Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical piece
of 150" long 2" x 2" x .250" square tube. There is a 48" right angle leg at
the top with a diagonal brace that comes in at 21" on the 48" horizontal and
150" vertical. I have used one pin at top and bottom, using a grade 8 1/2"
bolt that will fit into sockets top and bottom. The lifting point is
approximately 3" in from the end of the 48" top horizontal standoff.

Any predictions from the engineers in the group as to bending in the middle
of the 150" section with a 150# load? I really think that the maximum I
would lift with this is 21 gallons of water in the winter. Mostly, less
than 50# of groceries including the lift basket. Just a convenience device
to keep us from making several trips up and down the steep stairs schlepping
bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA standards,
and that will help a lot. Still, it will be nice to just pile groceries or
firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I get
the base footer poured, and make a 150# test lift, I will report the actual
lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a few
days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at least.

So much to do. So little time.

Steve

Steve B wrote:

Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical piece
of 150" long 2" x 2" x .250" square tube. There is a 48" right angle leg at
the top with a diagonal brace that comes in at 21" on the 48" horizontal and
150" vertical. I have used one pin at top and bottom, using a grade 8 1/2"
bolt that will fit into sockets top and bottom. The lifting point is
approximately 3" in from the end of the 48" top horizontal standoff.

Any predictions from the engineers in the group as to bending in the middle
of the 150" section with a 150# load? I really think that the maximum I
would lift with this is 21 gallons of water in the winter. Mostly, less
than 50# of groceries including the lift basket. Just a convenience device
to keep us from making several trips up and down the steep stairs schlepping
bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA standards,
and that will help a lot. Still, it will be nice to just pile groceries or
firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I get
the base footer poured, and make a 150# test lift, I will report the actual
lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a few
days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at least.

So much to do. So little time.

Careful, there, what you need to worry about (big time) is buckling on the main
vertical component. Might want to weld on a piece of flat bar on edge to stiffen
it or something. As is, it can suddenly fail and if you're under it you can get
hurt, almost got my leg broke one time when a similar thing buckled on me ..

GWE

"Grant Erwin" wrote in message
...
Steve B wrote:

Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical
piece of 150" long 2" x 2" x .250" square tube. There is a 48" right
angle leg at the top with a diagonal brace that comes in at 21" on the
48" horizontal and 150" vertical. I have used one pin at top and bottom,
using a grade 8 1/2" bolt that will fit into sockets top and bottom. The
lifting point is approximately 3" in from the end of the 48" top
horizontal standoff.

Any predictions from the engineers in the group as to bending in the
middle of the 150" section with a 150# load? I really think that the
maximum I would lift with this is 21 gallons of water in the winter.
Mostly, less than 50# of groceries including the lift basket. Just a
convenience device to keep us from making several trips up and down the
steep stairs schlepping bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA
standards, and that will help a lot. Still, it will be nice to just pile
groceries or firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I get
the base footer poured, and make a 150# test lift, I will report the
actual lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a
few days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at
least.

So much to do. So little time.

Careful, there, what you need to worry about (big time) is buckling on the
main vertical component. Might want to weld on a piece of flat bar on edge
to stiffen it or something. As is, it can suddenly fail and if you're
under it you can get hurt, almost got my leg broke one time when a similar
thing buckled on me ..

GWE

Thanks, Grant. I have been standing back and looking at this, and I EXPECT
bowing in the middle. How much, of course is going to depend on the load.
Since I don't anticipate loading it that much, I think I can live with the
bowing. HOWEVER, knowing myself, I will continue to increase the load.
Welding a flatbar strengthener along the edge is a great idea, it's just
that if I do it, I won't be able to measure the ACTUAL deflection. But
then, to accurately assess this, I would almost have to load until failure
occurs, then backtrack. I believe I will put a 1/4" x 2" FB stiffener for
about six feet, centered, and call it a day.

I don't want to do this again if it fails.

Steve

Steve B wrote:

"Grant Erwin" wrote in message
...

Steve B wrote:


Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical
piece of 150" long 2" x 2" x .250" square tube. There is a 48" right
angle leg at the top with a diagonal brace that comes in at 21" on the
48" horizontal and 150" vertical. I have used one pin at top and bottom,
using a grade 8 1/2" bolt that will fit into sockets top and bottom. The
lifting point is approximately 3" in from the end of the 48" top
horizontal standoff.

