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

HI Dave,

I have a few saw blades from Sherline, what thickness is wanted? The
coupler I have handy has REALLY thin slots. Might be a little tricky to get
the helical cuts made!

Box tubing might work, my first thought was just to use Leadalloy (steel)
rod, and thread both ends. I've drawn up the first mount (X axis) with a
plate and four 3/8" rods. The couplers were more expensive then I figured.
As discussed, I think I can make what I need. Two slotted rods (across end)
with bore and setscrew for the shafts, and a Delrin disk with two
perpendicular blades to engage the slots on either side of the disk.

I went so far (a few years ago) as to draw up the Sherline CNC motor mounts,
thinking I might want to machine my own. WAY TOO MUCH work! It wouldn't be
the best match for this project anyway. AND, the helical couplers and two
loaded bearing setup wouldn't work with MY lead screws.

I have room for a single bearing, it looks like. I'll probably use a single
flanged bearing, and clamp it in on the X (main ways). For the Y, the lead
screws I have are made to be held in compression by a bearing at each end
(pair of linear guides and ball-bearing linear bushings in the set).

For Z, I'm not quite designed yet. Looks like I get a bearing on each end
as well. I'm going to have to precision drill for two linear bushings and a
lead screw nut in two directions through a block of aluminum for the Y-Z
translation. It should be possible with good accuracy on the Sherline mill.
We'll see!

I just ordered some linear bushings and precision shaft from VXB!

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

>
>
> You can make your own helical coupling from aluminum and a jewelers
> saw. just make a small ficture to hold the blade on your lathe and
> then another to hold the part on the cross slide.
>
> really neat is that when you get the saw moving at a nice slow speed,
> the cutting oil is wrung to the outside, but does not fly off.
>
> As for the mount, you can make them in a few ways.
>
> one is to use box tubing. cut it for the stand off and then make
> plates to attach it.
>
> or, you can take 3/4" bar and drill and tap it on both ends and mount
> plates to that.
>
> Dave
>
>