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#2460599 - 03/03/18 05:13 PM small bolt pattern axles
dynamite Offline
pro stock

Registered: 01/02/07
Posts: 1402
Loc: NEW JERSEY
Can small pattern axles. be changed to 4.5 pattern , or do I need different axles. on an 8/3/4 rear ??

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#2460613 - 03/03/18 06:17 PM Re: small bolt pattern axles [Re: dynamite]
John_Kunkel Offline
I Live Here

Registered: 01/20/03
Posts: 19815
Loc: Rio Linda, CA
It has been done, the new holes get pretty close to the outside of the flange so it's a good idea to use screw-in studs.
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#2460658 - 03/03/18 08:33 PM Re: small bolt pattern axles [Re: John_Kunkel]
autoxcuda Offline
Too Many Posts

Registered: 01/20/03
Posts: 26051
Loc: So Cal
Originally Posted By John_Kunkel
It has been done, the new holes get pretty close to the outside of the flange so it's a good idea to use screw-in studs.



I’ve run a screw-in stud conversion since 1994. About 70K miles
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#2460672 - 03/03/18 09:18 PM Re: small bolt pattern axles [Re: John_Kunkel]
Cab_Burge Offline
I Win

Registered: 08/23/03
Posts: 31677
Loc: Bend,OR USA
Originally Posted By John_Kunkel
It has been done, the new holes get pretty close to the outside of the flange so it's a good idea to use screw-in studs.

iagree
I've had more than one set of A body 8 3/4 axles drilled and tapped for screw in studs to move and change the pattern to 5 on x 4.5 so we could use the stronger 1/2 inch studs and cheaper and easier to find wheels up
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#2460702 - 03/03/18 10:41 PM Re: small bolt pattern axles [Re: dynamite]
RapidRobert Offline
Circle Track

Registered: 11/20/03
Posts: 34399
Loc: Lincoln Nebraska
As said there ain't alot of meat to work with so go with the screw in studs. You would need lug centric wheels cuz the BBP wheel center hole will be bigger than the SBP axle register. You could fit a stiff fiberboard template with 5 ~7/16 holes and the center hole already cutout over the axle flange. make a pinprick for the center starting point in the template then 5 ~7/16" holes out on a 2" radius snug enough so the template will fit tightly over the current 7/16" studs then drill 5 new holes for the larger 1/2" studs. You want 5 pinprick marks equidistant around a 4.5" dia circle. figure where you want to locate the new holes correctly then make your first pinprick mark in the right spot then another 2.645" in a straight line tangent around the 4.5" circle then 3 more & the last one should be that same 2.645" distance then drill/tap the flange & drill the drum.
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#2460704 - 03/03/18 10:48 PM Re: small bolt pattern axles [Re: Cab_Burge]
SNK-EYZ Offline
master

Registered: 01/30/07
Posts: 8182
Loc: Lost in Space
Originally Posted By Cab_Burge
Originally Posted By John_Kunkel
It has been done, the new holes get pretty close to the outside of the flange so it's a good idea to use screw-in studs.

iagree
I've had more than one set of A body 8 3/4 axles drilled and tapped for screw in studs to move and change the pattern to 5 on x 4.5 so we could use the stronger 1/2 inch studs and cheaper and easier to find wheels up


I just had this done on a set of stock A-Body axles (8-3/4) at a guys shop that specializes in building custom rear ends.
With machining the axles for the screw in studs, installing new green bearings and drilling the drums it cost me $300.
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#2460731 - 03/03/18 11:59 PM Re: small bolt pattern axles [Re: SNK-EYZ]
Cab_Burge Offline
I Win

Registered: 08/23/03
Posts: 31677
Loc: Bend,OR USA
Originally Posted By SNK-EYZ
Originally Posted By Cab_Burge
Originally Posted By John_Kunkel
It has been done, the new holes get pretty close to the outside of the flange so it's a good idea to use screw-in studs.

iagree
I've had more than one set of A body 8 3/4 axles drilled and tapped for screw in studs to move and change the pattern to 5 on x 4.5 so we could use the stronger 1/2 inch studs and cheaper and easier to find wheels up


I just had this done on a set of stock A-Body axles (8-3/4) at a guys shop that specializes in building custom rear ends.
With machining the axles for the screw in studs, installing new green bearings and drilling the drums it cost me $300.


