View Full Version : Suggesting cutting bastard axles..

3 Phase Lightbulb
08-28-2005, 04:38 PM
I FINALLY got myself a nice pair of GM 28 spline axles out of a '96 Camaro Z28's rear end, but I'm having a very hard time cutting them... I thought they would just be case hardened, but they are hardened all the way through.. I burned out my 14" CHOP saw trying to cut one, so I'm not sure if I should just buy a better chop saw, or if there is something use I can cut these down with? The HF 4x6 saw only scratches these axles. I need to cut them down so I can weld on a custom pair of hubs that will bolt to my CV joints/axles.

If I should get a better chop saw, anyone have any suggestions on a really good heavy duty unit? My 14" china special lasted about 3/4" the way through before burning up the brushes.



3 Phase Lightbulb
08-28-2005, 04:41 PM
Here is what the Chop saw did before calling it quits:



08-28-2005, 05:11 PM
Adrian, the local engineering shop had the same problem with their h/duty saw when they cut my first Holden axle. We used plenty of flood coolant, slow speed and more load to get through the second one, and still the blade suffered http://bbs.homeshopmachinist.net//frown.gif. I would cut it with a cut off grinder then set it up in the lathe and machine the spigot and weld chamfer. If it is anything like my axle, it is damn tough! Once you get through the first 15mm, the core isn`t so bad to machine http://bbs.homeshopmachinist.net//biggrin.gif Plenty of hot blue swarf ! http://bbs.homeshopmachinist.net//smile.gif

08-28-2005, 05:31 PM
one word...oxy http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif

I had to cut some 1 1/2 induction hardened chromed bar with my bandsaw...It was tough going, but was soft in the middle...Turning the end of it for a thread was even worse...I burn't out 2 inserts doing it...

[This message has been edited by Ringer (edited 08-28-2005).]

3 Phase Lightbulb
08-28-2005, 05:38 PM
<font face="Verdana, Arial" size="2">Originally posted by Ringer:
one word...oxy http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif</font>

The axles don't have any pimples http://bbs.homeshopmachinist.net//smile.gif

The axle is about 1.5" in diameter.. I haven't tried O/A cutting yet.. I'm not sure my setup could cut that anyway.

Hurry up people, I need some answers before I go off and do something stupid like cut it with my bench grinder http://bbs.homeshopmachinist.net//smile.gif


Peter S
08-28-2005, 06:24 PM
I don't know what you call a 'chop saw', over here that usually refers to an abrasive cut-off saw, and that would handle it ok, just quite a bit of heat.

However...I would try a cut-off wheel in an angle grinder.

Use the thinnest you can get. Over the years they have got thinner, now we are using wheels about 0.8mm or maybe even thinner (about 1/32"). (This is for 4 1/2" grinder).

Thin means cooler cutting, you can do surgery with these things!

In case you haven't used cutting discs, they are generally flat, not depressed centre like grinding discs.

You will get some localised heating, not sure if this matters.

08-28-2005, 06:26 PM
Why don't you use the torch to heat the axles cherry red where you want to cut them and let them cool in still air. That should soften them enough to cut.

08-28-2005, 06:46 PM
Makita makes a good chop saw at reasonable money. The saw is not your problem however. Check the brand on your disk and you will find it is for short run steel (mild)like angle iron. What you want is a good grade like the type made by Makita for there saws. It will cut your steel just as easily as mild steel and coolant wont be necessary either. Price wise they are about 1/3rd more money but worth it.

3 Phase Lightbulb
08-28-2005, 07:14 PM
Sounds like maybe I just pushed my chop saw a little too far.. The blade was cutting well, but the motor was bogging so I tried to keep light pressure but the motor just burnt itself out after a few minutes..


3 Phase Lightbulb
08-28-2005, 10:34 PM
I actually found another pair of brushes for my chop-saw.. This cheap china special 14" cut-off saw came with an extra pair of brushes.. I finished cutting the first axle, and I'll just be more carefull cutting the other.



08-29-2005, 12:33 AM
Adrian...I cut big, hardened axles all the time with my 14" Delta chopsaw. If you just sit there chewing away it really burns up the blades. I cut with really sharp, short "chops"...raise the blade up and down into the cut intermitantly. When it hits I push pretty hard then let up and let everything cool for a sec then go after it again.
The 35 and 40 spline Strange axles are really tough but if you cut them like that it works pretty good.
If the blade glazes from too much heat it really slows the cut.
If I find a real hard spot...I just loosen the vise and give the axle a slight turn so the blade starts on a sharp corner.
Have fun!...It'll work!

