The Steamboating Forum

Gentlemen,
The photo shows two con-rod, bottom-end, shell bearings which run on a 3/4" pin.
One has Teflon (?) faces with the back stamped '12D x 16' or '12DX 16'. Below this is a 'G' within a square box and the letter 'N'.
The other bearing is a plain bronze split shell with no identifier.

I have Googled 12D x 16 and its variants every which way but still come up with zilch every time. Can anyone suggest where I can find replacements??

Of course, nobody would have taken a split bush, split it again and fitted it as two bearing halves, would they?...........................

Regards,
Old Steamer

Hi,
The one on the left is a DX type made by Glacier metal, and nowdays by many others. These are usually supplied as a split bush. I have made these into a pair of halves with success by carefully milling the cut end in a fixture, of course you need two bushes to make two halves.
Regards
Jack

Jack,
That was very quick! You have confirmed what I suggested in my last sentence - but I didn't think it was right!
In your experience, is there any advantage in using the Teflon variety over the plain bush?

Thank you,
OS

The Glacier bearings are considered to be "oil free", self lubrication under some conditions. They can be run with lubrication as well. The benefit would be potentially better longevity in a system where lubrication is intermittent or poor at times (I don't know anywhere that would apply )



Ken

The DX range are not oil free they depend on marginal lubrication, the DU range are oil free but a bit of oil does no harm. For a crankpin bearing then oil is essential.
I always use a lube system which is positive, for DX bearings such as that fitted to truck chassis/machine tools etc.
I prefer the single line system using Interlube flow units.
Jack

steamboatjack wrote:The DX range are not oil free they depend on marginal lubrication, the DU range are oil free but a bit of oil does no harm. For a crankpin bearing then oil is essential.
I always use a lube system which is positive, for DX bearings such as that fitted to truck chassis/machine tools etc.
I prefer the single line system using Interlube flow units.
Jack

Jack, Your correct

At first glance the bearing looks like a solid lubricant insert bushing. Now that you mention the DX, I can see that it's likely that bearing is indeed a metal-polymer composite bushing.

Jack,
It looks like I am going to follow your lead and make half bearings from a single split bush. Will you advise more details of your procedure?
Thanks,
OS

The way I did it some time back was as follows.
Each bush is cut to make an oversize half, these are then held in a bearing housing with a strap across and the edges carefully milled to form an exact half shell.
As there was no way to stop rotation of the shell, I secured them with high strength loctite 638. After fifteen years they are still good. I used the metric DX bearings which come finished size.
Obviously the housing has to be made to the glacier tolerance. and the journal should be also ground to the correct tolerance & finish.
Since then I have had success using “oilite” bushes, in this case I cut the bush in two and machine to leave a “gap” of 4mm each side. The bearing is assembled with a spacer made of 4mm “carp brand” tufnol. This spacer abutts the journal at the axial ends to retain oil. Rotation is prevented by a brass hollow pin which supplies the oil, or can be achieved using the bearing studs being let into the outer diameter of the bush.

Regards
Jack

jack,
Thanks for that. I'm obliged
OS