have to grip the attachment on the limited amount of "nose" provided on the Tormach.

Inspection of the drawings for each manufacturer revealed that the H&R unit had the best internal profile for gripping the Tormach nose. I also liked the use of tapered roller bearings on the H&R model as opposed to angular contact bearings on the Dorian unit.

I had to remove the attachments' R-8 spindle to shorten it and turn down the diameter to allow it to be gripped in a 7/8" R-8 collet. This is necessary because the Bridgeport right angle attachments "expect" to grip the whole length of the Bridgeport quill - allowing the R-8 spindle to mate w/ the taper on the mill.

This modification process is quite easy and takes an hour or so if you have a lathe. Dissassembly requires a snap ring plier - that's it!

I was a bit horrified to discover that, when tightening the draw bolt on the right angle attachment (RAA), all the force is transmitted through the bevel gear to the (locked) Tormach spindle. The size of the RAA gear assembly is small and dosen't look as though it would withstand agressive torque. The manufacturer claims that this has never been a problem - but....

Since I like my R-8 draw bars TIGHT, I modified the RAA by drilling two holes in the face of the RAA where the R-8 collet is inserted - which allows me to use a simple face pin spanner to hold the spindle while tightening the draw bolt (actually a SHCS). The probe on the Tormach made the hole location easy.

I have used the RAA for slitting saws and limited milling with very good results. This adds a lot of functionality to my machine. It takes about two minutes to install or dismount the RAA when I need it. Be sure and remember to reverse the spindle direction as the RAA changes the rotation of the tool.

I have the Tormach spindle (VFD) upgrade and the whole thing works great for slow speed sawing operations. I was concerned about the extra weight of the RAA on the Z axis - so I did some testing before purchasing the RAA. The Tormach handles the attachment w/ ease - a testament to the robust design of the Tormach.

There are import versions of the RAA which are CONSIDERABLY cheaper than the US made units. These may work fine.

Feel free to email me if you have questions or comments.

Best regards;

Art Pentz

[Freddy Bastard]

That would be cool if you could post some pics or videos of your setup. Look's like a very good idea!