Spinneyhill Posted September 25, 2015 Share Posted September 25, 2015 I want to remove and replace the munted pole shoe screws on the generator on my 1930 DC. At the same time I'll rewrap the field coils. I want to make sure I can get new screws before I attempt to remove the old ones. What size and thread are the pole shoe screws? They appear to be 5/16" with a fine thread but I can't get a 5/16" UNF bolt to screw into the inside where there is a bit of thread. The generator was made by The McKinnon Industries in Ontario, no doubt under license. I assume the screws would be a universal Delco Remy size and the same as in the model 943S or M or J or ? generator made by Anderson Ind. in the USA. Link to comment Share on other sites More sharing options...
ArticiferTom Posted September 25, 2015 Share Posted September 25, 2015 Hello , All electric screws are usually number sizes in US products anyway . They will be 10-32 size 10 and tpi is 32 , other common electric sizes are 8-32 ,6-32 , 10-24 a coarse thread . If you think of 14 size is 1/4" next size down is #12 , then #10 which might look around 5/16 " . Try to replace with same ie if brass . Screws can be got at used appliance, home reno store . Some receptacles use 10-32 to hold wire on side or ask your local electrician . Link to comment Share on other sites More sharing options...
Spinneyhill Posted September 25, 2015 Author Share Posted September 25, 2015 Thanks for that Tom. But Oh Boy, another set of number sizes! Impenetrable to the unitiated like me. The connectors are #8 and #10 but less than 0.2"! The metric system has a lot going for it with the only numbers being the actual size; no conversion tables to carry around in your head. Link to comment Share on other sites More sharing options...
ArticiferTom Posted September 25, 2015 Share Posted September 25, 2015 Yeah. Don't know what came first but the numeral system is what's used on most guns .So it is pretty old . And can go very small and fine ie 4-40 which makes great replacement for rivet in brass , 3-56 and 2-? for attaching a nats ass to pen top . Link to comment Share on other sites More sharing options...
Spinneyhill Posted September 26, 2015 Author Share Posted September 26, 2015 It is a right pickle. There is AWG, SWG and screw numbers, then another set of screw numbers, then there are drill numbers, metal gauge, taper numbers and so on. Everyone had to have their own system so only their trade knew what they were talking about. Another I heard a couple of days ago was wire gauges like 150, 120 and so on. No idea what they are, something British presumably coz the man was an Austin parts supplier. Presumably auto-electricians know those numbers. Link to comment Share on other sites More sharing options...
Spinneyhill Posted September 26, 2015 Author Share Posted September 26, 2015 (edited) I am now confused. The pole shoe screws are the two large-headed countersunk slotted screws that hole the field coils in. They are messed up by using too small a screwdriver and using insufficient force to keep the screwdriver in the slot. I have found one chart that goes up to 24 gauge = 0.372". Other charts, including the ANSI chart which is not complete, go to number 10 = 0.190" then hop to 1/4" (12 ga. = 0.224"). 5/16" are either 18 or 24 tpi in the ANSI chart. The pole shoe screws have oversize heads. They seem to be hard to source. Edited September 26, 2015 by Spinneyhill (see edit history) Link to comment Share on other sites More sharing options...
ArticiferTom Posted September 26, 2015 Share Posted September 26, 2015 (edited) My mistake did not know you are removing the screws on out side holding pole coils . That takes an impact screwdriver with large tip . It will be a SAE thread 1/4x20or 28 , 5/16x18 or24 flat head screw . Boy ! let me think where you'll find them . The number sizes we where talking about deal with wire /electrical parts , that's why I said about brass / bronze for conductivity . Should find any junk North American starter or generator may have , starters may be more common . Next best that bolts of size turn half the head to taper and wrench in or all head and slot it . I do not even pull my coils out to clean . That I would only do if they were bad , just clean around it with electra-clean spray , let dry good . Be sure to test for ground on all wiring before assembly . Remember if is Three brush unit to test before you ground field wire . If you cannot get, I'll gladly find and send you replacements . I'll just have to figure out how . Edited September 26, 2015 by ArticiferTom (see edit history) Link to comment Share on other sites More sharing options...
dmgoulet Posted September 26, 2015 Share Posted September 26, 2015 (edited) I found some new ones on ebay (for generator and starter) Edited September 26, 2015 by dmgoulet (see edit history) Link to comment Share on other sites More sharing options...
