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3 Phase Lightbulb
08-17-2005, 11:22 PM
Anyone have a pair of 28 spline GM axles that they don't need? I'm looking for someone that wants to cut me a pair of 10" axle stubs (28 spline on one end). If you want to cut the hub off at 10" too that would be great.. Ie: (2) 28 spline stubby axles (10"), and two stubby hubs (5 bolt hubs, with 10" axles)

-Adrian

abn
08-18-2005, 01:02 AM
Aren't axle splines standardized?...In other words an involute 28 spline is an involute 28 spline GM or Ford or any other domestic?

3 Phase Lightbulb
08-18-2005, 01:10 AM
That would be cool, but I'm not sure if a GM 28 spline is the same cut and diameter as a Ford 28 spline.

I have a new GM 7.5" Torsen diff rear end I need to make a pair of stubby axles to attach a pair of Type-4 VW/Porsche 924 CV joints to.

-Adrian

topct
08-18-2005, 09:44 AM
3ph, thanks to your questions, my questions have been answered. My application of one of those diffs is much simpler than yours. I can just use a couple of shortened straight axles.

But I think you might have a problem with what your trying to do. Straight car axles are only supported on the outer ends by a single bearing. The splined end is supported by the spyder gears in the diff.

If you were to try and run a half shaft with cv joints on both ends there needs to be more support on the wheel end than one bearing.

I would look for a GM front drive or rear IRS setup and use either thier outer axle carriers (they use two fairly beefy bearings) or make your own using their bearings and outer axles. You would still need to adapt the Porsch cv joints to the GM stubs. But you will have the support you have to have on that outer axle.

At that point you could also use their brakes if you wanted.

Of course if you already know this and are making plans for another bearing out there, disregard my advice. Just remember to use tapered roller bearings in place of the ball bearings that are used with a straight axle.

And you are going to harden up that Susuki clutch I hope?

------------------
Gene

3 Phase Lightbulb
08-18-2005, 10:48 AM
<font face="Verdana, Arial" size="2">Originally posted by topct:
3ph, thanks to your questions, my questions have been answered. My application of one of those diffs is much simpler than yours. I can just use a couple of shortened straight axles.</font>

What kinds of projects have you built using shortened straight axles?


<font face="Verdana, Arial" size="2">Originally posted by topct:

But I think you might have a problem with what your trying to do. Straight car axles are only supported on the outer ends by a single bearing. The splined end is supported by the spyder gears in the diff. </font>

Yup, my plan is to hold my 7.5" carrier inbetween my buggy's frame with a pair of sealed bearings. The mini splined shafts will go into the carrier, and will also have one bearing next to the carrier bearing for the stubby axles. At the end of the stubby axles, I'll weld on a hub with the same bolt pattern as my Type-4 CV joints. On the other end of the CV joint I'll build another pair of stubby 1" axles with 2 bearings holding the axle in my trailing arm (about 4 inches apart). So to put it all together starting from the carrier down to the wheel on one side:

&lt;Carrier&gt;
&lt;carrier Bearing&gt;
&lt;axle bearing&gt;
&lt;stubby Axle&gt;
&lt;Axle hub with CV bolt pattern&gt;
&lt;Type-4 CV Joint&gt;
&lt;Splined Axle&gt;
&lt;Type-4 CV Joint&gt;
&lt;Axle hub with CV bolt pattern&gt;
&lt;1.25" OD stubby axle&gt;
&lt;1.25" ID Inner bearing&gt;
&lt;4 inches of space&gt;
&lt;1.25" ID Outer bearing&gt;
&lt;1.25" OD Output shaft with 1/4" keyway&gt;
&lt;Custom wheel hub with wheel lugs&gt;
&lt;Wheel&gt;


<font face="Verdana, Arial" size="2">Originally posted by topct:
If you were to try and run a half shaft with cv joints on both ends there needs to be more support on the wheel end than one bearing.</font>

I plan to support the output shafts (short 1.25" OD axles) with a pair of bears about 4 inches apart..The bearings will go into my trailing swing arms that I plan on making.


