RE: [CAD_CAM_EDM_DRO] Re: flexible couplings for PCB router - spindle

HI Dave,

I have a few Pitman motors, might be able to use one of them. These roller
skate bearings offered for CNC have been said to be good for high speed. I
suppose one just needs a long bore for a couple of these bearings, loaded to
reduce any play.

I have been checking trim routers, and it seems one can get a DeWalt DW670
trim router for about $100 USD. A little big, but I think I can mount one
on the Z carriage I'm designing. Porter Cable 7310 might be another one. I
have a quote coming for the Kress, but I expect it to be EXPENSIVE.

Thanks for the notes on making the helical coupler; it's about what I
guessed. I haven't tried to make one yet. I might want to try an Oldham
first, as it will make assembly easier (and perhaps easier to make).
They're both about $20+ in McMaster Carr for the size I want. My alignment
should be quite close, I may just bore a solid coupler first, until I get
the fittings all right. Then I can make flex couplers if needed (3 axes!).

Alan KM6VV

>
> > What I'm looking for now is the 900 Watt (1-1/4 HP) Kress Spindle. I do
> > have two Dremels to play with (and a ready-made mount) first. I
> wanted a
> > CNConabudget spindle, but I'm told they are no longer offered.
> >
> > Alan KM6VV
> >
>
>
> The CNConABudget spindle is pretty simple, but the one flaw is the
> motor. it has bronze bushings and not roller bearings.
>
> If you can power up one of those RC car motors, 9.6 VDC, you can use a
> brushed motor. The things gobble amps, so you need a really beefy
> power supply.
>
> If you can grab a 1" dia spindle like the CNConAbudge, I have plans
> for one that requires a mill and a lathe. not that hard to make.
>
>
> As for the coupling, the main points are that you can offer flex and
> ridigity.
>
> Since I assume you will be darn close to dead on, you don't need to
> worry too much about how you make the coupling.
>
> The coupling material needs to be considdered. it needs to be able to
> flex continuously.
>
> If you take your part, bore and ream it, put in the setscrews and then
> slice it top and bottom, leaving one connecting section in the middle,
> the connecting section would need to be smaller than the bore.
>
> Preferrable a plunge cut to the center and not a slicing cut.
>
> then repeat on the opposite side to leave a web.
>
> then move the part down the table and rotate it 90 deg. and repeat.
> the material left between the two cuts is the part that will flex.
> repeat that a few times and you're set for a coupling.
>
> put it on your bench, and put your indicator on it and add some
> weight. the weight at which it moves is the force it will give under
> in the machine.
>
> I'll make a sketch and put it in the files section.
>
> Dave
>
>