MTFCA Forum

Does anyone know if/where I can rent a KRW mag gap tool…
Many thanks and Cheers!

Ed

Apparently Snyder's used to offer a reproduction, but I don't see it in their current catalog.

https://www.mtfca.com/discus/messages/1 ... 1269355108

MAC's webpage still shows the repro gauge available, if you want to take a chance dealing with them.

https://www.macsautoparts.com/model-t-f ... 699-1.html

CudaMan wrote: ↑

Wed Nov 15, 2023 11:51 am

MAC's webpage still shows the repro gauge available, if you want to take a chance dealing with them.

https://www.macsautoparts.com/model-t-f ... 699-1.html

Out of stock.

Edwin, have you checked with any model t club by you ?

Anyone have an instruction sheet for the gap gauge they could post here?

I'll look Dan but I think there is instructions in the later Ford Service Bulletins.

Found this from Ron Patterson.
 

Thank you both!!

I’m pretty sure the late Bob Scherzer made the reproduction KRW magneto gap gauges. I don’t know if anyone else has carried on with production of them.

Dan: I think I've got it - at least what Steve is referring to. This is from the Service Bulletins, also in the Service Bulletins Essentials book. In just the second paragraph it states, "make sure that the flange of the transmission shaft is free from dirt and burrs..." What they don't mention is for you to drop a transmission shaft onto the flywheel first before installing the gap gauge so you can get proper clearance. It's been awhile since I've done this procedure but hopefully this helps. Bob's calibration from Ron Patterson is important as well. Clicking on the photos seems to clear them up some.

Service Bulletin Essentials Book

Sean those are great contributions thanks, from the standpoint of ease of use, we cut an old shaft down after squaring the flange, that way you can follow the procedure initially on the flywheel while on your shop table.

Best Regards John

Just sent John…Thank you!

Up till most recently I have used a homemade unit From spare, used parts. A D/S bearing sleeve, heavy rod with wrist pin & a long all thread bolt thru the wrist pin. I think I got the info on this DIY unit from "tinkering tips".

Anyway, I got the urge to acquire a KRW unit. Flywheels are getting to heavy to R&R the dozen times it takes to get the proper field coil clearance.
So I got loaned the KRW gauge Thinking it would be a one step to get the field coil spaced up with ONE flywheel install.

I got all the info: the service bulletin procedure & Ron's calibration info.
The caveat that the tool only works if the 3rd main is cut according to the KRW method. Mine was not

Good news/ bad news. Result was the calibrated tool got me .030 to far away, but the field coil was properly spaced all the way around.
Adding the extra .030" in shims got me there. Only 2 or 3 flywheel R&R's. Beats 12 or so.

My conclusion: The KRW tool was not more useful Than my home made gauge tool to justify the $2-300 the KRW tool is likely to cost me.

I have successfully used my home made tool on flywheel magnets for many years.
I have not tried to set a field coil with it. I will with an upcoming motor.

John T: Good tip on cutting a flange from the shaft. I happen to have a cutout in my bench for the trans/flywheel similar to the KRW Transmission Bench seen below. You make an important point - squaring up that flange. I will add to that that you should check the flange on the gap gauge as well. Mine was not true when purchased.

Speedy John: I've never had much luck setting the field coil with the gap gauge. I'm curious to know if others have? As for the price, I was lucky to get mine (repop) many moons ago, slogging through the miles of mud at Hershey. Of course, there was the price of the plane ticket to get there and back as well .

Funny you should mention re-squaring the base flange.
I had to do the same with the unit I had borrowed. Trust but verify.
Tool post grinder, ya.

I had a machinist buddy make this shaft fixture for my Stevens rod alignment rig - works great for setting the magnet height.

RajoRacer wrote: ↑

Fri Nov 17, 2023 1:01 pm

I had a machinist buddy make this shaft fixture for my Stevens rod alignment rig - works great for setting the magnet height.

Sweet!

I would also be interested in The successful/easy setting up a field coil spacing.

I’m guessing I’ve set the magnet heights on around 100 flywheels, and for most all of those I’ve used the KRW tool. It generally takes 2-4 tries to get well within spec. There probably wasn’t one time that I was happy with the clearance on the very first try.

The KRW tool is essential because it allows you to do in two or three repetitions, the work that could take 5-10 tries without it.

Adam wrote: ↑

Fri Nov 17, 2023 1:59 pm

I’m guessing I’ve set the magnet heights on around 100 flywheels, and for most all of those I’ve used the KRW tool. It generally takes 2-4 tries to get well within spec. There probably wasn’t one time that I was happy with the clearance on the very first try.

The KRW tool is essential because it allows you to do in two or three repetitions, the work that could take 5-10 tries without it.

Adam, I am unclear what you mean by "2-4 tries"
As I understand & do, you attach the tool rotate it, Find the high magnet keepers & set them lower by your chosen means. (brass hammer, C-clamp or press.) Repeat until all magnets are close to the same height.

This is all setting magnet height on a fly wheel.

But, how do you set the field coil @ the block to be in spec for field coil & flywheel?

So--------- the fly in the ointment here is that the distance from the crank flange to the mag ring mounting surface on the back of the block is not necessarily the same on every engine, and that exact dimension needs to be considered when using a gauge to set the gap. Anyone have any info on what the "official" dimension is?? Factory drawings of the rear cap, crankshaft and block would provide the info needed to come up with this...........

its never easy!!


but is sure is fun!!

Amen.
There is a dimension out there , In the service manual I think.
I wanna say a straight edge on the crank flange to the field coil measured with a scale.
27/32'' or 0.8437. Revised dimension

I suppose one could use a depth micrometer with a bar.
Or use the dimension to adjust the KRW tool to it.

It would get you in the ballpark. But you would have to adjust for the actual magnet height which varies flywheel to flywheel.
Thats where the beauty of the KRW tool comes into play (in theory)
Flip the indicator arm & set the field coil to it. But the 3rd main positioning of the crank flange variability messes this up.
Fortunately it will get you close.

What do the very experienced motor builders do??

So why not try mounting and leaving the field coil loose and then mount the fly wheel. With the magnets holding the field coil up tight against the flywheel you can measure the gap between the block and field coil. Install the shims with the gap you want and you should be very close.

SurfCityGene wrote: ↑

Fri Nov 17, 2023 4:32 pm

So why not try mounting and leaving the field coil loose and then mount the fly wheel. With the magnets holding the field coil up tight against the flywheel you can measure the gap between the block and field coil. Install the shims with the gap you want and you should be very close.

Thats an interesting idea. Thanks Gene.

Yeah, what he said .
Have done this successfully after seeing this article by Mike Vaughn in The Vintage Ford. I hope it's okay to have posted it here and Thanks Mike!

I do a similar procedure with my KRW tool - set the magnets on the flywheel, install the field coil & check the distance with the KRW tool, record the gaps then remove the tool & drop the flywheel onto the crank, bolt it down then with brass feeler gauges verify the gaps again and shim accordingly.

I have a job coming up next week to do one. I'll measure the crank to field coil distance and make some notes and report back.