Myford Gearbox drain seal washer

Did you find a suitable washer?

The referenced seals are known as 'Dowty washers' because they were invented by (who else?) Dowty!

Hello Mark,

I had a similar problem with the QCGB of my Myford S7. The sealing washers on the QCGB drain plug and the cover for the lower mounting screw on my lathe were neoprene. I noticed the part number and description in the Myford manual called out Dowty washers. After finding out what they were and sourcing them from the UK (I am in the USA) I replaced them. However, it still leaked. I put a pan under the gear box and was fairly confident the leak was coming from there because I had to constantly top it off. Kind of hard to isolate an oil leak on the Myford because of the total loss oil system. Also was second guessing myself on wether I installed the o-rings properly between the QCGB and the bed on assembly when I originally moved the lathe.

​​This is the pan I used.

When the Dowty washers arrived, I drained the QCGB and by chance looked at the sealing surface of the drain plug with a mirror and flashlight. Found a low spot that appeared to be galling from the spot facing when it was machined.

I removed the QCGB, cleaned it with mineral spirits to remove all traces of oil, especially in the threads for the drain plug. Packed the threads with cotton balls and carefully draw filed the spotface flat. Carefully removed the packing in the threads and cleaned everything again.

Reassembled everything again with new Dowty washers. After several months of monitoring, am pleased to report that the QCGB is no longer leaking.

Hope this may help someone else who is frustrated by their Myford QCGB leaking.

Kind regards,

Mike

Mike, is that a 5C collet chuck on the Myford? If so could I enquire where you purchased it from as I have a box of collets and no chuck and have been told that a collet chuck is too heavy for a myford

Hi Baz,

Yes, that is a Bison 4” Diameter 5C collet chuck. Bison even sells a 1-1/8”-12 BSW backplate for it.

**LINK**

I purchased mine from New England Brass & Tool. (USA)

This is a standard Bison item.

4” Bison 5C Collet Chuck (Plain Back) #7-862-0401 $495

Fully Machined Threaded Adapter 4” No.7-922-046 $95

Very happy with mine. The 4” diameter is the perfect size for the Myford lathe. Not available in a Set-Tru type.