We use to pay $25.00 a axle plus the screw in 1/2 inch allen studs, my how I miss those days whiney We would drill our own drums also to keep cost down, I always made those new stud holes a little bit bigger and use the drum centering ring to locate the drums on the axles up
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#2460770 - 03/04/18 07:27 AM Re: small bolt pattern axles [Re: dynamite]
NachoRT74 Offline
master

Registered: 08/14/07
Posts: 5101
Loc: Caracas, Venezuela, SouthAmeri...
If you are going to install green bearings, I'd get the new replacement aftermarket axles which are made just right for that to A Bodies Small bolt pattern conversion to big bolt pattern removing the thrust block. Doesn't make sense to keep the original ones converted.

A friend of mine BELIEVE IT OR NOT, cut the hub from B body axles donor, cut the hubs from his own A body axles and installed the ones removed from the B body ones. He made splines on axle to fit the B body hubs by pressure and also seam welded those. He ran at 1/4 mile races for long time with that on his 70 Swinger.

That's something tipically done down here when fixing heavy duty trucks axles.

Just an idea if you wanna try it. Can't tell the cost of that kind of job up the or even if you take care of doing that.


Attachments
IMG_0790.PNG




Edited by NachoRT74 (03/04/18 07:32 AM)

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#2460857 - 03/04/18 10:17 AM Re: small bolt pattern axles [Re: dynamite]
BDW Offline
master

Registered: 05/12/05
Posts: 3550
Loc: Florida
How much are new axles? If your paying $300, I think I'd prefer something exact.

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#2460921 - 03/04/18 12:06 PM Re: small bolt pattern axles [Re: BDW]
B5 Bee Offline
master

Registered: 02/28/03
Posts: 8020
Loc: Pangaea
Last set I had done, I took to the machine shop.
Machinist put them on a lathe, scribed a 4" circle, drilled and tapped 1/2"x20 every 72*.
This was back in the early '80s when new axles were about the same cost as they are now, $300. Lot of $$$ back then.

Best reason to buy aftermarket axles, you can have 10"x2" or larger brakes. With OEM 4" on 5 axles, your stuck with 10"x1.75" or smaller brakes.

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#2460965 - 03/04/18 01:33 PM Re: small bolt pattern axles [Re: B5 Bee]
SNK-EYZ Offline
master

Registered: 01/30/07
Posts: 8182
Loc: Lost in Space
Roughly $100 of the cost was the green bearings and installing them.

Since one of the original bearing felt rough when spinning the axles needed bearings.

Originally he was talking $150 to drill the axles to change the bolt pattern to 4.5 but he wanted to use Chevy studs because the use a smaller knurled diameter.

I wanted 1/2 inch studs, so that meant screw in studs to keep the diameter smaller.

I wanted the ability to go back to the original 4 inch bolt pattern in the future because at some point the car will be restored since it's a factory 383 car.
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#2461093 - 03/04/18 05:03 PM Re: small bolt pattern axles [Re: NachoRT74]
John_Kunkel Offline
I Live Here

Registered: 01/20/03
Posts: 19815
Loc: Rio Linda, CA
Originally Posted By NachoRT74

A friend of mine BELIEVE IT OR NOT, cut the hub from B body axles donor, cut the hubs from his own A body axles and installed the ones removed from the B body ones. He made splines on axle to fit the B body hubs by pressure and also seam welded those. He ran at 1/4 mile races for long time with that on his 70 Swinger.


Fairly common back in the day, just bore the flange from both axles, press the SBP shaft into the BBP flange and weld at the outer end of the shaft. Henry's Axles, one of the first custom axle suppliers did it that way. As strong as the original when done properly.
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#2461114 - 03/04/18 05:39 PM Re: small bolt pattern axles [Re: dynamite]
NachoRT74 Offline
master

Registered: 08/14/07
Posts: 5101
Loc: Caracas, Venezuela, SouthAmeri...
Cool!

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