On Sun, 15 Jun 2003 18:58:14 +1000, adam Seychell
<
adam_seychell@...> wrote:
>
>
> Russell Shaw wrote:
>> I haven't got a motor yet. I was thinking of using a cheapy
>> motor to drive my own shaft with lower slop bearings.
>
> Lowest cost I've seen would be something like the trimmers/die grinders
> you were looking at. That's the first time I've heard of trimmers. The
> trimmers seem more suited because they have better mounting assembly
> attached to them. The die grinders are designed to be held by hand. The
> die grinder I got has a round part on the end for mounting. Stefan
> mentioned a Proxxon was also a very well made motor, but don't know who
> sells them in Australia. The Bosch GSS27 I got was about AUD$240, I'd
> expect all these motors to be around the same price range (AUD$240 ~
> $340). The AUD$100 Dremal kit would be a complete waste of money for a
> cnc. These are all industrial type tools, so you may not find them next
> to handyman stuff.
>
>
∗∗∗∗ 1) motor:
yes the proxxon ibe "bohrschleifer" is a good device (eur 100).
they have also a english page i think.
it was also not so easy to get for me.
i asked the local importer of this proxxon tools for a shop where i can go
and see it.
they sent me a xls list with a lot of shops.
i selected two closer together in vienna and went there.
the first has had the ibe at display, but has no units to sell there.
but i could look at it and liked it.
i went to the second shop and they also hadn't it there. but the owner made
much more effort to sell it and ordered
it for me (the one of the other shop didn't even ask). so i bought it
there.
it took 2 weeks to deliver it to them.
i think the most important two things are:
a) a good bearing. the really cheap devices only put a short shaft with a
thread on a standard motor.
thus only using the bearings of the motor. please make your own opinion on
that ;-).
b) PRECISION work of shaft and collars.
the cheap grinders i have here are all no precision work.
the bit is not centered very good, thus it will break more easily.
the proxxon precision is fascinating.
the collars are very strong material (hardened - very springy).
they are ground very exactly, also the shaft is ground.
they are shaped so that they are always centered.
proxxon knows this, they advertise this a lot....
i have inspected other tools (dremel etc) at the stores here also.
they have even aluminium collars, far from precision..
i have not seen the bosch grinder.. they had it in one shop but it is twice
the price of the proxxon..
i also think the thick throat is no help in using it (the proxxon has a
longer narrower).
for me it looks like a chopped of angle grinder ;-).
but sure for pcb it would be fine too.
(the disadvantage of powerful motors (more than 100 watts) would be
noise... you don't need much power in pcm drilling)
∗∗∗ 2) adams new press:
hey adam what are you doing?
i really thought you are telling me for weeks now that a triangular arm
would be better.
i thought of placing the back bearing on the two outer edges. this should
prevent the unit
from sideways clearance at the front.
i thought this because your first unit needed a guidance bearing in the
middle of the arm to stabilize.
it there no clearng with the new tapered bearings??
maybe i will try it anyways with the thrust bearings and triangular setup.
i found two of them finally now when i searched for tapered roller bearings
;-).
i had them at home all the time.....
maybe it would get even more stable if i add two normal ball bearings on
the sides...
so each direction is blocked from any slight clearance.
have you tested it already?
is the lenght of the arm still no problem? (difference between tangent
movement and straight)
regards
stefan
sorry for long post but much trouble here with operating system so i had a
longer time off..