Generator/Starter Brushplate Brush Holder Thread Repair

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Model T Ford Forum: Forum 2011: Generator/Starter Brushplate Brush Holder Thread Repair
Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Wednesday, November 30, 2011 - 12:04 pm:

Stripped 10-32 screw holes on soft metal brush holder castings on generator and starter brushplates is a common problem.
I went searching for a thread repair solution trying several methods. I was not impressed with Helical Inserts; too many expensive tools required to properly install.
This method I found is the cheapest and works best; it is a 10-32 Keylock Thin Wall Threaded Insert.
1
In the attached photo you can see the two inserts before installation, the key setting tool and both sides of a repaired brush holder. The stripped hole is drilled out with a letter "I" drill (as you can see there is sufficient surrounding material to support the insert), thread the hole with a 5/16-18 tap, thread the insert into the hole so it is just below the surface, set the two tangs with the tool shown and you have a bullet proof repair.
I tried to upset the installed insert with a large screwdriver and, save breaking the casting, could not.
You can buy a kit with a enough inserts to repair one brushplate and a key setting tool. Let me know if you want the source?
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem on Wednesday, November 30, 2011 - 02:57 pm:

Ron,

I think it's worth noting that the exact position that you chose to locate the locking keys is probably essential to a good outcome. You have them carefully located in the "meat" of the part. Any other arrangement looks as if it might split the ear off.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Levans - Lafayette, Indiana on Wednesday, November 30, 2011 - 03:52 pm:

Ron,

Can you post your source? That looks like it might be a good thing for many small applications.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Wednesday, November 30, 2011 - 06:21 pm:

Paul
McMaster & Carr has a kit (#91731A009) with 9 inserts and setting tool for $34.69 and R.J.& L. 315-986-7121 has a kit (#12374) with 4 inserts and tool for $12.30.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Wednesday, November 30, 2011 - 06:32 pm:

Jerry
The photo is not very good. There is more metal surrounding the tapped hole than it appears.
Also letter "I" drill is a bit larger than the usual tap drill for a 5/16-18 tap. Apparently this allows the keys to set only into the tops of the threads in both parts thereby helping to prevent excessive pressure and possible breakout in soft metal parts.
I have made this repair in many brush holders and this is really a great solution to this particular problem.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Wednesday, November 30, 2011 - 10:30 pm:

Looks to me like a 10-32 helicoil should work just fine with a lot smaller hole than an I-drill. In Dallas, we can usually get helicoils and tools at CDC surplus. Local hardware stores carry them also.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem on Thursday, December 01, 2011 - 11:03 am:

Yes Ted, but Heli-Coils, especially small ones, can be very finicky to install. Even more so if you don't have their special insertion tool.


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