3 Phase Lightbulb
08-29-2005, 12:43 AM
Thanks Russ.. I'll try your technique.

Now, how do you suggest I weld on my CV joint adapters? I'll be making a pair of hubs with bolt patterms that will bolt up to my CV joints out of 1/4" mild steel.. I was going to drill a hole in the 1/4" steel, slide the axle through the hole so it's flush, square it up, tack it in, then weld both sides. I've never welded anything to a driveshaft like this so do you have any advise?



08-29-2005, 01:33 AM
I'm curious about what cutting disc is being used. I use a 3 inch disc in my toolpost grinder, and the grit seems to be only in the first .030 or so of the disc. After it's worn off, the disc doesn't cut worth a damn. It surprises me that there isn't more abrasive on the edge. I don't know how the larger discs are made, maybe there's more active abrasive on the edge, so they would last through more cutting. My larger disc is an 8 inch cubitron, and that seems to cut just about anything and like it. I cut a section out of a transmission gear and didn't notice any reduction in the diameter of the disc. This part was about 6 inches diameter, and the thickness of metal about 5/16 inch, so that's a fair bit of all hard metal to grind away.

I realise Adrian that you didn't mention a problem with the disc, only the machine. That sucks, burning out a machine on one job. Maybe a better disc would make a difference, especially in a deep cut like you're doing. If there's less wear on the abrasive, the disc won't tend to jam in the cut nearly as much, and will take less power.

08-29-2005, 08:16 AM
3 Phase,

Looking at the last picture you posted with the differential in the upper left.

What is the purpose of the closely spaced teeth on the left side of the ring gear? They look too close together for a sprocket. Is there a speed sensor in the axle housing?


08-29-2005, 09:05 AM
I use cheap reinforced cut off wheels on my angle grinder to gut up end mills and drills that need to be shortened. The cut off wheels are cheap and so whast if you go through a couple in order to accomplish the task.

08-29-2005, 09:36 AM
If you will anneal the axels first you can cut them with a band saw.


3 Phase Lightbulb
08-29-2005, 12:05 PM
darryl, I'm using a cheap china 14" cut-off/chop saw. I bought it new last year off Ebay for around $20 or so.. I don't know what kind of blade it has, but I'm sure it's the same blade that all of the other cheap 14" china saws have. I forget the brand, but I think it has "American" something on the label http://bbs.homeshopmachinist.net//smile.gif

Winchman, that gear you see in the differential is a speed sensing gear. There is an electronic sensor that feeds the RPM back to the cars computer. I think they use that sensor for several things like MPH reading, Traction control sensing, etc. It's out of a 1996 Camaro Z28 so I'm sure you can get more info about it on the WEB.

Rustybolt, The 14" chop saw I have cost around $20 (I think the shipping costs were more expensive). They are disposable as far as I'm concerned. Mine is running great now with a new pair of brushes. I didn't realize initially that the saw came with a spare set until I found them close by.

KDRedd, I might try annealing... The Axle is about 1.5" in diameter so I'm wondering if I can really anneal something that large without significantly increasing the heat affected zone? Would an O/A setup with a rosebud be the best approach for annealing it?


Sine Wave
08-29-2005, 12:43 PM
Hi Guy's am new here so please feel free to jump on me if I say something stupid.

I cut a couple of hardened steel axles (from a scrap yard) on my own cheapie (Princess Auto)chop saw. Used the same technique as Russ (Torker). Sort of stab and release action.

Just wear your ear muffs and a jock strap.

08-29-2005, 01:53 PM
Adrian...if it was me making that I think I'd make a collar about an inch long and 1/4" wall thickness. Turn it down a tad on one end and make the hub a press fit or so. Then weld the hub to the collar while it is held in a press or vise. Will be a lot more accurate than trying to weld it square on the axle. Then press the collar/hub onto the shaft and weld the end and the bottom of the collar. I'd use 9018 if I had it...if not 7018 or T-91 dual shield. Preheat the works to 250 deg before welding...allow for slow post cooling.