Spinneyhill Posted September 30, 2015 Author Share Posted September 30, 2015 Well I got the screws out. I made a press out of my cheapo bearing puller and a screw driver out of a grade 10.9 5/8" bolt. The bolt also had a hole in the top for the pointy tip on the puller rod. Put all together and tightened, gave the top of the puller a few taps with the aluminium hammer, than tapped the spanner and it moved. No damage to the screws. Photos of the arrangement are attached. Link to comment Share on other sites More sharing options...
ArticiferTom Posted September 30, 2015 Share Posted September 30, 2015 Wow . That is great tool . It is a shame it takes so much work to do so little on some projects . I checked out the screws on ebay talked about above NOS , but assume yours are fine now . They said they where sae 3/8- 16 . And recommended using a bolt first to pull and, form in coils , then change back to screw . I think a little Locktite might be in order also . Tom Link to comment Share on other sites More sharing options...
Spinneyhill Posted September 30, 2015 Author Share Posted September 30, 2015 These are 3/8"-24. I will use the same set-up to replace them. It looked like they had a little grease or something on them, perhaps copper-cote. The screw heads are in rough condition. I cleaned up the slot a little with a Dremel thin grinder wheel. I'll put in new screws so they look nice. I have seen a photo somewhere of a device to hold the pole shoes in place while the screws are inserted. Link to comment Share on other sites More sharing options...
ArticiferTom Posted September 30, 2015 Share Posted September 30, 2015 Great glad to hear . Is your generator a three brush .If so, you know you can test and flash it by running like a motor while disconnected from fan belt . I'll send you more info if needed. This ONLY works on one wire units . Spend my day rebuilding my clum 9150 light switch . Been having all kind of electrical issues since I got rid of second fuse they had parrelled on amp gage .The system was way over loaded with the sealed beam lites and high resistance grounds . Found one in steering column horn wire and clum, dirty, switch and know brake light switch, in master cylinder . Tom Link to comment Share on other sites More sharing options...
Spinneyhill Posted October 2, 2015 Author Share Posted October 2, 2015 Yes, it is three brush. I'll be looking for that information about testing etc. in a few days. I have some orchard chores to do first: the passionfruit wires need to be in pronto or the plant will run wild all over the place. Remember the generator was running fine, it just squeaked at the brushes when it was turned by hand. Link to comment Share on other sites More sharing options...
MikeC5 Posted January 24, 2016 Share Posted January 24, 2016 (edited) When you say re-wrap the field coils, do you mean re-wind them with new wire? I have an SG with a field coil problem but haven't had any luck finding someone willing to re-wind them. I have a spare that I can practice on but getting those pole screws out will take an effort similar to yours. How hard would it be to rewind them, assuming you can buy the correct gage/insulated wire? Edited January 24, 2016 by MikeC5 (see edit history) Link to comment Share on other sites More sharing options...
ArticiferTom Posted January 24, 2016 Share Posted January 24, 2016 No, Mike C he was talking the tape on outside and re-varnish it . To me not really needed if connections are ok or accessible to repair where solid wire meats stranded . If you have a bad coil ,it would be much cheaper and easier to buy replacements . Link to comment Share on other sites More sharing options...
Spinneyhill Posted January 24, 2016 Author Share Posted January 24, 2016 As Tom said. The tape was in reasonably good condition after a clean. The main problems were squeaky brushes and rumbly front bearing. Now back in service, looking lovely with new paint. I took the pole shoe screws from a spare: there were unmolested, in perfect condition. After cleanup and zinc plating they were installed. Link to comment Share on other sites More sharing options...
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