A sharpie on the comm makes it very easy to see the progress. Right before the last lathe pass, we clean the gap, and then use the ballpoint pen, then the last pass, this keeps a sharp edge on the comm to keep the brushes clean. In 10th scale 4 minute races we did not notice a difference , but 12th scale 8 minutes racing it did make a diff.
The setup is Parma #502. That arm is Pro Slot (Speed FX). Those Chinese Pro Slot arms have very soft copper coms but are thicker and bigger diameter than the barely harder ,thinner and smaller diameter Parma arms. I recommend the Gold dust brushes on the Chinese Pro Slot as they are softer and easier on the com. With a light spring such as a Champion red(med) or green (light).
This is something i never saw much use for, All my arms were always pretty straight and never needed truing. I tended to use heavier springs for better brakes so maybe that helped. I tended to build low timed S16 magnet torque monsters that loved tall gearing, Our trak at the time, 1990's, had some fairly loose rules as far as a stock class motor. When we'd run like regionals (Bigger races), we'd run their rules of course and build for them, but we had our own setups we liked to run locally. The funny thing, almost everyone had their own thing (Secret sauce if you will) and all were about equal
good video glad i found it.brought back memories for me ..i was a slot car mechanic 25 years ago ...i use to use a big lathe to clean up armatures on 16d and group 20 motors ..here in australia .
Cheers James. Perfect timing for me because I've just bought a barely used Hudy comm lathe from ebay for £36! I've been practicing on some old arms and plan to practice rebuilding some old Scaley Johnson 111s as practice pieces before I go anywhere near my G12 or strap car stuff. Really enjoying these videos especially. Thanks again.
Great. Just bear in mind that if the Hudy comm lathe was intended for RC motors you may have to machine the tool holder and v blocks to get the tool to sit in the centre line of the shaft.
It's unusual to see that much smearing of the metal into the comm slots - maybe it's a very soft copper. Or possibly the cutting tool is past its best - even diamond bits do wear. I've found the best finish, using both carbide and diamond cutting bits, comes from using a high speed and a deeper cut - i.e. go straight to the finished size, rather than creeping up on it in very fine passes. I also like to 'paint' the comm with a sharpie first - makes it really easy to see where you've cut, and adds lubrication.
Thank you Wink for those tips. I was surprised at how much copper was burred into the slots. The tool cuts fine on other coms, so it must be the very soft copper on this armature.
@@CleaveTech The worst comm cutting experience I ever had was when I decided to retrue the commutator in the washing machine motor. Probably 20 or so segments (I used a bigger lathe than the Hudy lol). They all smeared into one big soft mess😨. I spent the next half day making a tool to recut the slots.
It makes a small difference depending on the length of race and the gearing you are permitted to use. With G12 armatures in Production 24 I use 46 to 48 degree armatures.
Hello there ! - this happens because Com is cheap / poor quality + Plus = It looks someone used higher spring pressure and a very abrasive brushes such as proslot goldust wich causes higher amp + higher temperture
@@ACCOUNTANTB , it runs really nicely now it has a ball race in the can and is installed in the car. Can’t wait to try it out in a few weeks time with its owner.
A sharpie on the comm makes it very easy to see the progress.
Right before the last lathe pass, we clean the gap, and then use the ballpoint pen, then the last pass, this keeps a sharp edge on the comm to keep the brushes clean. In 10th scale 4 minute races we did not notice a difference , but 12th scale 8 minutes racing it did make a diff.
The setup is Parma #502. That arm is Pro Slot (Speed FX). Those Chinese Pro Slot arms have very soft copper coms but are thicker and bigger diameter than the barely harder ,thinner and smaller diameter Parma arms. I recommend the Gold dust brushes on the Chinese Pro Slot as they are softer and easier on the com. With a light spring such as a Champion red(med) or green (light).
This is something i never saw much use for, All my arms were always pretty straight and never needed truing. I tended to use heavier springs for better brakes so maybe that helped. I tended to build low timed S16 magnet torque monsters that loved tall gearing, Our trak at the time, 1990's, had some fairly loose rules as far as a stock class motor. When we'd run like regionals (Bigger races), we'd run their rules of course and build for them, but we had our own setups we liked to run locally. The funny thing, almost everyone had their own thing (Secret sauce if you will) and all were about equal
Great information
good video glad i found it.brought back memories for me ..i was a slot car mechanic 25 years ago ...i use to use a big lathe to clean up armatures on 16d and group 20 motors ..here in australia .
Did you do this as a service for all racers in Australia?
I love rebuilding motors so any new tips are always welcomed.
Thank you. I plan to do more videos on motor building in the future.
A wooden toothpick works great for cleaning out the commutator slots :-)
Yes Ron. A tooth pick is probably better than a knife a preventing any damage to the slots. I am very careful with my knife though 😉
Cheers James. Perfect timing for me because I've just bought a barely used Hudy comm lathe from ebay for £36!
I've been practicing on some old arms and plan to practice rebuilding some old Scaley Johnson 111s as practice pieces before I go anywhere near my G12 or strap car stuff.
Really enjoying these videos especially. Thanks again.
Great. Just bear in mind that if the Hudy comm lathe was intended for RC motors you may have to machine the tool holder and v blocks to get the tool to sit in the centre line of the shaft.
Yes I've already worked that out. I used to be a toolmaker years ago so I'm familiar with the issues.
Good video, and perfect timing for me, since I have a few arms that need to be trued, and just bought a used comm lathe to do it.
Thanks for watching and I hope the com truing went well.
It's unusual to see that much smearing of the metal into the comm slots - maybe it's a very soft copper. Or possibly the cutting tool is past its best - even diamond bits do wear. I've found the best finish, using both carbide and diamond cutting bits, comes from using a high speed and a deeper cut - i.e. go straight to the finished size, rather than creeping up on it in very fine passes. I also like to 'paint' the comm with a sharpie first - makes it really easy to see where you've cut, and adds lubrication.
Thank you Wink for those tips. I was surprised at how much copper was burred into the slots. The tool cuts fine on other coms, so it must be the very soft copper on this armature.
@@CleaveTech The worst comm cutting experience I ever had was when I decided to retrue the commutator in the washing machine motor. Probably 20 or so segments (I used a bigger lathe than the Hudy lol). They all smeared into one big soft mess😨. I spent the next half day making a tool to recut the slots.
How does your friend balance the motor? Does he have a gadget that spins it up and determines the heavy side?
Can you just unwind the windings, remove the electromagnet cores and replace the shaft?
Hello Cleve, what rotor degree would you recommend for Production 24?
It makes a small difference depending on the length of race and the gearing you are permitted to use. With G12 armatures in Production 24 I use 46 to 48 degree armatures.
Hello there ! - this happens because Com is cheap / poor quality + Plus = It looks someone used higher spring pressure and a very abrasive brushes such as proslot goldust wich causes higher amp + higher temperture
Hi Chris. Yes, I think the com quality is not very good. This doesn’t happen with the coms on open armatures from PK or Valiko.
MAN....for shure man !! - ahahahah - Its so fun to push those old arms to limit....specially parmas - gotta have balls = risky business
@@ACCOUNTANTB , it runs really nicely now it has a ball race in the can and is installed in the car. Can’t wait to try it out in a few weeks time with its owner.
Using a needle would be way better since it's tip is really tin.