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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