Angle of the king pin to the spindle

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Model T Ford Forum: Forum 2009: Angle of the king pin to the spindle
Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Monday, November 09, 2009 - 10:15 pm:

In working on my front brakes I am wondering what was Ford's spec for the king pin "tilt" to the spindle. I don't mean the inclination in the axle itself, just in the spindle. In measuring some it seems to be in the 1-2 degree range off of 90. I wonder what tolerance Ford made them to. I am trying to get the backing plate as square as I can to the spindle and of course I am trying to support it off of the king pin as the McNerny brakes were.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky on Monday, November 09, 2009 - 10:57 pm:

There's two different angles depending on pre-26 and the improved spindle (26-27). I can't find my specs but 1 1/2 degrees on the improved spindle seems to come to mind. I think the pre-26 spindles were 2 1/2 degrees. Someone with a better memory will surely correct me though.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Monday, November 09, 2009 - 11:06 pm:

Ken
The 1 1/2 degree seems reasonable for the 26-7 which is what I have been working on. I wonder how consistent they are?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky on Monday, November 09, 2009 - 11:21 pm:

They should be pretty close. I've seen variation in the machining that would indicate particular care in defining the angle over centering the forging. That's what sets the front wheel camber and Ford knew it was not adjustable.


Top of pagePrevious messageNext messageBottom of page Link to this message  By "Hap" (Harold) Tucker on Monday, November 09, 2009 - 11:24 pm:

Les,

There is a lot of good information on paragraphs 146 to 154 of the "Model T Ford Service" book. A lot of that information is also posted at the thread: http://www.mtfca.com/discus/messages/29/40382.html

I hope some of that may be helpful to you.

Respectfully submitted,

Hap Tucker l915 Model T Ford touring cut off and made into a pickup truck and l907 Model S Runabout. Sumter SC.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Monday, November 09, 2009 - 11:41 pm:

Hap
I had looked at that but it really only mostly applies to the axle, where as I am looking for information pertaining to the spindle itself. My concern is that I may have to build a fixture so that I can ream the king pin bushing to a closer angular tolerance than the average "as found" spindle so that the brake shoes will fit the drum close enough. Well I will check some and see how close I find them.
Thx guys


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky on Monday, November 09, 2009 - 11:43 pm:

Yeah, that thread says 2 vs. 3 degrees but I remember my measurements taken on samples were not even degrees. I would say if you can keep the angle within 1/2 degree (1.5-2.0 & 2.5-3.0) you'd be dang close to the tolerance.


Top of pagePrevious messageNext messageBottom of page Link to this message  By "Hap" (Harold) Tucker on Tuesday, November 10, 2009 - 08:39 am:

Les and Ken,

I'm still not sure if you are addressing the camber (which I see measurements in inches but not degrees) or castor. My limited understanding is the kingpin is vertical without any impact on the castor or the camber. The camber is set by the forging of the front spindle. The castor is set by the forging of the spring perch (and of course putting them in the axle correctly with a proper wishbone etc.). A good axle has all the holes (kingpins and spring perches) parallel in vertically alignment. That is shown in the thread referenced above near the very end - figures 365 & 366.

But either way -- there is a 99% chance you can order a copy of the original Ford drawings for the 1911-25 as well as the 1926-27 front spindle and it should give you the details of that part. If you want to order a copy, contact the Benson Ford Archives [ ].

The 1911-25 right spindle body is part # 2694B and the factory drawing # 280AR.
The 1911-25 left spindle body is part # 2695B and the factory drawing # 281AR.

The 1926-27 right spindle body is part #2694C and the factory drawing # 280B.
The 1926-27 left spindle body is part # 2695C and the factory drawing # 281B.

Respectfully submitted,

Hap Tucker l915 Model T Ford touring cut off and made into a pickup truck and l907 Model S Runabout. Sumter SC.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jeff Humble on Tuesday, November 10, 2009 - 09:25 am:

Les,
I think you will find if you get the spindle drawing that the the hole in the spindle is down the center of the spindle. All bets are off once you press in bushings and ream them. I am looking at a drawing of the front axle and there is no tolerance called out for the angle of the king pin hole, so wouldnt expect one on the spindle either.
pic


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Tuesday, November 10, 2009 - 11:28 am:

I am dealing with the camber which appears to all be in the spindle. There does not appear to be any caster in the spindle.

Jeff
My concern is that I may have to ream the bushings on a fixture to ensure consistent camber so the backing plates fit consistently.
I won't worry about it yet.

Anyway it seems that 1 1/2 degrees seems to be the "factory spec" for the late spindle. My real question is how consistent will they be. It seems likely they will be close enough.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Tuesday, November 10, 2009 - 11:30 am:

Jeff

" I am looking at a drawing of the front axle and there is no tolerance called out for the angle of the king pin hole, so wouldnt expect one on the spindle either." Yet we know there had to be a tolerance, you can not practically make something without.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd on Tuesday, November 10, 2009 - 11:51 am:

IIRC, the angle on '26-'27 is 2 degrees, earlier cars is 3 degrees. Not hard to calculate it out, w/2" camber and 30" diameter wheel on a '26-'27.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robb Wolff on Tuesday, November 10, 2009 - 11:52 am:

Les,
If I understand correctly you are asking what the angle is between the spindle bolt and the spindle. Knowing the angle is important because the backing plate you are designing must be perpendicular to the spindle so that the brakes shoes will seat properly in the drum. That angle establishes the camber of the wheels and Ford literature describes camber as the difference in distance between top and bottom of the front tires. (3” for 30 inch wheels and 1 15/16 inches for balloon tires)

Both the high pressure and the balloon tires are about 30” in diameter (they vary by manufacturer). Using 30” as one side of a right angle triangle and half of the camber in inches as the base this is what I come up with for the angle.

