From Veeduber@aol.com  Sat Sep 30 21:59:00 1995
msgnum: msg16777
Date: Sat, 30 Sep 1995 22:58:33 -0400
From: Veeduber_at_aol_dot_com
Subject: Grendel, Saturday

Grendel, Saturday.  Help Needed

Having decided to stay here in the drizzly northwest until Grendel has four
good wheels, I devoted most of the day to tracking down a new stub axle and
reduction gearbox.  And it didnžt rain.  The sun came out, the wind came up,
the clouds blew off toward Canada and I was treated to wondrous vistas of Mt.
Rainier and trees shrugging into their autumn dress, swirls of leaves chasing
one another across the country roads as I meandered from junky to junky in
search of the perfect stub axle.

Found one, I hope.  The boss wasnžt there but for $50 cash money the hired
man will give me the run of the yard tomorrow.  We shall see.

Back to the weldors and machine shops of the port, tracking down material to
make a real puller.  Found some Grade 8, 16 thread-per-inch threaded rod.
 Kinda rusty but it will clean up.  Found some Grade 5 long-nuts at another
shop, just about  to close for the day.  Bought two.  A welding shop had some
1/2ž flat stock, was eager to sell but I needed it cut and the guys with
greasy fingernails had already left for the day.  Anxiously asked to return
on Monday, which I will do.  There are some hungry people around the
waterfronts of Puget Sound. 

Here is what Ižm trying to make:  A steel pentagon fabricated from five
identical pieces of mild steel, 1/2ž thick by 3-3/4ž long on the short side,
each piece cut at a 35 degree angle on each end, the angles opposite to each
other so the piece comes out as a rhomboid instead of a slanted rectangle.
 The steel will be two or three inches wide, which ever the shop has. 

With a deeply chamfered hole to accept a lug bolt drilled in the
center/middle of each piece, and the five pieces welded together in a flat
ring, I will have a fixture that will bolt to a Volkswagen brake drum.
 Ideally, youžd flame-cut the plate from a hunk of armor plate.  Ižm winging
it, trying to  keep it within my budget and abilities.

Ižve specžd a 35 degree cut instead of the 36 degrees because I donžt expect
any of the cuts or drillings to be very accurate.  Ižll have to do the
drilling without benefit of a drill press and hogging out a hole big enough
for a VW wheel stud is going be a pretty sloppy job without holding the work
in a vise.  Ižll probably have to drill some small diameter holes in each
piece, secure them to a baulk of timber with deck screws to keep them from
moving around as I hog the holes in them with a hand-drill.

To assemble the pentagon as accurately as possible, Ižll bolt the pieces to a
brake drum, filing and cutting until I get a symmetrical fit.  My host has
arranged for me to use a small mig welder belonging to a friend.  When Ižm
satisfied with the fit Ižll haul the assembly to the friendžs house  then
tack-weld the corners of the pentagon pieces.

To make the puller-part of the puller Ižll ask the welding shop to cut me
five pieces of 1/2ž by 2ž bar stock, six inches long along the short side
with each end cut at  45 degree angles opposite to one another.  Again, that
isnžt the proper angle but youžve got to pay for each set-up of the saw,
after that each cut is only fifty cents.  Ižll grind, cut and file to get the
angles a little closer before I tack-weld the thing together.  This part of
the work will have to be done at the friendžs house, and Ižll probably have
to drill some small assembly holes and jig the thing together with bailing
wire to insure itžs properly aligned before welding.  Structures built in
space then to move around a lot from the welding heat.

The threaded nut will be positioned about 4-1/2ž above the upper surface of
the pentagon, held in place during assembly by a section of the threaded rod.
 The Grade 5 long-nut 1-1/2ž across the flats.  Ižll cut a 12ž piece of the
threaded rod for the screw of the puller, converting it into a bolt by
welding a nut to the end.  Normally, the puller-part would be the hub from a
real puller, something with an Acme thread and enough beef to pull the world
apart, but again, Ižm going with what I can find, with what I can afford.  

When Ižm satisfied with the fit and alignment, Ižll do the finish-welding,
building up a nice fillet at every joint to carry the loads smoothly around
the corners.  If I weld from side to side, and give the welds a chance to
cool before going on, I should end up with an accurately made Volkswagen
drum-puller.

To turn the screw Ižll buy a 1-1/4 socket and weld it to a five-foot piece of
1/2ž x 3ž bar stock.  To prevent the puller from turning as I turn the screw,
Ižll weld attachments to the pentagon plate to accept a bolted-on anti-torque
lever made from a section of angle iron or bar stock.  The lever will press
against the ground toward the rear of the vehicle while I play Tarzan on the
five-foot long welded-up socket wrench.

Ižve calculated that I should be able to generate about 8 tons of symmetrical
pulling force using only my body weight.   By reversing the welded-up
socket-wrench and raising it with the hydraulic jack, I can generate about 80
TONS of force.  Of course, Ižll never see 80 tons.  Even 8 tons tosses the
vehicle around.  But if I were at home I would chain the swing-plate and axle
to the concrete, allowing me to use the full potential of  a powerful puller
or welded-up socket wrench, which is my little trick for unscrewing difficult
wheel nuts and popping off sticky brake drums.  But Ižm a long way from home.

And I could use some help.

My only measuring tools are my 6ž machinistžs pocket scale and a six-foot
tape measure.  Ižve calculated the diameter of Grendelžs rear drums as 10.4ž,
both by direct measurement -- wiring a pair of hacksaw blades to opposite
sides of the drum and measuring between them above the hub -- and by
measuring the circumference of the drum with the tape measure and playing
with pi.  Starting with those dimensions I came up with a bolt-hole diameter
of 8.025ž, lug-bolt spacing of 4.75ž, hub height of 2-7/16ž, axle projection
of 1ž.   These dimensions are important not only for fabricating the puller
but for calculating the maximum loads in the parts.  A small error can have a
profound effect, given the leverage factors Ižm dealing with.  

Could someone please double check these dimensions for me?   Ižll probably
make some paper patterns to double-check myself but tunnel vision is a
marvelous thing, permitting a person to make same error over and over again.

If someone has a protractor and could lay-out the vertical straps, Ižd like
to know the angles.  x-axis: 4.0125 (or half the bolt-circle diameter),
y-axis: 4.4375ž.  Ižve guesstimated the hypotenuse as 6ž.   If therežs an
engineer in the house Ižd like to hear his opinion of lengthening the legs to
about 7 inches; the angle seems a little flat for the loads it will have to
handle.

-Bob