A few PA speedometer questions

[RupertW]

Evening all, 

I'm refurbishing a PA speedometer for the chummy project and have a few questions I'm hoping for some answers on:
- should any specific type of grease be used on the ball bearings, or will general purpose grease do?
- again with the general mechanism I'm assuming a light oiling makes sense?
- I think I've read the ball bearing size is 1/16 inch, can anyone confirm this?
- the speedometer actuator arm has an extension with a hole that looks like a spring should go through it - I've not managed to find any reference pictures that show anything along those lines, but I don't understand why it'd be there if not necessary? I'll try and post a picture to explain what I'm asking unless somebody knowledgeable understands what I'm trying to ask!

Any help much appreciated as always

[David Cochrane]

- I was advised to use Rocol Sapphire grease (not the ordinary stuff).
- Light oil (not WD40!).
- Ball bearings are 1/16", available from A7 Compinents (BG44b).

[Jeff Taylor]

Re your 'speedo actuator arm / extension with hole / spring' - it may be worth joining the 'Smiths Magnetic and Governor Speedometers' Facebook Private Group and seeking advice there. The group is run by Michael Flannery an expert at restoring Smiths speedos and very knowledgable - he'll know the answer.

https://www.facebook.com/groups/2151645781645054

[Howard Wright]

Hi Rupert

I’ve rebuilt two PA speedos and neither had a spring attached to the top of the needle actuator arm. Both seem too work OK without.

Do make sure you work over a tray so those ball bearings or face plate screws don’t go walkabout. Also be careful not to bend the governor ball when tightening up the bearing races otherwise the needle flickers wildly (don’t ask me how I know this  ).

Cheers

Howard

[RupertW]

Thanks all for the advice - I've been rebuilding it over a tub which has done a good job of catching various bits of it. Most of the ball bearings were already missing or loose when I disassembled it so I'll be in touch with David about some new ones

[Vancevr]

I am doing the same project. The 1/16 ball bearings didnt work they were too small. The worm gear that turns the odometer didnt reach. So i bought some 3/32 bearings and they worked on the top but not the bottom they would jump around whenever I spun the mechanism. So I used the small on bottom and bigger on top. Now when I spin it I can let go and it will coats like it should. But now that same gear and shaft keep lifting away from the worm gear. I also am using marine grease it seems to work good.what should I do next

[Jeff Taylor]

I would suggest joining the Facebook group I posted a link to in my above post - 'Smiths Magnetic and Governor Speedometers' run by Michael Flannery and seek additional advice there.

https://www.facebook.com/groups/2151645781645054