3 Phase Lightbulb
08-29-2005, 02:04 PM
<font face="Verdana, Arial" size="2">Originally posted by torker:
Adrian...if it was me making that I think I'd make a collar about an inch long and 1/4" wall thickness. Turn it down a tad on one end and make the hub a press fit or so. Then weld the hub to the collar while it is held in a press or vise. Will be a lot more accurate than trying to weld it square on the axle. Then press the collar/hub onto the shaft and weld the end and the bottom of the collar. I'd use 9018 if I had it...if not 7018 or T-91 dual shield. Preheat the works to 250 deg before welding...allow for slow post cooling.

Thanks for the advice.. I'll build the collar/hub first, and see how that goes.. Are you suggesting I ARC weld them together with 7018 rod? I'd prefer to use my TIG machine unless you think I'll get better results on this heavy axle with ARC?


[This message has been edited by 3 Phase Lightbulb (edited 08-29-2005).]

08-29-2005, 03:16 PM
I got a buddy, Porky.. He has a Joker like scar over one eye. The Speed-cut wheel exploded as he walked into a friends garage hitting him across one eye cutting his eye, lid, eyebrow, and cheek about 1/4" deep. No insurance.

I paid his bills for a few weeks. He has paid me back ten times in brotherly love and labor since then. I bet I could call him to help me bury a body.

SO, be damn careful with any abrasive cutting wheel. Full face shield.

I used my port-a-bandsaw on the last axle I cut.

On casehardening? you take it heat it up red hot (my smelter) then stick it into some alum, (*pickling salt) and let it cool slowly. It'll suck the carbon right out of the metal and then it'll cut easily.

All tool steel is like this. Only way you can cut it.

I tried case-hardening some axles I had splined here. I had filed for three hours on them stinking things getting the gears to slide on. After heating them up and quick oil quenching them I got to file some more. The car they are in will pull a wheelstand.

ANOTHER TRICK from a old guy? paint a straight line down your axle from spline to bearing. I have seen them look like a candy cane and twisted up a turn and a half and not break. Change out the ones that look like that or eat a guardrail and fix sheetmetal.

08-30-2005, 07:25 AM
Adrian...LOL! That's what I said I'D do! I have a bunch of high alloy rod for the stick machine so I use it a lot. I preheat and can whack in a nice weld in shot with a 1/8" or 5/32" rod. Some of them I do tig though....it's just that I find stick is faster and I don't have to change wire on the mig.
By all means tig it. You have a good grasp on the process now (you have been practicing...right http://bbs.homeshopmachinist.net//biggrin.gif) and won't have any trouble. For this...I'd even preheat with tig as well. A very important step that a lot of people avoid.
David...good tip with the painted line on the axle. An old hotrod trick!
When I used to use full width Ford truck diffs in my rail, I used to do that. After every race, pull them out and check them....if they where twisted...just swap sides and twist them back. You could do this a couple of times before they'd snap. Amazing how tough they really are.

08-30-2005, 09:16 AM
I would use MG600 welding rod to weld the axles. This also good for welding springs and tortion? bars. As to annealing, heat to red and pack in lime and let cool for 24 hours.


3 Phase Lightbulb
08-30-2005, 10:16 AM
Ok, I'm screwed....I'll have to turn down the axle so I'm definitely going to have to soften it up like several people have suggested.. I'll probably turn them down to 1" after the spline.

I've never tried turning anything but alum and mild steel so am I correct in assuming that I won't be able to turn (and cut down) this axle in my lathe? Will carbide bits maybe cut it fine? Do I really need to soften them up?

I'll have to heat them with my O/A setup.. I have a Rosebud attachment -- Is that going to be sufficient? If so, any idea what PSI I'll need for Oxy/Acet? Can I just get the axle shafts glowing red without heating up the splines?

What are my options for "packing" them after I get them red hot? KDRedd mentioned packing in Lime.. Where do I get lime? Does it have to be pure Lime? Or will the Lime for lawns work? What other materials can I use?


[This message has been edited by 3 Phase Lightbulb (edited 08-30-2005).]

08-30-2005, 10:18 AM
Just a general statement about cut off wheels. With my cheap friction cut off saw, blade thickness makes a big difference 1/32-inch thinner blade cuts a lot faster and with less pressure. The grit being the same.
I have found some .011 thick blades for my 4 1/2-inch right angle grinder, they are impressive.