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Aldon

Opinions requested - Axle Pivot diameter

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Aldon

As some f you may already know I am in process of building a GT 14 with 22hp Predator and a widened 8 Speed tranny,

 

I have decided to use a swept front axle on it to widen it a hair and lengthen it as well.

 

The opinion I would like is this.

 

The swept axle and a 3/4 diameter axle pin and the GT 14 frame is set up for a 1 inch axle pin.

 

In either case, I will need to do some frame modification as the the swept axle is thinner from front to back when viewed from the top.

 

So if I go with 3/4 pin, I would either need to add a bushing in addition to moving the rear support brace forward.

 

If I bore the pin out from 3/4 to 1 inch, I still need to move the support brace forward.

 

I am leaning towards boring the axle out.

 

But wanted to see if anyone on the forum has experience to share that would add leverage to either plan or an altogether different option I have not yet thought of.

 

Regards, Aldon

 

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Ed Kennell

I would probably use  3/4 X 1"  flanged bronze bushings.  You may be able to buy the correct flange thickness so you wouldn't need to move the rear support.

  Or you could add a spacer washer. 

https://www.mcmaster.com/#standard-sleeve-bearings/=179okvr

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Achto

I think that I would bore the axle to 1" and shim the pin instead of moving the brace.:twocents-twocents:

Edited by Achto
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Aldon

Thanks fella's.

 

The difference is 1 inch. Meaning the GT14 is set up with front to back brace distance of 4 inches. or the thickness front to back of the axle at the pivot point is 4 inches.

 

The Swept axle is 3 inches.

 

As such, I am a little concerned in the unsupported  span of the 3/4 pin. Although the pressure should be transferred right at the braces.

 

Although the idea of using bushings and not having to relocate the braces is attractive.

 

The bushings seems to have ability to resist a lot of pressure but I imagine their tensile strength is questionable.

 

Onlyt real reason for concern is that I am already thinking of my next long term project of adding a loader and potentially a back hoe to this beast. But not sure I want to go through the extra hassle on a possible plan still in fuzzy stages.

Edited by Aldon
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Achto

I believe that if you use a 1" pivot pin with a 1/2" spacer on either side of the axle, that you will have no issue. The spacers could be steel, it would not have to be bronze or any other type of bushing material.  This would be a very short span for 1" stock as compared to how much axle sticks out of a transmission. My 867 has about 2" of axle showing between the trans and the hub. Granted the weight is transferred to two sides in this case but, I've seen a lot of weight hanging on the back of GT's with only 1" axles.

The shear strength of a 1" grade 2 bolt is 28,274lbs, grade 5 is 56,548lbs. Just some quick figures for you.

Edited by Achto
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Aldon

I agree. If only I had the ability to drill out the axle myself. Paying a machine shop makes that idea less desirable. I have a nice drill press but it needs several days effort and parts to get it functional and would still need to get a 1 inch drill bit.

 

Torn but leaning towards Flanged bearing idea. I can retrofit later if need be,

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Achto

Some more figs if you decide to go with 3/4" pin.

Shear strength of 3/4" bolt - grade 2 19,615lbs grade 5 31,808lbs

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Lee1977

Check the 1" hole in the frame it's most likely worn larger. Get a good 3/4 bolt or shaft and two 3/4" collars 1/2" thick. Line up the axle pivot and weld the collars inside the the axle brackets. I added a 3/4" collar to the front of the bracket on my C-120.

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Ed Kennell

Another change I make when rebuilding a front end is to replace the 3/4" pin with a  a  bolt and a nylock nut.  Then after I have assembled the axle with shim to close any gap, I can tighten the nut to remove any clearance.

 

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953 nut
1 hour ago, Aldon said:

Flanged bearing idea.

:handgestures-thumbupright:      :handgestures-thumbupright:

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oliver2-44

Oilies type flange bushings and spacers will have plenty of strength..Theu are also probable available at you hardware store.  if you were really worried about strength you could use hardened steel flange bushings but they woulf wear the pin and the axle  verses the beonze will wear (over a long time) but is easily replacable

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Lee1977

I revised my opinion. What I wrote before will put a lot of ware on a small area. Get some 1/2" plate to fit inside the frame locate your holes either 3/4"

or 1". drill the holes and weld the plates inside the original. Shape the plates to match the existing. This will give the axle more support. With 1" you'll have to drill the axle to but it will take a lot more to ware it out.

Edited by Lee1977
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WVHillbilly520H

@Aldon, from a machinist stand point a standard drill bit even in a milling machine normally drills oversize so with that being said if you were to overbore the axle for the best size hole it needs to be drilled 1/32-1/64" undersized then reamed to size .002-5" over also for something better than a standard cold roll steel pin "drill rod" is extremely tough but not hard as treated tool steel, and the oillite bronze bushings should be an acceptable gap fix as well as @Lee1977 above fix with the added plate for extra pivot brace strength, but with your budget and tools to fabricate things in mind using as many "off shelf" parts you can find might be your best bet (grade 8 Bolt ,flange bushings, and pivot brace/spacers welded in), Jeff.

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Aldon

I've decided to go with 3/4 pin. Ordered some stock this evening. The pin that came with the swept axle being a bit short. Will use several of the ideas provided to fab up a good set up.

 

thanks to all !

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roadapples

Whatever you decide, it will probably outlast most of us....

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fast88pu

I think it needs a custom independent front suspension on it. Just saying

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953 nut
24 minutes ago, fast88pu said:

independent front suspension

We can do this, twin "I Beam" like Ford pick ups used.    :ychain:

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Aldon

So I waffled back and forth but in the end, the 520 axle is straighter and the GT14 axle bracing would not work. So I had to cut them out and am in the process of fabricating up new brAckets or braces or whatever you call them. Then I will drill it for 3/4" pivot. The rest of this action will be in my GT22-8 thread.

Edited by Aldon
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Sarge

For reaming out axles , I use bridge or construction reamers with spiral flutes - they work well but it takes a pretty heavy drill press to handle them . That was the main reason I bought the old Atlas/ Clausing 18" production unit - it's nearly 5 times the weight of the 17" Crapsman I have here that will probably just get scrapped . 3/4" axle pins/spindles are pretty weak on anything bigger than a long frame 12hp tractor - adding a loader or any serious front weight will kill those small spindles/center pins in a hurry , just fyi . I do tend to overbuild things a bit , lol....but they last and my theory is to address it once , and be done with it .

 

Sarge

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Aldon

Have not sources the bits or tooling yet.

 

i do have this 20 inch drill press which I recently repaired and have operational.

IMG_0695.JPG.351e705e7fbb121b22c74e9e94826b24.JPG

 

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