I've been searching for a second hand boring and facing head for a while now, but haven't been able to find one cheap enough, so last week, I treated myself to a metric boring head, but a small one, 40mm diameter. I have plans for it, so I didn't want a 50mm one to match my Imperial boring head
The problem is that although it comes with an MT2, MT3 & parallel shanks, I use R8 on my mill. So at the same time, I bought a blank R8 arbor.
So this post is just to show the unitiated how I go about machining it up to fit.
![](http://i202.photobucket.com/albums/aa102/bogstandard_photos/From%20June2010/Borehead01.jpg)
The R8 arbor is a little difficult to hold rigid enough in a lathe chuck, and because it already had a centre drilled into the end, I set it up between my chuck and a live centre.
![](http://i202.photobucket.com/albums/aa102/bogstandard_photos/From%20June2010/Borehead02.jpg)
It was soon down to rough size, but because I was getting tight on the live centre, I swapped it for the old standby, a solid half centre with some grease on the end. This allowed me to get real close up
![](http://i202.photobucket.com/albums/aa102/bogstandard_photos/From%20June2010/Borehead03.jpg)
I had already measured the thread required, it was 14mm x 1mm pitch, a thread size that is being used in a few bits of tooling nowadays. So the thread spigot was turned to size, a thread runout slot cut just a little deeper than the thread depth, and the lead in taper put on the end.
![](http://i202.photobucket.com/albums/aa102/bogstandard_photos/From%20June2010/Borehead04.jpg)
It only took a couple of minutes to cut the thread once I had swapped over one change gear, and slipped the selectors into their correct positions. The swing up threading tool did it's great job, just like normal.
![](http://i202.photobucket.com/albums/aa102/bogstandard_photos/From%20June2010/Borehead05.jpg)
The new head fitted really smoothly.
![](http://i202.photobucket.com/albums/aa102/bogstandard_photos/From%20June2010/Borehead06.jpg)
So now I have the set of mandrels so that the head can be used on any of my machines, but I have now got to go find it a home in one of my racks, as it now won't fit back in the box it came in.
![](http://i202.photobucket.com/albums/aa102/bogstandard_photos/From%20June2010/Borehead07.jpg)
A nice easy job to do on a quiet Sunday morning, now I can get stuck into the Minimag build.
Bogs