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ShawnG
ShawnG PowerDork
7/17/19 11:12 p.m.

So, I re-read the thread and maybe I missed it but why are you shortening it?

SkinnyG
SkinnyG UltraDork
7/17/19 11:30 p.m.

Not sexy:

Sexy:

SkinnyG
SkinnyG UltraDork
7/17/19 11:31 p.m.

And frankly, it's because that's what I want.

laugh

ShawnG
ShawnG PowerDork
7/18/19 12:55 a.m.

Seems perfectly reasonable to me...

SkinnyG
SkinnyG UltraDork
7/19/19 12:05 a.m.

Nothing to report. 

Swept up 10lbs of grinding dust.

Dragged the Eaton HO32 off to work to get it out of my face at home.

Stopped at a couple metal suppliers to see about a 4' x 4' sheet of 3/16" flat to make a step notch (about $175 CDN), then figured I could make the notch with a length of 4" flat I already had.  Duh.

Dragged the Ford 9" under the frame to determine where the notch will need to go.

Contacted a few suppliers for 9" axle shafts with the bolt pattern I want.  

759NRNG
759NRNG SuperDork
7/19/19 7:58 a.m.
SkinnyG said:

Not sexy:

Sexy:

Kant wait to see your metal shaping skills on the step 'shortening' wink and........yes this is WAY better

SkinnyG
SkinnyG UltraDork
7/19/19 7:14 p.m.

I temporarily mounted the 9" on the trailing arms. The top of the diff at full bump is no higher than the top of the frame rails, so that's good. I also ordered new axles with 5 on 5" pattern.....

There does not seem to be a dimension for where the mounts are to go on the axle; consensus seems to be "place them where they work best."

I picked up some 3/16" plate after all. After a fair bit of sitting and staring, I think I've come up with a notch I'm pleased with, though I may mock it up in cardboard entirely to see what I think.

Sharp corners are potential stress risers, so this is intended to reduce stresses. It also maintains a 4" tall frame through the notch as well. The front and back of the axle cut will use part of the original frame. It makes sense in my head.

Going to sleep on it before I bring out the plasma cutter.

Gtholen
Gtholen New Reader
7/19/19 8:28 p.m.

Have you ever been on the 67-72chevytrucks.com forums? There was a huge write up on step notches. Your photos and text reminded me of the thread. The guy who started the thread pretty much said the same as you did about stress risers and having a roll/curve in the notch design.  It was a good thread with a lot of data that was done with an engineering program. Either way I'm digging your truck.

Also Rob at No Limit uses a heavily modified 99-06 power rack in his conversions. Main thing he modified was the way the rack mounted on the one side. Seems like he cuts the one ear off and flips it and rewelds it.   

SkinnyG
SkinnyG UltraDork
7/19/19 8:40 p.m.

Cool about the rack, thanks.  Next time I'm at the wreckers I'll measure one and see how wide they are. I did discover some folks have made adapters to space the inner tie rods out a bit, which might work perfect to get the width I think I need.  On the other hand, snagging a GMT800 rack might be better, in that it can handle the pressure that the GM P/S puts out (the Ford needs the pressue reduced).

I've been frequenting the 67-72 site for years, and I know that thread. The biggest takeaway for me, was to maintain the frame height all the way over the notch.  Avoiding corners I knew already. On my '77 I did a pipe-notch and boxed the inside of the frame to make up for the cut - interesting to see how much strength the boxing did not put back into the frame.

Gtholen
Gtholen New Reader
7/19/19 9:32 p.m.

I figured you may have been on the site. Most C/10 guys have either heard of it or are members. Im 71'Tahoe on the forum. 

I like the idea of not having to reduce the pressure on the GM pumps. I have often wondered if there was any ill effects of restricting the pumps. I know the MII guys have restricted them for years so I guess there is no reason to doubt it.

 

SkinnyG
SkinnyG UltraDork
7/19/19 10:35 p.m.

I am (surprise surprise) "SkinnyG" on there.

SkinnyG
SkinnyG UltraDork
7/20/19 1:52 a.m.
SkinnyG
SkinnyG UltraDork
7/21/19 10:12 p.m.

Did a wack of yardwork yesterday, but got the sides of the notch plasma cut.

Interestingly, the smoke detector in the shop goes berzerk when I'm plasma cutting.  So I took it off the wall and put it in a cupboard.  Where it still goes berzerk! Makes you wonder what you're breathing, eh?? I started wearing a filtered mask a whole lot more.  My lungs feel better. Did I mention this??

Today I did a wack of surface prep so I can weld things together tomorrow.

