Using a boring head

[Eric CoxParticipant @ericcox50497]

[Eric CoxParticipant @ericcox50497]

In the not too distant future I will be purchasing a boring head for my Warco mill.

As an example for a 1 1/2" bore in mild steel, what depth of cut should I take and at what spindle speed.

Assuming I'm roughing out not finishing.

Edited By Eric Cox on 26/10/2016 11:48:22

[BazyleParticipant @bazyle]

Just think of it like a lathe turning a bar but 'inside out' and using a rather long tool sticking out from the tool post more than usual. So you calculate the speed for the appropriate sfm for the material or look it up on a chart for diameter. And depth of cut appropriate to the thin wobbly tool. However don't be too timid and make sure you are feeding it down fast enough not to end up rubbing. This is the equivalent of the automatic feed rate you set on your lathe so wants to be in the range 10 down to 1 thou per rev.

[JasonBModerator @jasonb]

You will often find that speed is dictated by how out of balance teh boring head is, in some positions you can run quite fast others you will need to keep the speed down as a light hobby mill may start dancing across the bench.

[MuzzerParticipant @muzzer]

I suspect you will find out by trial and error that the limitation is often rigidity, aka judder. If you want a decent finish, even with a razor sharp boring bar you may be limited by the realities of a necessarily large overhang and a relatively compliant body. As Bayzle says you also need to take a decent cut. So minimising overhang and using a sturdy, short boring bar are key. Note that adjustable heads can be tightened up between adjustments.

[Tony Pratt 1Participant @tonypratt1]

JasonB & Muzzer are spot on, you can calculate the theoretical figures but in the end how the tool cuts & the machine performs is the best guide.

Tony

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