Boring Head

[chrism_75006]

Howdy all! I bought a Sherline machine shop package last year and just recently had an opportunity to use the boring head on my mill. Of everything that I've done so far, I am not happy with their boring head. I found a thread here where someone listed out a bunch of accessories that were suggested and I can't find it to post this question there. Someone suggested a Criterion head (2"???) as being better than Sherlines. My question is how do you attach it to the mill? I believe that the options are a #2 MT, #3 MT, or 1/2" straight shaft. The Sherline has a #1MT. Using a collet it can go up to a 1/4" shaft or 3/8" using a drill chuck. Suggestions? Do you have to make an adaptor or does someone make a #1 MT arbor? Thanks!!!

 

[Downunder Bob]

Hi, you don't say what model mill you have, but from the dimensions you give, such as MT1, 1/4" shaft and 3/8 drill chuck, I suspect its rather small.

Forget the drill chuck most chucks are not good enough to hold milling heads or cutters even directly.

Does the boring head have a thread on the back such that you can attach different arbours , as in MT1, MT 2 etc, or R 8 for the bigger mills. Make sure that the arbour you get also has a thread in the back for a draw bar you will need to use a draw bar to securely hold the boring head in the spindle.

 

[mikey]

Welcome to HM, chrism.

I own a Sherline 5400 and have recommended a Criterion S 1-1/2 boring head to other Sherline owners. It is vastly more rigid and accurate when compared to the Sherline boring head. This head has a 7/8-20 thread on the top of the head. LMS and A2Z used to sell a 7/8-20 to 3/4-16 adapter that allowed this head to screw right on to the Sherline spindle, making for a very rigid and accurate attachment. I don't know if LMS carries these adapters anymore but you might contact them to find out. A2Z, of course, no longer exists and I think they used to supply LMS.

If you cannot find one, an adapter should not be difficult to make on a lathe. Here is one example that a guy made.

Trust me; the S 1-1/2 is a vastly superior head compared to the Sherline version. Look for the head that takes 3/8" boring bars; the 1/2 bars are too heavy for this head. Because the Sherline mill is so light, centripetal forces are a very big deal and the heavier bars will limit you to low rpms in larger bores. I also recommend you consider cobalt boring bars for this head. They cut much better at lower speeds compared to brazed or inserted carbide.

 

[DoubleHelix]

I have a Criterion DBL-152 that came with a 1/2 straight shank that I got off ebay for a great deal. I machined the 1/2 shank into a MT1 to fit the sherline spindle. Definitely bigger than a S 1-1/2 that mikey uses so you lose some precious Z using the 152.