Had to remove the crossmember immediately behind the axle so the side plates will fit. It will be reinstalled....

 

SkinnyG
SkinnyG UltraDork
7/22/19 7:03 p.m.

I brought out the plasma cutter.

The notches are fab'd, but not burned in yet.  Tomorrow they will be welded to the frame, then the frame braced, then the frame section cut out, then capped.

SkinnyG
SkinnyG UltraDork
7/24/19 7:32 p.m.

Notchos!

java230
java230 UltraDork
7/24/19 8:47 p.m.

In reply to SkinnyG :

Sweet!! 

NOHOME
NOHOME MegaDork
7/24/19 8:58 p.m.

That looks convincing.

 

Pete

759NRNG
759NRNG SuperDork
7/24/19 8:58 p.m.
SkinnyG said:

A good read:

Frame Notch Based On Strength

thanks for the info...cuz those onesided 'C' nothches  are in the grosh as I thread..... 

SkinnyG
SkinnyG UltraDork
7/25/19 11:51 a.m.

Second last crossmember is re-installed.  I suspect I'm going to have to move the rearmost crossmember to fit an '87+ 'Burb gas tank.

Welded-in trans crossmember is removed.  This is the old style, which holds the trans by the bellhousing, which won't work for, like, anything else.

SkinnyG
SkinnyG UltraDork
7/26/19 6:48 p.m.

Removed the trans crossmember, which is welded to the frame in the 60-62 and holds the transmission by the bellhousing.

Also removed the bottom of the center "X", as it is now the last things hanging below the frame. When I cut the 3/16" plates for the notch, I also cut out a new plate to replace this.

ShawnG
ShawnG PowerDork
7/27/19 12:08 a.m.

Looking good.

You should be able to ditch the steady bearing and use a one piece driveshaft now too.

SkinnyG
SkinnyG UltraDork
7/27/19 8:43 p.m.

Bottom of the frame is now plated, there is now nothing hanging lower than the frame rails.

And here it sits at what theoretically is ride height. The rear is based on axle clearance with new CPP 5" drop coils, not what they will settle to (probably another inch). Once the whole things is all together, I will trim and adjust accordingly.

Crossmember is 5" off the ground - that's a half-inch higher than my '77 sits, and the frame rails at the front cab mount will sit at 6.5" (an inch higher than my '77) but the rockers will be a half-inch lower than my '77. And everything hangs below the frame on the '77, nothing will on the '61 (so theoretically I could go lower).

The '61 is using 2" spindles instead of the 3" on my '77 - something I really wanted was to get the control arms off the ground. The truck will look lower than the '77, but it should be easier to drive with less collateral damage.

Oh, forgot to mention - I also flipped the trailing arm brackets to give back some anti-squat.

Gtholen
Gtholen New Reader
7/28/19 7:07 a.m.

I've got a 79' suburban tank in the shop if you need measurements. Notch looks good.

SkinnyG
SkinnyG UltraDork
7/28/19 11:34 a.m.

Apparently the 25 gallon is 28.75 x 28.125 x 10.75, and the 31 gallon is the same except 12.75 tall. The question I need to answer is if I want 150lbs of fuel hanging off the back, or 186lbs. Hmmm.  Now that I've done the math, why -wouldn't- I go for the 31 gallon tank??

I could possibly squeeze the 40 gallon 'Burb tank which is 37 x 31 x 9.9, for 240lbs of fuel hanging off the back.....

Since the bed floor will be raised 4", I should be able to tuck the tank up nice and out of the way.

SkinnyG
SkinnyG UltraDork
7/30/19 1:43 p.m.

I had to debate how to deal about wheels. The Jeep Grand Cherokee wheels that I have, have a fairly small center bore. I could bore the wheel out to fit the GMT400 brakes, or I could turn the hub down to fit the wheels.

I tried opening up the wheel center using some stacked hole saws and a wrist-breaker drill (I do not have a lathe than can spin an 18" wheel), but it went awful, and likely couldn't be balanced since the center was no longer true. That was a dumb idea. I don't know who thought that up, but what were they thinking?! I won't do that again (but I did correct the wheel center to be true again. Molested on the left, unmolested on the right).

The cut-to-length 9" axle shafts I ordered from East Coast Gear Supply have a hub diameter that is smaller than the Jeep wheels, so I cut the front hubs down to match the axle shafts.

In theory, once these hub/rotors are no good, I'll machine the rotor off, and use Grand Cherokee SRT8 rotors for a big brake upgrade.  It works in my head, dunno if it will work in real life.

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