<font face="Verdana, Arial" size="2">Originally posted by topct:
I would look for a GM front drive or rear IRS setup and use either thier outer axle carriers (they use two fairly beefy bearings) or make your own using their bearings and outer axles. You would still need to adapt the Porsch cv joints to the GM stubs. But you will have the support you have to have on that outer axle.</font>

I'm basing my design on the IRS setups, except I'd like to fabricate my own output axles, outer axle bearing carriers, trailing arm, etc. I think I'll have more fun fabricating those even if the IRS components are much better.


<font face="Verdana, Arial" size="2">Originally posted by topct:
At that point you could also use their brakes if you wanted.</font>

I'm probably going to bolt in motorcycle rotors inbetween the CV Joint, and the output axle hub down near the output bearing carrier. I will have front disc brakes so I'm still not decided if I'll go with rear brakes.


<font face="Verdana, Arial" size="2">Originally posted by topct:
Of course if you already know this and are making plans for another bearing out there, disregard my advice. Just remember to use tapered roller bearings in place of the ball bearings that are used with a straight axle.
</font>

I was planning on using two sealed 1.25" ID bearings 4 inches apart inside my bearing carrier. I think the sealed bearings are ball bearings but I'm not sure. What is the advantage of roller bearings for my application?


<font face="Verdana, Arial" size="2">Originally posted by topct:
And you are going to harden up that Susuki clutch I hope?</font>

For now, I'll just run with the stock clutch and get the buggy rolling. If I detect any slipping I'll install a better clutch pack and stiffer springs. I'm going to be running a much larger sprocket in the rear so that will help offset the additional torque needed to get her moving. I don't plan on driving the buggy at high speeds &lt; 60 MPH so a nice large rear sprocket will also help me keep the engine in the happy 7-8K RPM range.

-Adrian

topct
08-18-2005, 12:33 PM
3ph, the project I have in mind is a small replica of a Harley 3 wheel servi-car. I haven't done anything yet except try to find a solution for the differential that it will need.

I used to work in a motorcycle salvage business and was involved with buying and selling used bikes and parts. I sold all kinds of motorcycle stuff to guys that were kinda on the same track as yourself. Saw some pretty clever stuff. And there was a repair shop downstairs with a few mechanics that in their spare time would try to build all kinds of motorcycle engined bikes/vehicles. It was a tweekers paradise.

That's what keeps me looking for off the shelf solutions.

By your description it sounds like you have the a major part of one of these figured out. The drive. and getting it to the wheels. This has been a weak link in a lot of projects like this, with most going for a solid axle. And suffering the steering at low speeds problem. The differential, even a simple one really makes a differance.

As to your bearing question. Some heavy duty ball bearings might work in this situation. But I would consider the side loads that are going to be put on them. I think tapered bearings, in a size like you describe, and in a car this light, would probably eliminate any problems there.

Show us your progress, and good luck.

One note, that 4 wheel atv reminded me of one the things I sold parts to a guy for. A Honda 250r 4wheel chassis and suspension with a VFR750RR Honda engine in it. It wasn't just insane, it was also pretty much impossible.

------------------
Gene

3 Phase Lightbulb
08-18-2005, 01:51 PM
Does anyone know if a GM 7.5/7.625 28 spline Zextel Torsen gear driven locker differential will accept both GM 28 spline axles, and Ford 28 spline axles? I need to find a pair of axles on Ebay with the right splines.

Anyone know the difference, if any, between ford/GM 28 spline axles?

-Adrian

torker
08-18-2005, 08:21 PM
Adrian...perhaps another avenue for you...what we used to do with IRS racing buggies. Use a Four wheel drive front hub assembly(for your rear wheel drive)...use the axle that sticks out (duh) with the U joint. Make your other shaft with the same U joint flange...and a CV joint where it enters the diff. Some of the Suzuki etc. hub units are pretty light.
Russ

torker
08-18-2005, 08:25 PM
Aslo...I'll look arounf and see if I still have a GM 28 spline axle kicking around and see how it fits into a Ford 28 side gear.
Another thing...mabe Email Strange Engineering...they could tell you this quick!
Russ

CCWKen
08-18-2005, 08:53 PM
It depends on what the axle came out of or for. Not all 28-GM equal 28-Ford. In fact not all GM-28's are the same. The diameters and pressure angles on some GM's are different for the same spline count. The only spline count swap would be in the GM 10 bolt 8.5 & 8.2 before '82 and the Ford 9.0 & 8.8 diffs. But neither of these will fit your diff. The diameters are different.