Any predictions from the engineers in the group as to bending in the
middle of the 150" section with a 150# load? I really think that the
maximum I would lift with this is 21 gallons of water in the winter.
Mostly, less than 50# of groceries including the lift basket. Just a
convenience device to keep us from making several trips up and down the
steep stairs schlepping bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA
standards, and that will help a lot. Still, it will be nice to just pile
groceries or firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I get
the base footer poured, and make a 150# test lift, I will report the
actual lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a
few days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at
least.

So much to do. So little time.

Careful, there, what you need to worry about (big time) is buckling on the
main vertical component. Might want to weld on a piece of flat bar on edge
to stiffen it or something. As is, it can suddenly fail and if you're
under it you can get hurt, almost got my leg broke one time when a similar
thing buckled on me ..

GWE


Thanks, Grant. I have been standing back and looking at this, and I EXPECT
bowing in the middle. How much, of course is going to depend on the load.
Since I don't anticipate loading it that much, I think I can live with the
bowing. HOWEVER, knowing myself, I will continue to increase the load.
Welding a flatbar strengthener along the edge is a great idea, it's just
that if I do it, I won't be able to measure the ACTUAL deflection. But
then, to accurately assess this, I would almost have to load until failure
occurs, then backtrack. I believe I will put a 1/4" x 2" FB stiffener for
about six feet, centered, and call it a day.

I don't want to do this again if it fails.

Steve



This is on the vertical member, mind you, NOT the horizontal one.

Machinery's Handbook has tables of max loading on columns. Worth checking, the
library has one if you don't, don't need the latest.

GWE

"Grant Erwin" wrote in message
...
Steve B wrote:

"Grant Erwin" wrote in message
...

Steve B wrote:


Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical
piece of 150" long 2" x 2" x .250" square tube. There is a 48" right
angle leg at the top with a diagonal brace that comes in at 21" on the
48" horizontal and 150" vertical. I have used one pin at top and
bottom, using a grade 8 1/2" bolt that will fit into sockets top and
bottom. The lifting point is approximately 3" in from the end of the
48" top horizontal standoff.

Any predictions from the engineers in the group as to bending in the
middle of the 150" section with a 150# load? I really think that the
maximum I would lift with this is 21 gallons of water in the winter.
Mostly, less than 50# of groceries including the lift basket. Just a
convenience device to keep us from making several trips up and down the
steep stairs schlepping bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA
standards, and that will help a lot. Still, it will be nice to just
pile groceries or firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I
get the base footer poured, and make a 150# test lift, I will report the
actual lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a
few days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at
least.

So much to do. So little time.

Careful, there, what you need to worry about (big time) is buckling on
the main vertical component. Might want to weld on a piece of flat bar on
edge to stiffen it or something. As is, it can suddenly fail and if
you're under it you can get hurt, almost got my leg broke one time when a
similar thing buckled on me ..

GWE


Thanks, Grant. I have been standing back and looking at this, and I
EXPECT bowing in the middle. How much, of course is going to depend on
the load. Since I don't anticipate loading it that much, I think I can
live with the bowing. HOWEVER, knowing myself, I will continue to
increase the load. Welding a flatbar strengthener along the edge is a
great idea, it's just that if I do it, I won't be able to measure the
ACTUAL deflection. But then, to accurately assess this, I would almost
have to load until failure occurs, then backtrack. I believe I will put
a 1/4" x 2" FB stiffener for about six feet, centered, and call it a day.

I don't want to do this again if it fails.

Steve

This is on the vertical member, mind you, NOT the horizontal one.

Machinery's Handbook has tables of max loading on columns. Worth checking,
the library has one if you don't, don't need the latest.

GWE

Yep, that would be on the vertical. The horizontal is much shorter, and has
a diagonal brace under it at 21" out. I have a 'Thomas Glover Pocket Ref,
and will see if I can find out anything. BUT, it would be different, as it
connects into the vertical, and the vertical bow is the critical part.

Again, as I say, I doubt the thing will ever have 100# on it, but I just
like being triple sure when something can come down and do brain damage.

Steve

Your water will be 168 lbs plus container weight.

You might want consider adding a section of 1 X 2 channel to the vertical
column (web side out), opposite side of the horizontal boom.

