Subject: Angle Iron support bridge, need help before I fabricate.

From: [email-masked] (H.Shrikumar)
Date: 30 Jun 1996 02:49:17 GMT

Hi,

I need to fabricate a home-brew version of a Porsche Special Tool to
support the weight of an engine block. (Porsche wants $850 for what is
but a bar and an eye bolt and a hex-nut!). I could use some pointers to
on a couple of questions that should be a real easy cookie to you
frequent fabricators.

The jig is basically a cantilever that rests on the fenders/wheel-well
on the two ends on wood blocks, and hangs the engine-block by its
lifting hook in the middle.

        20in                    32in
  ----------------+------------------------------
  ####            O                          ####
  ####          350lb                        ####
  ####                                       ####
wood block,    eye-bolt in angle-iron bar, wood-block

1. Does 1/8" x 1.25" x 1.25" x 60" (L-section) galvanized angle iron
(from ACE) have a high enough buckling strength to hold the 350lb
engine block up safely?

2. How much would the beam flex under load? (I need to able to correct
for that by tightening the hex-nut on the eyebolt).

Thanx in advance for an answer, or any pointers to a formula, or a good
handbook that might have tables or formulae that I can apply quickly?

3. What is the best way to orient the L-section ?

I am guessing this would be the strongest, given that the load is going
to hang at about 10 degrees off the vertical slanting down towards the
left in this cross section (side) view (with 1/2in hole for the
eye-bolt):

               +-- | ---
               |
               |
               |

Or is my qualitative reasoning very much in need of sobering up ?

Thanx very much in advance !!

--//Shrikumar

'82 924 - "EA 425 Fahrvergnuegen"
[email-masked]

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From: [email-masked] (Dion Hollenbeck)
Date: Sun, 30 Jun 1996 15:11:31 GMT

>>>>> "H" == H Shrikumar <[email-masked]> writes:

H> I need to fabricate a home-brew version of a Porsche Special Tool to
H> support the weight of an engine block. (Porsche wants $850 for what is
H> but a bar and an eye bolt and a hex-nut!). 

H> 1. Does 1/8" x 1.25" x 1.25" x 60" (L-section) galvanized angle iron
H> (from ACE) have a high enough buckling strength to hold the 350lb
H> engine block up safely?

I suspect that you will do some welding on this??  If so, do NOT get
galvanized.  First, it is VERY hard to weld on, and second it emits
large quantities of very toxic smoke when heated to welding
temperatures.  Sorry I don't know anything about the strength.

dion

-- 
Dion Hollenbeck (619)597-7080x164                 Email: [email-masked]
Sr. Software Engineer - Vigra Div. of Visicom Labs  San Diego, California

---

From: Clarence Noyer <[email-masked]>
Date: 30 Jun 1996 22:39:29 GMT

I think that if you and a couple of buddies were to stand on the loading 
point ofsuch a bar, you would not feel safe.

Go see an engineering instructor at your institution for some design 
information.  There is good information in the Machinerys Handbook and in 
any steel manual but if you are starting from scratch, it easier to ask 
someone already there.

If you can see one of these crutches, you could get some idea of the 
parts sizes.

Good luck.

"CC"

---

From: [email-masked] (Tim Shoppa)
Date: 1 Jul 1996 00:28:15 GMT

In article <[email-masked]>,
>(from ACE) have a high enough buckling strength to hold the 350lb

Maybe, but I wouldn't count on it.  I just walked over to a 1/8" x 1.5"
x 1.5" x 72" CRS angle I have lying here, and found that if I support it at
the ends and press down at the center with 50 pounds or so of force
that it droops about 1/2".  If this piece didn't buckle under
the 350lb load, it would almost certainly be drooping considerably at
the center (probably with a twist, too.)  

I would *highly* recommend that
you find a section of I-beam for this application.  Take a look
at some engine hoists to get an idea of the size you'd need.  Even
better, think about renting an engine hoist for the few days you'll
need it.  If you look at typical engine hoists, they are *far* beefier
than the design you are proposing.

