will the fixture table fold?

mobil1syn

mobil1syn

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i want to build an fixture table for a project that will serve two purposes
  • a workable fixture table
  • a structural member in the event i need to straighten an axle housing

so with that in mind i am doing comparison engineering since i cant do real engineering. is there sanity in my thought process or am i missing something in my simplistic brain?

so an s10x25.4 ibeam has the following specs from the internets
1752029123172.png


an ibeam calculator says that with a midpoint load of 20k lbs i will see less than 1/16" of deflection
1752030422579.png


so since i have no knowledge on how to use solidworks for simulations, i am just do some comparison engineering

6' - s10x25.4 mass properties via solidworks vs my fixture table, so one could argue that my fixture table is significantly stronger than the ibeam that would deflect less than a 1/16" of an inch with that 20k load.
1752029607167.png
1752029759607.png


table is 12"x16"x6" - 12" wide outer portion is 1/4", everything else is 3/16". the fixturing orientation would be open side down, structural orientation would open side vertical
1752030059791.png
 
SLOWPOKE693 said:
How many bent housings do you plan on straightening??? Especially being a 12" X 16" table. :confused:
Click to expand...
I would think that once one is bent, it’s weaker now after being straightened also my thoughts. Unless you weld trusses on it after straightening

How much more work would it be in just replacing the tubes with new ones? If cast turd housing, is it stressed cracked in areas you can’t see easily?

I remember back in 79-80 when I work on small engines, we used to remove the crankshaft out of the engine and straighten them on V blocks in a press measuring with a dial indicator. Towards the end of my time there, they suddenly stopped doing it and would only sell a new crankshaft or engine. Apparently one broke on a customer and that was the end of that. Cool story I know.
 
Landslide said:
I would think that once one is bent, it’s weaker now after being straightened also my thoughts. Unless you weld trusses on it after straightening

How much more work would it be in just replacing the tubes with new ones? If cast turd housing, is it stressed cracked in areas you can’t see easily?

I remember back in 79-80 when I work on small engines, we used to remove the crankshaft out of the engine and straighten them on V blocks in a press measuring with a dial indicator. Towards the end of my time there, they suddenly stopped doing it and would only sell a new crankshaft or engine. Apparently one broke on a customer and that was the end of that. Cool story I know.
Click to expand...
Chinese imports is what happened. Cheaper to buy a new over seas crank than pay somebody half hour wages to straighten it.

Same reason damn near nobody turns drums and rotors anymore
 
Provience said:
Chinese imports is what happened. Cheaper to buy a new over seas crank than pay somebody half hour wages to straighten it.

Same reason damn near nobody turns drums and rotors anymore
Click to expand...

Time is money and everyone is sue happy these days. You get a new crank im not liable for, or you straighten it yourself and put it back together.
 
I would plan on building a separate I beam based stand for bending work and build the fixture table for the fixture work. Big short beams go real cheap because not many people have a use for a single 10ft long 2ft deep I beam.
SLOWPOKE693 said:
How many bent housings do you plan on straightening??? Especially being a 12" X 16" table. :confused:
Click to expand...
They all bend when you do a ****ton of welding on them, especially the thin wall small tube jeep and classic vehicle stuff. He also deals in desert **** where idiots bend things all the time.

The D80 I just did was bent one way from a little from the factory. Now after all the **** I did to it it's bent less in a different way. If the shafts bolt up no problem I'm not even gonna measure it because I know that means it's good enough. His ******ed customers will look down the spindles and assume it's no good.
 
arse_sidewards said:
I would plan on building a separate I beam based stand for bending work and build the fixture table for the fixture work. Big short beams go real cheap because not many people have a use for a single 10ft long 2ft deep I beam.

They all bend when you do a ****ton of welding on them, especially the thin wall small tube jeep and classic vehicle stuff. He also deals in desert **** where idiots bend things all the time.

The D80 I just did was bent one way from a little from the factory. Now after all the **** I did to it it's bent less in a different way. If the shafts bolt up no problem I'm not even gonna measure it because I know that means it's good enough. His ******ed customers will look down the spindles and assume it's no good.
Click to expand...

Im talking about the table only being 12" x 16". Most cast centers are that wide before you even get into where the tubes are.
 
Bottle Jack and chain. I wouldn't bother with trying to mess with a tiny table like that.
 
SW does have a section properties analysis tool. Works just like the measure tool. Section the model through the plane indicated and select the cut face. Analysis ribbon -> section properties. Bottom values are principal moments of inertia of the area. Units are in^4 the bigger value is the one you need. Compare this value to the beam (124 in^4) to compare stiffness. By examining the weakest part of your structure actual will be a little better.