Early spindle 2.86 degrees
Improved spindle 1.85 degrees

I have at least one early spindle that is closer to 2 degrees than three. This is likely because it has been bent due to rough duty. Ken Todd speculates that when balloon tires were first introduced and before the “Improved” spindles came into service a transitionary spindle was supplied that provided the correct camber for the fatter tires.

You and I are coming at the same project from different perspectives. When you and Karin are over for pie I will show you the jig I used to overcome my engineering inadequacies so that I could set up my backing plates correctly.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robb Wolff on Tuesday, November 10, 2009 - 12:02 pm:

The drawing of the early axle shows that the spindle bolt and perch bosses are parallel.axle


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jeff Humble on Tuesday, November 10, 2009 - 12:13 pm:

Les,
Sorry, I may have misunderstood your first post. I agree there should be an angle dimension for the spindle to kingpin bushing hole on the spindle drawing, and the spindle assembly drawing may have a tolerance for the spindle to an after reamed bushing hole. I will be at the Benson Ford Research Center Friday and will see if I can find an answer to that question.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis on Tuesday, November 10, 2009 - 01:03 pm:

If you have the entire drawing, look at the title block. There may be a tolerance there that applies to all angles that do not have a tolerance otherwise noted.


Top of pagePrevious messageNext messageBottom of page Link to this message  By david willis on Tuesday, November 10, 2009 - 04:09 pm:

it would make sense to fixture the backing plate from the axle part of the spindle itself...thus the backing plate is square to the hub no matter where the rest of the stuff winds up with tolerance build up and all....


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Tuesday, November 10, 2009 - 05:18 pm:

Jeff
That would be great and thank you.
David
And there in lies the problem, as there is no good way to attach, short of welding the backing plate directly to the spindle and I don't want to go there.
And so the solution MAY be to jig bore the spindle bushings at the so called optimum angle to the spindle.
Robb
looking forward to the pie!!!!


Top of pagePrevious messageNext messageBottom of page Link to this message  By david willis on Tuesday, November 10, 2009 - 09:23 pm:

les;
while i understand your unwillingness to weld, keep in mind the core of all braking is the axle itself..when i was vintage racing bugattis [well known for their positive 5+++ degree camber in the spindle - the kingpins were parallel.] i would set up the backing plates, mechanical brake shoes,springs, actuating cams etc and chuck up the whole spindle/brake unit on the axle shaft..then i would turn the brakeshoe surface true and to the correct drum diameter with a toolpost grinder. then i would add the spindles to the axle and with everything concentric i would feel safe at 100 mph plus on cable brakes.

oh..to add to the mess, bugatti had no brake shoe adjustment other than shims under the end plates that ran on the actuating cam...another trip to the lathe.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Tuesday, November 10, 2009 - 11:15 pm:

David
The ultimate target is down the road to be able to provide to the hobby a bolt on front brake kit for the T. If I was only making a couple of sets for myself I can easily solve the problems I have mentioned by custom fitting to my own parts. Perhaps it will not be do-able, but I will try.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Todd on Wednesday, November 11, 2009 - 01:10 pm:

Robb, I think the measurement of 30" may be incorrect. True, they are 30" wheels, but, if you look in the service manual, page 47, Fig. 122 you will see that the camber measurement is not taken at the extreme top and bottom of the wheel, but a short distance in.
A sketch of the same picture is also shown on page 377 of the Service Bulletins book.
If you use 28" instead of 30" with 31/32" (1/2 of 1 15/16) camber, the angle comes out at almost exactly 2 degrees.
Maybe Jeff Humble will come up with a true number when he goes to the Benson Ford on Friday.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Wednesday, November 11, 2009 - 03:22 pm:

Ken
That makes reasonable sense compared to the measurements I am getting off of the spindles i have.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky on Wednesday, November 11, 2009 - 08:26 pm:

I think everybody is off. Apparently, there was an error in the historical posts and it just kept propagating. It's not 28" either. More like 20". The measurement is to be taken specifically at the felloe--Not the wheel and not the tire. Using the felloe and 31/32", it comes out to 2.78 degrees.

I can't wait to hear what's on the drawing.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Jeffrey Cole on Wednesday, November 11, 2009 - 09:21 pm:

Could you not machine new spindals with a backing plate attachment area on them?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Wednesday, November 11, 2009 - 09:55 pm:

Mack
I don't know of anyone who wants to pay for new forging dies. And a cast ductile spindle is not in my cards.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jeff Humble on Friday, November 13, 2009 - 11:01 pm:

Les,
I spent the better part of the day today at the Benson Ford Research Center and was unable to find the drawings for the spindle. I found drawings with the spindle drawing numbers but they were not spindles. Could not find any year spindle drawings. I checked the cross reference binder with parts listed by drawing number (factory number), by part number, and by part name, all three sources pointed to the same drawing numbers but the drawings on file were not front axle spindles. I didnt even recognize the parts as being model T.

My wife, brother and sister were with my kids at the Henry Ford for a special Lego exhibt and I had the day to myself in the Benson center! Still didnt have time to get all the drawings I was after, did manage to find 11 of the 20 or so I was after. I got the entire wood roof for a 26 coupe, king pin, and 2 out of 3 26-27 front floor board drawings. Just not enough time to get everything on my list. I must have spent an hour looking for the spindle drawing.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Saturday, November 14, 2009 - 12:27 am:

Jeff
I really appreciate your efforts. I think I am going to be OK with the information I have. Time of course will tell. I am close to having the first one finished. A cast backing plate is going to be the answer, it will sure save a lot of fooling around.
We were in Denmark last spring and went to Legoland there. Quite the display.


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