If you do decide to roll your own, don't risk your safety with ordinary
Grade 2 hardware.  Spend the few extra cents to get Grade 8.  If
the hardware isn't marked, it's Grade 2, and shouldn't be considered
at all for any dangerous loads.  (Just out of principle I no longer
use any Grade 2 hardware for anything!)

Tim. ([email-masked])

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From: [email-masked] (David R Brooks)
Date: Sun, 30 Jun 1996 23:07:11 GMT

>Or is my qualitative reasoning very much in need of sobering up ?

IMHO, an L-section, no matter how oriented, would be far too weak. Per
your drawing, even were the ends solidly clamped (not just resting on
the blocks), the bar will twist, and almost certainly buckle under the
load you mention. 
 Most applications of this sort would use an I-section beam, so that
the upper & lower webs are in compression & tension. I must leave it
to those more knowledgeable to determine the correct size (there are
indeed standard tables, but I don't have them).
 You won't need to weld it: just drill 2 holes in the lower web (1
each side of the central "fin"), and put in a U-bolt. Put the load
accurately under that central fin.

---

From: [email-masked] (Paul Amaranth)
Date: 1 Jul 1996 13:29:33 GMT

>than the design you are proposing.

I suspect this is not a replacement for an engine hoist, but a necessary
tool required to support the engine while doing something else.  I had
to fabricate something similar for my TR8 the other year when I rebuilt
the front suspension (the suspension is bolted to a subframe that also
supports the engine - If you take the subframe off, there's nothing
to hold up the engine thus requiring a tool such as described).  I used
a piece of 1x2 steel tubing with a 1/8 wall that I had lying around.
It was adequate, but the load was distributed at two points with chains
and not concentrated at a single point.  I don't think I would have used
it if I had a single point load to contend with.

Another point to consider is that you're not supporting the entire
engine weight, since the rear motor mount is still connected (at least
in my case, I don't know about your situation).

All in all, though, I wouldn't use 1/8 angle.  You can bend that stuff
with your bare hands.  I'd probably use a piece of 2x2x1/4 angle.  You'd
like something that you could stand on the end of a 6' piece cantalevered
>from  one end and not worry about it collapsing under you (to put it in
subjective terms).  Get it from your local steel dealer, rather than a
hardware store.  It will be cheaper (particularly if you can get a piece
>from  their cutoff pile) and you'll have a better idea of it's composition.

The other thing to worry about is the eyebolt.  Cheap hardware WILL
fail; the threads will pull right out under load.  This is not fun.
(this is also why a lot of lifting hardware you buy at the cheap hardware
stores has warnings about using it to lift people or loads - they want
to avoid the liability if you do something stupid).  350 lbs isn't that
much, but you should do the calculations to determine the correct size
and number of threads needed and then use good quality hardware of known
composition.   I think either grade 5 or 8 would work for this application
if it was sized correctly, but I'd stay away from the unmarked crap.

Now you know why they charge so much for a piece of steel with an eyebolt
in it.

Disclaimer:  I am not a structural engineer and my opinions are worth what
you payed for them.  Don't do anything without advice from a certified
profesional.  I am not liable for anything you do.  If I were to tell you
to do anything, it would be to take it to a Dealer and let them worry
about it.

--
Paul Amaranth  Manager User Services - office: (810) 370 4541 (also voicemail)
               (e-mail)     [email-masked]         
               URL http://www.acs.oakland.edu/~amaranth

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From: [email-masked] (H.Shrikumar)
Date: 2 Jul 1996 15:39:52 GMT

In article <[email-masked]>,
>>>(from ACE) have a high enough buckling strength to hold the 350lb

Thank you very much, all of you that found the time and is helping me
out ... I very much appreciate it !

>if it was sized correctly, but I'd stay away from the unmarked crap.

Ok, angle iron is out.  Taking up on a couple of suggestions, I am now
thinking in terms of getting steel square or rectangle section, or
maybe steel pipe, from the steel vendor, not the h/w store, making sure
it is of high grade. The Porsche tool also seems to use a square
section tube so it is the right direction. (sadly, it is not a in-stock
item, I cannot look see one unless I actually pre-pay and special order
it! Hence the return to design principles.)