Are you sure your spool is 28 spline? The 10-bolt 7.5 diffs (82 and up) were 26-spline, I believe.

[This message has been edited by CCWKen (edited 08-18-2005).]

torker
08-18-2005, 08:55 PM
<font face="Verdana, Arial" size="2">Originally posted by abn:
Aren't axle splines standardized?...In other words an involute 28 spline is an involute 28 spline GM or Ford or any other domestic?</font>
I don't think axle splines are involute.
Why would they be? They don't rotate around anything. They sit still in the side gear/spool. I just looked at a bunch of axles and the splines look like a 90 deg spline to me...nothing more.

CCWKen
08-18-2005, 09:01 PM
Most of the pressure angles are 30 or 45 degree. Or 60/90 as in your observation.

3 Phase Lightbulb
08-18-2005, 09:36 PM
Here is a description of my diff:


<font face="Verdana, Arial" size="2">
NEW GM 7.5" & 7.625" Zexel Torsen Gear Driven Locker. Will fit a 3.23 ratio and up. Works with all GM applications using a 7.5" or 7.625" ring gear and 28 spline axels. This is a sturdy built locker and would work great for racing/street rod applications. </font>

Here are some pictures of the unit:

http://www.bbssystem.com/buggy/torsen1.jpg

http://www.bbssystem.com/buggy/torsen2.jpg

I think S10 axles should work, 6-cyl Camaros, etc.. I assume any GM 28 spline axle will work, but it looks like some axles use retaining clips, and some use bolts? Can you use either/or? Or do some diffs only have room inside for a retaining clip, and some can use a retaining bolt/washer?

-Adrian

3 Phase Lightbulb
08-18-2005, 09:40 PM
<font face="Verdana, Arial" size="2">Originally posted by torker:
Adrian...perhaps another avenue for you...what we used to do with IRS racing buggies. Use a Four wheel drive front hub assembly(for your rear wheel drive)...use the axle that sticks out (duh) with the U joint. Make your other shaft with the same U joint flange...and a CV joint where it enters the diff. Some of the Suzuki etc. hub units are pretty light.
Russ</font>

I was thinking about that myself, but I couldn't find any good front differentials that locked. I found that nice light NEW Zextel Torsen locker and have based everything off that, but if I had found a nice front diff w/CV joints that was a locker I would have bought it..

-Adrian

torker
08-19-2005, 12:53 AM
Adrian...I meant just use the hub assembly for your outboard drive. We used to build equal length A arms...mount the 4wd spindle/hub to that and couple them to a VW transaxle. Was easy to do and cheap. The smaller 4wd stuff is pretty light and you can lighten up the disc brakes a lot by drilling them. We used to get these Thunder buggies up over 100 mph on dirt tracks...tons of air flying over jumps. I don't have a GM axle on the place anymore but I think Ken is probably right about diameters etc. I'll check...some of the 4wd stub axles may use this spline..that'd be super easy...just get two 4wd stub axles per side...it may be worth checking out. Come up for coffee and we can take a trip out to the dump and see if there are any!
Russ

abn
08-19-2005, 01:13 AM
Torker...that's a great question. I don't know, and I haven't had the gumption to find out "why". All I do is parrot what I read, and try to retain enough to keep me out of trouble when I go parts swapping:

"All OE axles, differentials, and so on, have involute splines,"

from:

http://www.markwilliams.com/technical/schmaxles/index.html

and of course what I read here:
http://bbs.homeshopmachinist.net//Forum1/HTML/002141.html

http://bbs.homeshopmachinist.net//Forum1/HTML/007609.html

http://bbs.homeshopmachinist.net//Forum1/HTML/010685.html


<font face="Verdana, Arial" size="2">Originally posted by torker:

