permaglide bushes

[geoff walker 1Participant @geoffwalker1]

Hi All,

Has anyone any experience of using these. I thought about using them as main bearing inserts to carry the crankshaft on my new engine. Crankshaft would be 8mm dia mild steel or possibly silver steel. Engine will need to run at low and high speed Geoff

Edited By JasonB on 31/10/2018 13:26:02

[geoff walker 1Participant @geoffwalker1]

[Jeff DaymanParticipant @jeffdayman43397]

Two things to check before using these in an engine – 1. max temperature of operation 2. PV factor with the kinds of pressure caused by piston forces , and the velocity range, in an IC engine or high speed steam engine (you don't mention what type of engine you will be making).

I think you will find that all metal bearings of some sort will be needed, rather than PTFE lined shells.

[egaParticipant @ega]

Some may remember Derek Beck's First Affaire with a Lathe series in ME in which he described building a milling spindle using (from memory) "Glacier DU" bearings. As I recall, when he was running in the bearings tiny fragments of PTFE were released.

[Neil WyattModerator @neilwyatt]

See the 'technical tab':

d = 8mm

D =10mm

b =10mm

Structure =Steel support strip S.A.E 1010. Sintered bronze layer. PTFE and lead combination

Maximum static load = 250 N/mm²

Maximum dynamic load = 140 N/mm²

Maximum sliding speed = 2.5m/s dry 5.0m/s with oil

Operating temperature = -200° C to +280° C

Thermal conductivity = 46 W/mk

Coefficient of friction (dry) = 0.02 to 0.20

Coefficient of friction (oil lubricated) = 0.02 to 0.15

Recommended housing tolerance = 4.5mm/5.5mm H6
7.0mm/305mm H7

Recommended shaft tolerance = 3.0mm/4.0mm h6
5.0mm/75mm f7
80mm/300mm h8

Recommended shaft finish = Ra ≤ 0.4um (N5)

Recommended shaft hardness = HB > 200

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