--
J Miller
"Steve B" wrote in message
news:REa7g.8445$QP4.3043@fed1read12...
Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical piece
of 150" long 2" x 2" x .250" square tube. There is a 48" right angle leg
at the top with a diagonal brace that comes in at 21" on the 48"
horizontal and 150" vertical. I have used one pin at top and bottom,
using a grade 8 1/2" bolt that will fit into sockets top and bottom. The
lifting point is approximately 3" in from the end of the 48" top
horizontal standoff.

Any predictions from the engineers in the group as to bending in the
middle of the 150" section with a 150# load? I really think that the
maximum I would lift with this is 21 gallons of water in the winter.
Mostly, less than 50# of groceries including the lift basket. Just a
convenience device to keep us from making several trips up and down the
steep stairs schlepping bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA standards,
and that will help a lot. Still, it will be nice to just pile groceries
or firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I get
the base footer poured, and make a 150# test lift, I will report the
actual lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a few
days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at
least.

So much to do. So little time.

Steve

On Sun, 07 May 2006 13:21:16 GMT, "John Miller"
wrote:

Your water will be 168 lbs plus container weight.

You might want consider adding a section of 1 X 2 channel to the vertical
column (web side out), opposite side of the horizontal boom.

Or a jackstay with turnbuckle. If it flexes more than you like.

Pete Keillor

Steve B wrote:

Again, as I say, I doubt the thing will ever have 100# on it, but I just
like being triple sure when something can come down and do brain damage.

Steve


Steve
You did not say what kind of lifting device you plan to use. If you
plan to use a rope and one pulley at the top to lift 21 gallons of
water, it will need to be good for over 350 lb. If you have water at 168
lb. on one side of the rope, you will need to put more than 168lb.+ 10%
for pulley loss on the other side of the rope to get it to move. So you
will have more than 352.8 lb. on everything from the pulley up. For 50#
of groceries it will be 105 lb.
Don

"Pete Keillor" wrote in message
...
On Sun, 07 May 2006 13:21:16 GMT, "John Miller"
wrote:

Your water will be 168 lbs plus container weight.

You might want consider adding a section of 1 X 2 channel to the vertical
column (web side out), opposite side of the horizontal boom.

Or a jackstay with turnbuckle. If it flexes more than you like.

Pete Keillor

The whole thing will be rotating on pins to swing it in to the balcony. GWE
made the suggestion of a flatbar stiffener, which I think I will do.

Steve

"Don Murray" wrote in message
news


Steve B wrote:

Again, as I say, I doubt the thing will ever have 100# on it, but I just
like being triple sure when something can come down and do brain damage.

Steve
Steve
You did not say what kind of lifting device you plan to use. If you plan
to use a rope and one pulley at the top to lift 21 gallons of water, it
will need to be good for over 350 lb. If you have water at 168 lb. on one
side of the rope, you will need to put more than 168lb.+ 10% for pulley
loss on the other side of the rope to get it to move. So you will have
more than 352.8 lb. on everything from the pulley up. For 50# of groceries
it will be 105 lb.
Don


Sorry I forgot that important fact. I will be using a generic HF 450#
capacity electric hoist that can be used with a straight line, or with the
line reeved through a traveling hook, and deadmanned back to the hoist body.

Steve

On Sat, 6 May 2006 16:52:18 -0700, "Steve B"
wrote:

Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical piece
of 150" long 2" x 2" x .250" square tube. There is a 48" right angle leg at
the top with a diagonal brace that comes in at 21" on the 48" horizontal and
150" vertical. I have used one pin at top and bottom, using a grade 8 1/2"
bolt that will fit into sockets top and bottom. The lifting point is
approximately 3" in from the end of the 48" top horizontal standoff.

Any predictions from the engineers in the group as to bending in the middle
of the 150" section with a 150# load? I really think that the maximum I
would lift with this is 21 gallons of water in the winter. Mostly, less
than 50# of groceries including the lift basket. Just a convenience device
to keep us from making several trips up and down the steep stairs schlepping
bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA standards,
and that will help a lot. Still, it will be nice to just pile groceries or
firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I get
the base footer poured, and make a 150# test lift, I will report the actual
lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a few
days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at least.

So much to do. So little time.

Steve


With 150 lb at 3 feet from CL, your moment is 450 in-lbf. That's
equivalent to a 3 lb load on a cantilevered 150 inch beam, neglecting
the weight of the beam itself -- which doesn't apply here with a
vertical column. Too lazy to get out Machinery's Handbook, but that
doesn't seem like a lot. Note that if the beam does deflect much
then the moment increases so it's an unstable situation.