Originally posted by abn:
Aren't axle splines standardized?...In other words an involute 28 spline is an involute 28 spline GM or Ford or any other domestic?</font>
I don't think axle splines are involute.
Why would they be? They don't rotate around anything. They sit still in the side gear/spool. I just looked at a bunch of axles and the splines look like a 90 deg spline to me...nothing more.

torker
08-19-2005, 02:10 AM
abn...The axles I looked at where all high mileage used axles. A 90 deg (included) cutter fits perfectly, even under 6 power (all I have) magnification. I've never thought to look at a new axle but I'll be able to soon as I have a set on the way soon.
When you read the MW article...did you notice that they say "The ONLY way to cut involute splines is with a hob" That's crap...I could cut them with an involute cutter.
Russ

3 Phase Lightbulb
08-19-2005, 10:11 AM
I'm starting to wonder if my diff really has 28 or 26 splines... I'll have to wait until I have it in front of me. It's being shipped to me UPS right now.

Until I know for sure, please don't start taking apart your daily drivers and cutting up your axles for me yet... http://bbs.homeshopmachinist.net//wink.gif

-Adrian

merf23
08-19-2005, 06:51 PM
I believe the 1990 and up gm 7.5's are 28 spline, the earliers are 26. Most of the torsen for sale that are cheap are OEM units out of late model camaros/firebirds and are 28 spline. Torsens were not an option during the 26 spline years.

3 Phase Lightbulb
08-19-2005, 07:09 PM
<font face="Verdana, Arial" size="2">Originally posted by merf23:
I believe the 1990 and up gm 7.5's are 28 spline, the earliers are 26. Most of the torsen for sale that are cheap are OEM units out of late model camaros/firebirds and are 28 spline. Torsens were not an option during the 26 spline years. </font>

I think that explains it. I was looking for axles on Ebay and found a bunch of 26 spline but they were from the mid 80's. I'll try looking for 1990+

-Adrian

CCWKen
08-19-2005, 07:55 PM
I thought so. Thanks for the jog, Merf. I just needed to get them ole trucks out of my cobwebs and join the 21st Century! http://bbs.homeshopmachinist.net//biggrin.gif

3 Phase Lightbulb
08-23-2005, 02:48 PM
I got my GM 7.5" & 7.625" Zexel Torsen differential and it's actually quite a small compact unit. It's small enough to fit in the palm of my hand. It does have 28 spline axles so now I need to find a pair of 28 spline axles to cut up.

The outside bearing seats measured 1 5/8" OD so I bought a pair of these flange bearings (1 5/8" ID) that I plan to use to hold the differential in the buggy with:

http://www.bbssystem.com/buggy/flange_bearing.jpg

They were very cheap at $14 each on Ebay.. I've never used this type of bearing before and was wondering if it would be sufficent for holding the differential in place? The bearings are longer than they need to be so I was also planning on putting another bearing inside the main bearing to support the axle stubs.

Does anyone have any experience with these types of flange bearings?

-Adrian

tattoomike68
08-23-2005, 03:24 PM
((Does anyone have any experience with these types of flange bearings?))

Its a good bearing , I have seen them used in AG work where they run in the dirt at slow speed , but am not sure as to how well it would work at high speeds, it is worth a try for sure.

If you wear it out thats ok it means you had a good time. http://bbs.homeshopmachinist.net//smile.gif

also I think the grease zerk is the press in type you can tap it 1/8 npt if it is not.

[This message has been edited by tattoomike68 (edited 08-23-2005).]

CCWKen
08-23-2005, 03:26 PM
That should do it. The 4-bolt flange bearing should be stronger than a pillow block style. Just make certain you mount them so the differential can be installed/removed easily. Like bolting to the INSIDE of your differential carrier frame. (Pull the axles, undo the bolts and the diff drops out.)

One thing you might check--See if there's a small hole in the bearing race. A lot of the pillow blocks I've been getting lately don't and the grease fitting is just for show.