differential narrowing jig

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clementine

clementine

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Whats your thoughts on differential narrowing jigs and rulers? I see that some cost upwards of 650 for the Mittler Bros setup and was wondering from someone who has the tools already...what you have...what you wish you had....and what is working for you. I am willing to drop cash on good tools but am hoping to glean some knowledge before diving in. I have a couple projects that need diff massaging. Might as well learn how to do it.

Thanks FABO!
 
I've done a few very successfully using the rear end itself as the setup tool. Had an old guy teach me how to do it years ago and it works very well.
 
Do tell. Is the solid bar necessary? It seems the general consensus is that many diffs are bent from the factory and during the narrowing process you weld new ends and straighten.......I would be giddy thinking I could narrow a diff without $600+ in tools.
 
So you are sourcing the rod locally and then buying the ruler and plugs via the intertube....correct? or rather ebay and summit etc.etc
 
I bought the set on Ebay from Ledmine also my set has 2 ruler plates and 2 sets of plugs one for 8 3/4 and the other for Dana 60. $204.99. I bought my1.25 shaft locally. Nice quality pieces, very satisfied. Worked excellent on my Dana 60 modification :thumbsup:
 
You don't need ANY of that stuff. NONE of it. By the time you are going back together with it, you will have figured out your new axle length and gotten the new axles. You'll HAVE the new ends. Figuring out WHERE to cut the housing is simple math. I'm not even goin there. Easy peasy. Once you're ready to assemble and weld the new ends on, mock it up loosely. With the ends in place and the axles and bearings installed. I take for granted at this point, you'll have the housing and ends prepped and angled to weld. The ends weld on with the horizontal center line of the ends parallel with the pinion center line. Easy. Using your hands you can feel for what I call the "sweet spot. That's where there is no binding whatsoever with the axle bearing. That's ALL you're after. That's ALL that 650 dollar tool does for you, is get the housing ends placed correctly so the bearings don't bind. Since the housing might be bent or warped a little right from the factory, just welding them on with the outer edges lined up ain't good enough. You need a reference coming off the differential carrier. What better tool to use than the carrier and axles themselves? Simply get the ends in the right place, buzz two points 180* from each other. That way, if you need to you can take a ball peen hammer and smack the end in a direction that frees it up the best. Once you got that down, weld er down. It's really THAT simple. I've done several like that and never had a problem. Not one.
 
grimreaper said:
I've narrowed a few using this setup with a 1-1/4" CR rod. It works well.
Rearend Narrowing Fixture Combo with Rearend Ruler - 8 3/4" Mopar Rear End - | eBay
Click to expand...

I have the same set up. I bought a 1 1/4 Cold Rolled solid bar from the local metal shop. I have done over 10 housings over the years. All of them were bent on the right (curb) side. At 200 a pop to narrow, it paid for itself quickly. I actually made the 8 3/4 pucks from aluminum stock when I worked in a machine shop. The one on eBay I bought for the Ford 9". They are super easy to use. I can narrow a housing in an hours time.
 
clementine said:
So you are sourcing the rod locally and then buying the ruler and plugs via the intertube....correct? or rather ebay and summit etc.etc
Click to expand...
Well, I actually ordered mine directly from Leadmine Products with a phone call several years ago, but he sells them on Ebay now. I bought the 1-1/4 rod from the local steel supplier. I know the guy there and asked him to give me a call when someone else wanted a partial stick.
I used to weld 'em up with no jig, similar to what Rusty describes, and never had one not run but the jig makes it easy to ensure all is good.
 
Hmmmm I don't recall my kit costs $650 :poke: ($204.99) small price to pay for precision
 
sabre67 said:
Hmmmm I don't recall my kit costs $650 :poke: ($204.99) small price to pay for precision
Click to expand...
Ya, that's the Mittler Bros kit off of summit. Has 9" Dana 60 8.75 etc etc puck, with the bar, but no rulers....
I have an s10 pickup 2wd that I'll probably get an 8.8 and try the RRR method.
 
When I narrowed the 10 1/4 corporate truck rear u simply used a plumbers pipe cutter to narrow the tubes, used Moser axle ends and tacked them in place.

Simple math got me the correct axle lengths. I narrow that rear 11".
 
grimreaper said:
Well, I actually ordered mine directly from Leadmine Products with a phone call several years ago, but he sells them on Ebay now. I bought the 1-1/4 rod from the local steel supplier. I know the guy there and asked him to give me a call when someone else wanted a partial stick.
I used to weld 'em up with no jig, similar to what Rusty describes, and never had one not run but the jig makes it easy to ensure all is good.
Click to expand...

I agree with this. You can definitely shorten the housings without the jig kit. But if you do it the way RRR suggests (which is fine!) you will have to disassemble and reassemble everything several times in the whole mock up/measuring/welding/set up stages. If you're going to shorten one housing and be done with it that's probably the way to go. But if you envision yourself shortening multiple housings you may want to invest in a jig. It makes the whole process shorter, all you deal with is the bare housing and the jig kit and there's no need to assemble and disassemble everything to get it done. The jig just saves time and makes things easier.

I bought a leadmine kit awhile back because they had a discount or something and I have several C body and truck 8 3/4 housings from the local yard that I may shorten for various projects. Still have to source the cold rolled bar but I can do that anytime. The Mittler Bros. kit is nice, but dang that's a lot of money.
 
Did the Leadmine kit with a couple of ends from Doctor Diff. Went fast and I think it was worth the investment.

mockup.jpg
finished rear.jpg
 
I cut an 8 3/4 down with the Lead Mine kit. Worked well plus I saved my A body 8 3/4 for future use.
 
Having trouble finding leadmine tools...out of biz? What is included in leadmine kit again?
 
check evay under Ledmine rear end narrowing. i was there this morning they have lots to chose from
 
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