Re: Semi-good high speed spindle idea? - Proxxon collet chucks

Irby,
how low did you get your runout on your collet mounting ?

In theory, the absolute best result is to machine the end of the
spindle after it is mounted and driven, that way you can reduce the
runout to a virtually unmeasurable amount.. machining it on the lathe
means the least runout you can achieve is the runout on the lathe
chuck. Using the lathe I have not managed to fit the collet chuck with
less than 2 thou runout yet.

One of my next experiments (when I get round to it) will be to

1. cut a cutting edge on the end of the spindle,
2. mount the spindle on the mill in the bearings it will run in,
3. severely preload the bearings to reduce runout to nil.
4. cut a hole using the spindle into a peice of stock mounted on the
table
5. drill the end of the spindle using an 8mm centre drill mounted in
the hole in the stock
6. cut the taper in the end of the shaft using the taper reamer I
made previously. (it is already made from 8mm drill rod)
7. hand cut the thread for the collet nut.

I am hoping I will then have a shaft with indetectable runout at the
collet.

Chris (-=Spiyda=-)



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Irby Jones" <irbyrat@c...>
wrote:

>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Chris Horne" <chris@s...>
> wrote:
> >
> > I actually got mine online in the UK
> >
> > but a google search shows this for the US
> >
> > http://www.woodcraft.com/family.aspx?DeptID=5013&FamilyID=4624
> >
> > The shaft needs an 8 x 0.75 thread
> > the shaft is then bored about 4.75mm
> > then the end has to be accurately countersunk at approx 30 degrees
> >
> > I made a machine reamer from drill rod to do this part
> >
> > I then Air hardened and oven tempered mine
> >
> > it seems a bit of a performance but I reckon it's worth it..
> >
> > the alternative would be to buy the cheapest hand tool with the
> chuck
> > on it and salvage the shaft for fitting to your own shaft.
> >
> > If anyone has a CNC lathe, it might be worth making up some shafts
> for
> > resale.. I only have a manual lathe and I'm in the UK so I don't
> > think it would be cost effective me offering to make them. At around
> > 30 minutes each I would have to charge more than it would be worth !
> >
> > Chris
>
>
> I am using the Proxxon collets too. They have a much lower runout
> than the other cheaper grinders. I made a new "spindle" for them,
> pretty much the same as Chris, and it works just fine. I did cut the
> inside diameter and taper with a 1/8" carbide ball end mill in the
> lathe toolpost grinder to reduce the runout as much as possible. I'm
> going to make another spindle like this soon since it works so well.
>
> The local Woodcraft store had the collet set, the chuck and also the
> flexible shaft handset. I got the handset to try out because it was
> about half the cost of the grinder itself, and appeared to have an
> identical spindle. One word of caution in using the flexible shaft
> handset, though. They are not intended to be used for hours at a time
> as a cnc router requires, and mine got hot enough to melt the outer
> plastic covering. That ruined it since the covering gives the cable a
> lot of support. No problem in my case, as I just cut off the cable
> and used the little handset by itself. I left enough of the inner
> cable to attach to a drive motor. I put a picture of the
> new "spindle" here if you want to see it:
> http://www.metalworking.com/DropBox/Proxxon_collet_adapter.txt
>
> Irby
>