Author Topic: Small Boring head, required features  (Read 3111 times)

Offline bp

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Small Boring head, required features
« on: August 06, 2013, 08:28:01 AM »
I've just finished boring a 34.7mm diameter hole through some 26mm thick free cutting steel.  This was such an exciting task that I started to think about the features that make a good boring head.  I know that there are lots of designs by smart people but I rather want to have a go at my own, at least designing it.
Broadly, my known requirements are
1/  Usable on my Sieg X2 mill with an MT3 spindle
2/  Have a range up to (say) 40mm diameter with a vertical tool (pre-supposing that "conventional" layout is used)
3/  If built at all, to be built on my X2 mill and C3 lathe

So, it seems to me that the requirements are
1/  Rigidity
2/  Smooth and accurate changes of diameter
3/  Rigid toolholding
4/  As short in "Z" as possible

Anyone got any comments? 
Or should I just go and buy a good one, if so what?

Offline chipenter

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Re: Small Boring head, required features
« Reply #1 on: August 06, 2013, 09:04:10 AM »
I made mine from a blank end arbor , cuts out making the morse taper .

Offline PeterE

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Re: Small Boring head, required features
« Reply #2 on: August 06, 2013, 10:06:35 AM »
I am currently making a GHT boring head according to the drawings in his book Model Engineers Workshop Manual. I am right now waiting for an M6x0.5 mm tap and plan to screw-cut the feed screw with the mating thread. That way one turn on the dividing head makes 1 mm on the diameter of the bore. makes for simple maths I think.

I have an SX1L mill, that is one number smaller than yours bp. Normally I have a 2MT to ER32 head in the spindle so I made a plain 12 mm stem for my boring head.

Oh yes, if you think this head is useful, a material kit is available from Hemingway in the UK.


Always at the edge of my abilities, too often beyond ;-)