Torsk (Backbone Chassis) Kart

[Functional Artist]

Pretty much the same procedure for the (2) rear batteries
...only this time, I drilled (2) pilot holes (in opposite corners)
...this way I could cut (2) ways from each pilot hole

No surprises this time

Came out pretty good, a little wavy here & there
...a quick clean up with a flap disc smoothed 'er out nicely

It didn't seem to loose any rigidity, with the cut-outs.
It still feels as strong as before
...even with the batteries in place

 

[Functional Artist]

While I had the jig-saw out I figured that I might as well, cut the (2) cut-outs for the front axle

I thought twice about doin' it, before I did it

I was/am worried about turning the backbone into Swiss cheese

* I could cut & weld on separate 6" axle stubs on each side

Naw, lets just stick with the original plan
...it should actually be stronger with the one piece, thru axle
...& easier to square up the (2) sides

Yup, that looks good to me

...even, came out, nice-n-square

 

[Functional Artist]

Before I break out the welder, I wanted to get the rear of the backbone prepped

So, I used the rough grinder to remove most of the unwanted material & to help establish the main "curved in" shape
...then, the flap disc to get 'er all cleaned up
...& the axle housing too

Time for some welding

Made sure everything is nice-n-square
...tacked 'er together
...double checked the squareness, again
...& welded 'er on good-n-solid

 

[Functional Artist]

I also
...inserted the front axle thru the backbone
...centered, with 6" on each side
...made sure everything was nice-n-square
...& threw a couple of beads on each side, to lock 'er in place

Startin' to take shape

 

[landuse]

Looking good!!

 

[Nosandwich]

 

[Functional Artist]

Next, I am gonna work on the trailing Arms (not really cause they don't trail)
More like Rear Axle Housing support/Bearing mounts

Using (2) pieces (one for each side) of 3" x 1/8" flat steel ~20" long
...the bearing are to be mounted at the rear edge of each piece

Could go diagonal or horizontal

I'm goin' horizontal
...to keep the mounting bolts centered, not at the edges

So,
...find & mark the center of the 3" steel
...place the bearing holder & mark the center hole & both bolt holes
...found the middle of the center hole & used a spring punch to mark the spot for drilling
...& drilled it out with an 1/8" bit

I am only working on the center hole(s) right now, we'll get to the bolt holes later

Then, I stacked the (2) pieces & clamped them together with vise grips
...& used the top piece as a template to drill them both the exact same
...drilled them both out with standard drill bits up to 1/2"
...then used a step bit to drill them out to 7/8"

But, the outer edge, of the center, of the bearing is ~1 1/4"
...so, were gonna have to drill 'er out to ~1 3/8"

 

[ezcome-ezgo]

Should have gone from pilot hole to hole saw maybe?

 

[Functional Artist]

Should have gone from pilot hole to hole saw maybe?

I thought about it.

Hole saws tend to dance around a lot on flat steel, even with a tight pilot

I was hoping for a little bit cleaner holes

I got some bigger HF step bits

 

[Functional Artist]

Harbor Freights "bigger" step drill bits just happen to go up tp 1 3/8"
...used a little cutting oil to help keep 'er kool

Yup, we got some nice 1 3/8" holes
...then, added the bolt holes

Held 'er up to the rear axle housing
...everything still looks good

Next, I gotta make some spacers
...so the bearing holders can sit solid & flush against the trailing arms

 

[Functional Artist]

Now, for Rear Axle Bearing Spacer Blocks

The way these bearing holders are designed, there is a lip on each side, that cups the bearing.

That lip is ~3/16" lower than the bolt flanges.

So, we need spacers between the bearing holder & where they mount on the trailing arm.
...they need to be ~3" x 4" & ~1/4" thick
...with a ~1 1/2" center hole & 5/16" bolt holes


They could/should be made out of steel but,
...trying to keep the weight down
...& boring 1 1/2" holes thru 1/4" steel ain't so easy

I have some plasti-wood I guess you would call it (plastic board with wood fibers) that's pretty sturdy & ~1/4" thick that I am gonna give a try.

Here is where a hole saw comes in handy
...the 1 1/2" saw is just a hair bigger than the bearing flange
...& walked right thru the material with ease
...ran 'em thru the table saw (a few different directions)

Boom! Light weight bearing spacer blocks

 

[Functional Artist]

The Bearing holders sit nice-n-flush in/on the spacer blocks
...the spacer blocks sit nice-n-flush on the trailing arms
...& the trailing arms sit nice-n-flush on the ends of the rear axle housing

 

[ezcome-ezgo]

So are you welding the "trailing arm" to the tube?

 

[Functional Artist]

So are you welding the "trailing arm" to the tube?

Yup, once welded together
...the axle will run thru the axle housing
...& thru each bearing, on each trailing arm

It will all be (1) unit
...welded to the end of the backbone chassis
...with additional support (to the rear axle housing) provided by the trailing arms, that are connected (further forward) to midsection of the backbone

 

[Functional Artist]

Here is how the "trailing arms" are designed to function

Each trailing arm is to be welded to each end of the rear axle housing
...bent @ ~45* angle, in toward the backbone
...& also, welded back to the chassis. (triangulation)

This should/will give us
...a place to mount the bearings
...provide additional support to the rear axle housing
...& a solid support to mount the motor mount plate on/accross to

Had to "dry fit" everything together to get the dimensions/measurements for the bends

This 2 1/2" wide steel is too wide for my bender
...so, I'll have to get creative

Clamped the trailing arm down @ the bend line(s)
...(1) 45* bend @ 9" from the rear
...(1) 45* bend @ 18", leaving a ~2" (welding) tab

Vise grip/clamped a ~2' piece of 2" x 2" angle iron to it for leverage
...& bent them both to roughly match

Yup, that's pretty close to what I had in mind

 

[Functional Artist]

More pics of the trailing arms

Time for some clean-up & some weldin'

 

[ezcome-ezgo]

Cool. This is interesting.

 

[Functional Artist]

Trimmed up the spacer blocks a bit
...then, used them to mark the trailing arms

Cut (1) of the trailing arms @ the mark
...then, clamped the (2) trailing arms together, with vise grips
...& then, cut the other trailing arm to match

I also trimmed the welding tabs down ~1/4" on each side
...because, if ya remember, the backbone is only 2" wide
...& the trailing arms are 2 1/2"

This way they'll match up better

 

[Functional Artist]

Now for some cleanin'

Marked the area where the trailing arms will be welded to the backbone & cleaned 'er up with a flap disc
...& the trailing arms too

Clamped the trailing arms in place
...making sure the center hole is centered with the inside of the axle housing
...also centered on/with the backbone
...& then, flipped 'er over for easier welding

Yup, it looks like we got some penetration

 

[Functional Artist]

After welding all the way around the axle housing, I double checked the distance
...between the backbone & the trailing arm at the axle housing
...& further forward to ensure they were parallel

Then, welded the front of the trailing arm on by filling in the holes for like "spot" welds
...& a quick zip across the end too

Double checked all measurements & welded the other one on, just the same

I almost like the rustic/industrial lookin' spot welds better

Seemed to have come out pretty square