It's a dirty math method, but it gets you close.

section here **********er.png
 
UBERNERD said:
SW does have a section properties analysis tool. Works just like the measure tool. Section the model through the plane indicated and select the cut face. Analysis ribbon -> section properties. Bottom values are principal moments of inertia of the area. Units are in^4 the bigger value is the one you need. Compare this value to the beam (124 in^4) to compare stiffness. By examining the weakest part of your structure actual will be a little better.

It's a dirty math method, but it gets you close.
Click to expand...

that is the ticket, thank you

1752119836838.png


1752120028706.png
 
SLOWPOKE693 said:
How many bent housings do you plan on straightening??? Especially being a 12" X 16" table. :confused:
Click to expand...

SLOWPOKE693 said:
Im talking about the table only being 12" x 16". Most cast centers are that wide before you even get into where the tubes are.
Click to expand...

SLOWPOKE693 said:
He hasn't corrected anyone yet, so im assuming it is 12" x 16" until further clarification is made.
Click to expand...

at the moment the design is 16" wide x 12" tall x 72" long, now that i have some numbers to work with i may make some adjustments to the dimensions but unlikely

the axle adjustment with force is the secondary purpose, hopefully not many but its always nice to have a work surface that you can fixture off of

1752123748863.png


1752123969363.png


Chevy_man said:
Bottle Jack and chain. I wouldn't bother with trying to mess with a tiny table like that.
Click to expand...

this is how i dealt with the 8.8 on my bronco, i beam worked perfect but is useless for anything else.

1752120216983.png


current table is not sturdy enough for adjustment with ignorance and force.
1752123969052.png
 
mobil1syn said:
at the moment the design is 16" wide x 12" tall x 72" long, now that i have some numbers to work with i may make some adjustments to the dimensions but unlikely

the axle adjustment with force is the secondary purpose, hopefully not many but its always nice to have a work surface that you can fixture off of

1752123748863.png


1752123969363.png




this is how i dealt with the 8.8 on my bronco, i beam worked perfect but is useless for anything else.

1752120216983.png


current table is not sturdy enough for adjustment with ignorance and force.
1752123969052.png
Click to expand...

You didn't need the I beam. Just need to quit being dumb...

Chain on either end under the jack. Maybe a piece of c-channel under the jack if you want to be safe about it.
 
Chevy_man said:
Chain on either end under the jack. Maybe a piece of c-channel under the jack if you want to be safe about it.
Click to expand...
That'll fix your piece of **** bent 10b rear good enough to go down the road and will probably work in a pinch but isn't appropriate for regularly doing more precise work on bigger axles, which is what OP does.
 
Professional welder did a walk around his shop video the other day, pointed at his table and said by the time I get all the clutter off, I can genrally have the job finished working off the floor. Of course he is in his thirtys and still limber
 
The only other concern I think might be worth addressing is the stiffness of the top surface itself. Not the primary structure, just the surface deflecting/buckling under load when the pressure points aren't directly over your reinforcing ribs. I'd be tempted to add an internal spine lengthwise down the center, and maybe another 2 or 3 horizontal ribs just so you don't get ripples

Something I did on my table that could be interesting here, is make the center spine something heavy like 2x4 or 3x4.250 rectangle, then sink some receiver hitch tubes in at whatever intervals you find most handy. Then your axle stands can just pin in with hitch pins, and you can bottle jack directly off the surface anywhere you want along that spine. You can also put stuff like bench grinders and vices on hitch pedestals so they drop into the top of the table and don't walk away from you.

I don't seem to have a pic of the underside, but here's the top:

IMG_1437.JPG
 
arse_sidewards said:
That'll fix your piece of **** bent 10b rear good enough to go down the road and will probably work in a pinch but isn't appropriate for regularly doing more precise work on bigger axles, which is what OP does.
Click to expand...

Regularly? I thought this was the guy who built the death trap bronco out of an erector set because he couldn't weld?
 
Chevy_man said:
You didn't need the I beam. Just need to quit being dumb...

Chain on either end under the jack. Maybe a piece of c-channel under the jack if you want to be safe about it.
Click to expand...

yea, not interested in that

arse_sidewards said:
That'll fix your piece of **** bent 10b rear good enough to go down the road and will probably work in a pinch but isn't appropriate for regularly doing more precise work on bigger axles, which is what OP does.
Click to expand...

uh fabbin is a terrible way to make a living, im just a guy who builds fixtures to force himself to take his time and do better work.


AgitatedPancake said:
The only other concern I think might be worth addressing is the stiffness of the top surface itself. Not the primary structure, just the surface deflecting/buckling under load when the pressure points aren't directly over your reinforcing ribs. I'd be tempted to add an internal spine lengthwise down the center, and maybe another 2 or 3 horizontal ribs just so you don't get ripples
Click to expand...

already working on that, it just takes so much time to do the slot/tab stuff i wasnt going to do it until i knew that the idea would kina work.
 
I'm not sure why anyone would ever waste the time to fix a bent 8.hate :flipoff2:
 
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