a) It is a joystick, right? And the pin (roll or dowel) will be in
shear only if someone is pulling up on the ball, right? Assume
the heaviest guy is say 300 pounds (as anyone heavier would
probably not be able to lift his own weight with even a
two-handed pull-up, let alone with a single-handed one.
Personally, I think that he could not shear the pin without
first breaking something else, such as the mounting of the whole
assembly.
Pull-up force woul dbe transmitted to the following components in
order: Ball-knob - Threaded Shaft - Pin - Shaft Sleeve - Center
Plate - Ball Bearings - Delrin Cups - Top Plate(which will be bolted
to the underside of the control panel).
b) If the whole game weighs 300 pounds, you probably don't *want*
someone to be able to lift it by the joystick ball, so it would
be better to use a pin which *would* shear first to protect the
rest of the machine.
Actually, I don't believe that in the worst case scenario the maximum
pull-up force would reach 30lbs. Even momentarily if an enraged gamer
yanks the joystick upwards.
c) The roll pin will be a spring grade steel, *not* a stainless,
so it would be vulnerable to corrosion anyway. (So would the
dowel pin, for that matter.) *Except* that it is not out where
it can be handled, and unless someone is going to be pouring
pints of sweat down the shaft, I see no problem.
I just did a redesign that would allow the pin to protrude if
necessary.
I see deburring bits and simular in the Dremel catalog. The various
Dremel tools have different bits for different operations on wood,
plastic, and metal(including stainless). I'll see if anyone at the
Dremel forum has any ideas.
The main problem is having a steady enough hand to control it as
you use it to open up the jagged slots.
No problem. :-) If it were a problem I could create a template.
O.K. I think that I posted that as an example. When you get
your _Machinery's Handbook_, you can look it all up there.
I decided to get the 27th edition:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7010710723 Hopefully
I'll have that this week.
As a firm believer(victim) of Murphy's law I tend to lean towards
getting the best within reason, even it if is over-kill. Hence, my
penchant for "over-manufacturing". :-)
O.K. I would suggest going for cobalt steel bits with split
points, and unless you need the extra length, go for screw machine
length bits. They are shorter, and flex less as a result.
Thanks.
If it comes down to chosing the *right* SFM, I would pick up my
copy of _Machinery's Handbook_ (a recent edition), and look up
what the proper SFM would be for the combination. And I would
then probably use something a bit slower, as these are for
massive production, and are a speed selected to make the optimum
tradeoff between the time the job takes and the life of the
drill bit. And the time taken to change the bit counts for more
than the cost of the bit in this equation. You won't have
production capable machinery, so don't push it.
Ok. Since "time" is a complete non-factor for me, would a 20% drop in
the rated rpm and/or feed rate suffice?
Sure. Maybe even a 50% drop.
Ok. I'll start at half the recommended rpms and work my way up.
You can get quick-change tool holders -- at least for the AXA
size and larger) which have a Morse taper. Get one which matches the
taper in the tailstock -- or adaptor sleeves to reduce if necessary --
and you can mount the tailstock drill chuck in the toolpost, parallel to
the axis of the lathe spindle.
I was looking at an MT2 tool holder. I already eyed an 3MT to 2MT
sleeve to give me flexibility:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7542413378
The major problem with it is that you have to be careful to both
adjust the height of the tool holder (only once), and you have to adjust
the position of the cross slide to be precisely in the middle of the
spindle's axis -- *every* time you go back to that after doing something
else with the lathe.
Perhaps with a 60 degree center reamer the rear of a tool holder can be
shaped to fit the center in the tail stock. Lining up would then be a
matter of backing the tool holder into the tail stock.
BTW. UPS left a nameless notice at my address for three consecutive
days. Now since four of the eight family's in this partcular complex
live at the same address, if there is no name then no one would know
who is supposed to be getting a package. Anyway, I get a card in the
mail UPS stating that they made three attempts to deliver a package
from MSC... I could go on and on about my past problems with UPS(and
the neighborhood driver in particular), but... (Sigh).
This suggests that you need to find a *service* to receive things
for you, because MSC uses UPS for all their shipments which are not too
heavy. I suspect that it was your catalog.
Yes. I had UPS divert it to my job in Manhattan.
(*Huge* catalog with *expensive* tools).
Thanks. :-)
Darren Harris
Staten Island, New York.