>in my case, I don't know about your situation).

That is true ... exact same situation here. There is a way to do it
with an engine hoist, but that involves a more complicated procedure
than I can deal with practically.

One other complication is I anticipate the need for this tool to be in
installed position for a week, maybe more, and renting an engine hoist
for so long makes no economic sense.  I would rather spend $40 even
$100 fabricating something I can have for keeps, than spend $200 on
rental.

Thanx much everybody ... I will continue to check this group, for any
more suggestions you might have. Once I have a final design, I will
present it for your critique.

-- //Shrikumar 
   [email-masked]

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From: [email-masked] (Peter Brooks)
Date: 2 Jul 1996 22:58:35 GMT

Not terribly familiar with the strengths of material, but a conventional
engine hoist is made of 2" x 2" steel, with (I think) 1/4" walls.  I weigh
closer to 350 pounds than I'd like, and *I* wouldn't stand on the lifting
eye end of your rig.  OTOH, I'd think about 2 x 2 x 1/4" angle, perhaps with
some other angle welded on the side to form a Tee.  That would keep the
angle from buckling quite so readily.

Pete Brooks

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From: "John R. Johnson" <[email-masked]>
Date: Wed, 3 Jul 1996 13:54:09 -0500

Do not use angle iron for the beam.  To load it correctly you would have
to mount it in a V rather than an L.  That size angle is definately
inadequate.  Get a heavy piece of steel.  2 1/2 inche square tubing like
they use for trailer hitches would be fine.  Barring that, you may be
able to get a building support pole at the lumberyard that would carry
the weight.  Make sure you use at least grade 5 eyebolt.  I would prefer
grade 8.  Do NOT use regular hardware store hardware.  A 350 pound engine
could ruin your day if it dropped on your face!  

John

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From: Roger Gibbs <[email-masked]>
Date: Thu, 4 Jul 1996 00:27:33 GMT

>>Thanx in advance for an answer, or any pointers to a formula, or a  snip

I had a similiar situation with an Audi about two years ago.  Sounds
like basically the same lifting arraingement, except the lifting
point for the Audi was approximately centered. ( I needed to remove the 
oil pan and on this car this required removing the subframe, which 
required that the engine be supported).

I used to 2x4s on end.  I used wood spacers between the 2x4s and
screwed the assembly together.  I had a heavy eye bolt that I passed
in between the 2x4s. I do not know how much weight was supported.
The Audi 4 cylinder engine was partially supported by the trans-
mission.  Note:
    *I did not use the eye bolt to lift the engine. I  placed
a floor jack under the engine and lifted it with the jack.  I then
tightened the eye bolt to remove any slack, then lowered the floor
jack.
    * I rigged up a support under the engine to act as a
fail safe in case of eye bolt shear.  When I was anywhere near
being under the engine I had multiple additional supports.

I had originally planned to fabricate a support out of steel
tubing, but I rigged up the 2x4 support in about 15 minutes and
eyeballed the deformation (wasn't much) when I released the floor
jack. .... it worked for me.

-Roger

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From: [email-masked] (H.Shrikumar)
Date: 4 Jul 1996 07:08:53 GMT

In article <[email-masked]>,
>closer to 350 pounds than I'd like, and *I* wouldn't stand on the lifting

All you guys cautioned me about the difference between a steel supply
yard and the local hardware store. Well one thing led to another, and I
ended up looking up my friendly neighbourhood steel fabricator who is
willing to sell me good quality steel, grade 8 bolts, and drill the
holes for me as well. Not bad!

So finally this thing is going to be a steel box section beam.  The
exact section I will know on friday (depending on what cut piece is
lying around), but I will keep the above advice on wall thickness in
mind.

The cost, between $30-$45, which to say the least has one fewer digit
than the Porsche special tool :-) Cool!

Thanks again!

--//Shrikumar