Make your own?

[Peter Blair]

Hey everyone. I wonder if anyone on this Forum can help me or am I looking in the wrong place?

Instead of purchasing a new system I am considering updating my Elbow system and wonder what would be the best metal for boring bars?

Should I use square stock or round stock?

I am planning to drill holes into and or through the bars to accept typical cutting tools and then tap and thread for allen screws.

I would like to make some sort of standard bar(s) with replaceable ends that would hold straight and angled cutters.

I am assuming the steel has to be pretty hard or would I need to have it hardened after machining?

Any other help/suggestions anyone can provide would be great!

[Dale Miner]

I would use round stock. A square piece has a larger corner to corner dimension that the round stock, and as such, would require a larger opening when getting up under the shoulder. Also, any oops with a square section would damage the opening much worse that a round. The extra strength gained from a square is minimal compared to the increase in corner to corner dimension. A round stock with the same diameter as the corner to corner dimension of a smaller square will be stronger. Since you are going to be using in a captured system, having a flat for the bar to register on is not needed.

There is very little to be gained in having a hardened bar in terms of reducing chatter at the cutting tip. Cold rolled is sufficient.

[Ed Morgano]

Peter,
I used 3/4" round stock (just mild steel from ACE Hardware) with a 1/2" extension for the tool holder. I'll try to post some pictures this evening.