Arch wrote:
Rough hollowing and cleaning out large end grain blanks is getting to be
more chore than fun. Even with two toolrests and a cobbled up
restraining device, my armbrace and long 3/4" boring bar is getting
heavier by the day and I'm running out of aspirin. Still I don't want to
buy an expensive large hollowing system.
Very large expansion bits are expensive and limited in use so drilling
out large amounts of waste isn't feasible, but would machine boring be.
I see by the latest HF flyer that they have a cross slide with vise on
sale for $30.00. travel cross 5 3/4", longitudinal 6 3/4" , overall
ht. 6", wt. 32 lbs. It's probably very sloppy and bulky, but with a
cobbled easily moved bed clamp and packing to center the boring bits and
maybe an added shopmade swivel, that shouldn't matter. Or should it?
Of course I'd have to drill a hole for the boring bar and form and
finish the interior walls after the rough hollowing and I probably would
need a wide entry. Also there would be a lot of cranking and moving the
cross slide. If the idea was any good, I reckon everybody would be
boring out the bulk of their hollow forms.
This is all from my armchair with no actual experience other than boring
metal, which isn't comparable. Before I buy the cross slide just to add
to my stable of workable but impractical HF 'adaptions' such as tailpipe
expander pin chucks, venturi vacuum systems, black iron pipe do-dads
etc. etc., some questions:
1. Would boring like machinist do, work? 2. Would it be easier to use
and less strain on my arms & shoulders than the armbrace? 3. Anybody
doing this?
4, Your general opinion, cautions, etc. Don't spare me 
5. A simple better way other than sending me to the turning accessory
suppliers.
Turn to Safety, Arch
Fortiter
http://community.webtv.net/almcc/MacsMusings
I generally use Forstner bits for items other than bowls. If I need a 4"
hole I start with a 4" bit just deep enough to get a guide hole, maybe
1/4 inch. It is slow. Then I change to a 3 inch bit and do the same,
then 2 inch, etc. The smallest size is driven to the calculated depth
then the next smallest. When I get back to the largest bit it doesn't
have to remove as much material and goes right in. Making a stepped cone
hole like this allows the bit to reach farther on the smaller bit
because there is room for the entire bit and most of the chuck. Just
watch the chuck closely on backing out. I once pulled the jacobs chuck
off its taper while backing out and such a racket it made as the turning
blank held the bit and slung the chuck around against the ways. A real
poor man's stress test.
--
Gerald Ross
Cochran, GA
A good scare is worth more to a man
than good advice.
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