Re: [CAD_CAM_EDM_DRO] NEMA 34 motor mounting question

For starters, the NEMA Series motors use 'Imperial/Metric'
specifications. The 5.5 mm (.218" ) holes are for 5mm
screws, and the 72.95mm (2.872")x 1.5mm (0.06") pilot-boss
is for precisely locating the shaft concentric to a 73mm
(2.875")c'bore in the device being powered. Even the
bolt-circle mounting has Imperial or Metric dimensions.
It's a conspiracy... just ask 'Minnesota' Jon Kutz.

RayHex

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> From: Hans Wedemeyer <xyz@...>
>
> I about to mount a NEMA 34 motor, it has a square front

plate with four equally space mounting holes.

> The hole diameter is 0.218 which seems sloppy for 10-32

and too tight for 12-32.

> I feel like I should be using 12-32.
> Is it normal to expect the end user to drill these

mounting hole to suit !

>
> Next question:
> The front mounting plate is not complete flat, it has a

raised portion (0.06") and round (2.872 diameter) .

> When I mount this to a plate I will have to remove that

same amount of metal ( and a little extra) to ensure the
motor is bolted flat to the mounting plate.

>
> What is the purpose of round raised portion !
> To me it would be better if front was flat ?
> I expect there is a good reason for this strange

arrangement.... May be to make more work for machine shops
!