Myford Speed 10 Headstock Bearings Question

[“Bill Hancox”Participant @billhancox]

Can anyone tell me the difference(s) between a 30205 bearing, a 30205A bearing and a 30205J bearing? I have not been able to get an adequate answer for this either from local suppliers or on line. I have removed 30205J and 30206J bearings from my lathe yet the manual specifies 30205A and 30206A bearings. Hmmmm. Methinks I need a 1/2+1/2.

[“Bill Hancox”Participant @billhancox]

What’s the difference?

[“Bill Hancox”Participant @billhancox]

This is an example of the info that I found online:

A: SPECIAL INTERNAL DESIGN OR MANUFACTURING CODE.

J: RADIAL INTERNAL CLEARANCE AND MANUFACTURING PRECISION. THE FIRST DIGIT DENOTES THE ISO RADIAL INTERNAL CLEARANCE CATEGORY.THE SECOND DIGIT DENOTES THE ISO PRECISION CLASS, E.G. : J36: RADIAL INTERNAL CLEARANCE CATEGORY 3, ISO PRECISION CLASS 6 (ABEC 3). EQUIVALENTS: J20 = C2, J30 = C3, J40 = C4 AND J50 = C5.

I will try a query to SNR

[blowlampParticipant @blowlamp]

See here **LINK**

I'd just fit some good quality off the shelf bearings for this application.

Martin.

[Michael GilliganParticipant @michaelgilligan61133]

Explanatory text on page 2 of this

… Mercifully brief.

MichaelG.

[“Bill Hancox”Participant @billhancox]

A good quality generic bearing seems to be the predominate advice. myford.co.uk sells the bearings. I noted that the part numbers depicted in their photos have the suffix "A" so I will probably order those.

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