[CAD_CAM_EDM_DRO] Re: small spindle ?

While the runout of any spindle should be optimum, that in itself is
insufficient to make a choice. What should be examined is a
side_load/deflection curve, which is hardly ever given.

Regards
Roland

On 9 June 2012 05:37, Jeffrey T. Birt <birt_j@...> wrote:

> **
>
>
> Should have been �below 0.001��
>
> Jeff
>
> From: CAD_CAM_EDM_DRO@yahoogroups.com [mailto:
> CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Jeffrey T. Birt
> Sent: Friday, June 08, 2012 6:36 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: RE: [CAD_CAM_EDM_DRO] Re: small spindle ?
>
>
> Any decent ER11 chuck/collet will have run-out well below 0.0001�. The
> construction of the spindle in question looks to be a smallish DC motor,
> about the size of a battery powered drill, with a modified ER11 collet
> chuck attached to the motor�s shaft. This type of motor is not deigned to
> handle a side load like that. By comparison a spindle or spindle/motor
> (such as used in commercial routers) has much larger bearings that are
> designed for that type of work.
>
> The PreciseBits collets for the Colt come in two flavors, of which the
> lowest grade provides a run-out of less than 0.0006�, the PG grade collets
> are less than 0.0004�. When you move up to the larger router motors the UP
> grade collets can provide a run-out of less than 0.0002�. These
> collets/closing nuts fit right in place of the stock collets and closing
> nut; there is no �mounting� of anything.
>
> Jeff Birt
>
> Soigeneris.com
>
> From: CAD_CAM_EDM_DRO@yahoogroups.com <mailto:
> CAD_CAM_EDM_DRO%40yahoogroups.com> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com<mailto:
> CAD_CAM_EDM_DRO%40yahoogroups.com> ] On Behalf Of Larry Guthrie
>
> Sent: Friday, June 08, 2012 4:46 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com <mailto:
> CAD_CAM_EDM_DRO%40yahoogroups.com>
> Subject: Re: [CAD_CAM_EDM_DRO] Re: small spindle ?
>
> Jeff,
>
> I don't believe the motor used in those spindles is the same type as a
> battery powered drill. Why would they be? The bearings in any high speed
> spindle, small trim router motor, or a rotary tool such as the Proxxon are
> going to be radial bearings. Radial bearings are specifically called for
> when side loads are high. I suspect the bearings in the spindle in question
> (in the link) will last as long as the quality of the bearings used not the
> type of motor.
>
> However .0015 runout is pretty high for a spindle. It would have to be
> made pretty poorly to have that much runout. I can tune a drill press with
> a hammer and get runout that good (or poor). It's probably good enough for
> a hobby machine since it's too small to measure with most calipers. I
> suspect the poor runout specified is the result of the chuck used, not the
> motor bearings.
>
> Any idea what the runout of a trim router would be? Probably pretty low
> until the chuck is added. I would think that even a collet like the
> PreciseBits would be fairly difficult to mount to a router without
> increasing the runout. Seems to me that the only way to get precision for
> cheap would be a belt driven spindle. That would take the runout of the
> motor out of the equation.
>
> ljg
>
> Larry Guthrie
> yrralguthrie@... <mailto:yrralguthrie%40yahoo.com> <mailto:
> yrralguthrie%40yahoo.com>
> larry.guthrie@... <mailto:larry.guthrie%40yahoo.com> <mailto:
> larry.guthrie%40yahoo.com>
>
> ________________________________
>
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