Peerless 820 improved straight axle hub

I have a clutch abuse issue. So I had to design a new 820 locker. The typical 820 doc locker does not work for me as it does not provide enough axle key engagement. If you actually go and build this thing, please post yours. I'd love to see it. I will post pics of mine once it's completed.

Little tykes assembly


Here's the locker hub itself. You will want to use a full length 1/4" key for the axle. The two keys that transfer the load from the bull gear to the hub are 5/8" tall by 3/4" wide by about 1.3" long. I would have gone 3/4x3/4 but i didn't like how the bottom of the keyway got down into the 2" diameter.

It would probably be a good idea to tap a few set screw holes to stop the axle from sliding around in the case/locker. I would recommend tapping them where they will wind up underneath the side plates, so if they loosen up they can't really go anywhere.


Front view of the hub. Those two dimensions should be the same but mastercam is goofy and rounds things different ways. .0001" isnt an issue either way.


Right View


Here's the print for the keys, how I did them. I screwed up and made my hub too narrow and had to bolt the keys into the slots to center the hub in the carrier. Drill and tap hub for 1/4" socket head capscrews, and drill .1875" (3/16) for roll pin. Spacing same as key and centered on the center section of the hub. It's a nice idea to bolt the keys in but not necessary at all. You can just cut a piece of 5/8x3/4 about 1.3" long and stick it in the key slots



Personally I bored my factory side plates up to 2" to fit the locker, but I drew up new side plates anyway. NOTE that two of these are required, one with tapped holes and one with clearance holes.

Right view


Front view. The only thing critical in terms of thickness is the .094" dimension, it sets your side play for the bull gear.


Just for fun, here's some dimensions on the bull gear. 7DP is an odd pitch for gears, I figure the designers used it just because that's what tooth count they needed in a certain diameter to fit in the transaxle.

RichieRichOverdrive wrote:

as our good friend project farm would say: "Very Impressive!"

This is so cool! And so far above most of our heads haha

Whether or not you’re doing a fancy locker like me, through bolting is a must if you plan on putting any power through your 820

Literally the first thing I did post locker.  I don't think I changed the couple around the brake cutouts or not, but all the other were, and I did also install nuts on the opposite side.  I splurged a bit and used full threaded stainless bolts.

The only problems with socket head bolts is you have to clean the mud out of them to take them out lol. That was kind of a pain on my last disassembly.

Added the drawing for how I did my keys to the first post.

Figured I’d put all the build pics I got into one post.

First side drilled and outside turned


Gear fits


Boring first side


Second side in progress


Lathe work done


Truing up cast surface of side plate so I can hold onto them better


One bored side plate


Another side plate bored and what’s left of the original centers


Cut flats on the hub so I have something nice to hold onto and can just flip the part to do keyways 180* apart


Cutting keyway


Both keyways cut


Key bolted into bull gear with 1/4-28 SHCS with hole for roll pin in center


Center keyway cut in my shaper


Here you can see the tapped holes and roll pin hole for the key, as well as 4 of the 6 set screw holes. Two of these holes are over the keyway.


If you are building something this complicated for a mower you may have undiagnosed autism.


May as well leave my signature


In case with axle


Bonus information. There’s about .15” extra space between the hub and bearings. This also applies for the stock carrier setup. A pair of .07” thrust washers would leave .01” side play, but a pair of .0625” (1/16”) is probably more common and would leave a still reasonable .025” of play. Don’t shoot for 0 play, there has to be something.


The 820 case is right around 19 5/8” wide, this will hopefully help whoever is looking to figure the straight axle length they want.

@RichieRichOverdrive Hands down the best tool making and engineering work I've seen put into an 820 ever!

Thank you for the pictures, it makes the drawings much clearer. I could not figure this out the first time

"You will want to use a full length 1/4" key" as I thought you might have meant 3/4". Now I see what you meant with the set screws.

Thanks @Crazy_Carl I’m not in a hurry for once so I figured I may as well try to do a nice job of something lol.

@JB_4x4 glad that cleared something up for you. If you or anybody else wants any clarification on things don’t be afraid to ask. My drafting skills are just meh haha. I wouldn’t have even tried to draw all this stuff up if I didn’t want to share it with you guys. I’ve done more complicated stuff just off the top of my head working from memory hahaha.

That's the toughest looking piece of kit I've ever seen, great job and thanks for sharing so in depth with us!

Apiece of artwork thats a shame will be hidden!

Update after 9 months of pretty hard use: the locker has outlived a set of shift keys and the upper case of the trans it’s in. It’s being transplanted into a newer 820-040 with no changes to the locker.

You can see no shearing of the key here.

@RichieRichOverdrive Wow that's impressive.. I know you don't want to but I would love to see you bullet-proof a mst 200 series that would be awesome Lol

I have thought it over. When it comes down to it the case just can’t hold the power in. With a custom case with a 1” axle they would be fairly decent.