"Don Foreman" wrote in message
...
On Sat, 6 May 2006 16:52:18 -0700, "Steve B"
wrote:

Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical piece
of 150" long 2" x 2" x .250" square tube. There is a 48" right angle leg
at
the top with a diagonal brace that comes in at 21" on the 48" horizontal
and
150" vertical. I have used one pin at top and bottom, using a grade 8
1/2"
bolt that will fit into sockets top and bottom. The lifting point is
approximately 3" in from the end of the 48" top horizontal standoff.

Any predictions from the engineers in the group as to bending in the
middle
of the 150" section with a 150# load? I really think that the maximum I
would lift with this is 21 gallons of water in the winter. Mostly, less
than 50# of groceries including the lift basket. Just a convenience
device
to keep us from making several trips up and down the steep stairs
schlepping
bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA standards,
and that will help a lot. Still, it will be nice to just pile groceries
or
firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I get
the base footer poured, and make a 150# test lift, I will report the
actual
lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a few
days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at
least.

So much to do. So little time.

Steve


With 150 lb at 3 feet from CL, your moment is 450 in-lbf. That's
equivalent to a 3 lb load on a cantilevered 150 inch beam, neglecting
the weight of the beam itself -- which doesn't apply here with a
vertical column. Too lazy to get out Machinery's Handbook, but that
doesn't seem like a lot. Note that if the beam does deflect much
then the moment increases so it's an unstable situation.

Could you translate that to a clueless newbie version?

My greatest concern is the top mounting plate. I made a saddle for a 3 ply
2x6 beam that is 18" long. The insertion hole for the pin will be 2" out
from the end of the beam, giving the saddle 16" of contact with the beam.
There will be nine 1/4" x 2" lag bolts. The beam it is attached to is only
supported by an 8x8 post, and that post sits directly onto the top deck, not
running through to the ground or anything solid.

The bottom pin will go into a receiver that I made out of 2x2 square tube,
and welded 8 pieces of rebar onto to go into the concrete form I will make
around the base. I think the base will be substantial, and far steadier
than the top. The base should have no tendency to kick out, as it will go
down subgrade. The top is the weak point.

Again, as I said, this is a convenience grocery hoist, and probably will
lift no more than 50# at a time. Mostly in the 25# range.

But it sure is going to be spooky using it the first time with a test load.

Steve

On Sun, 07 May 2006 12:01:53 -0500, Don Foreman
wrote:

On Sat, 6 May 2006 16:52:18 -0700, "Steve B"
wrote:

Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical piece
of 150" long 2" x 2" x .250" square tube. There is a 48" right angle leg at
the top with a diagonal brace that comes in at 21" on the 48" horizontal and
150" vertical. I have used one pin at top and bottom, using a grade 8 1/2"
bolt that will fit into sockets top and bottom. The lifting point is
approximately 3" in from the end of the 48" top horizontal standoff.

Any predictions from the engineers in the group as to bending in the middle
of the 150" section with a 150# load? I really think that the maximum I
would lift with this is 21 gallons of water in the winter. Mostly, less
than 50# of groceries including the lift basket. Just a convenience device
to keep us from making several trips up and down the steep stairs schlepping
bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA standards,
and that will help a lot. Still, it will be nice to just pile groceries or
firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I get
the base footer poured, and make a 150# test lift, I will report the actual
lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a few
days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at least.

So much to do. So little time.

Steve


With 150 lb at 3 feet from CL, your moment is 450 in-lbf. That's
equivalent to a 3 lb load on a cantilevered 150 inch beam, neglecting
the weight of the beam itself -- which doesn't apply here with a
vertical column. Too lazy to get out Machinery's Handbook, but that
doesn't seem like a lot. Note that if the beam does deflect much
then the moment increases so it's an unstable situation.

Oops, brainfart, feet vs inches. Moment is 450 ft-lbf or 5400
in-lbf. Still doesn't seem too bad.

I'd place a tension member opposite the load, as perhaps a strip of 2"
x 3/16" band from top to bottom with maybe a 3" or 4" bridge in the
middle. Take a look at how engine hoists are built, e.g. the
horizontal beam in Harbor Freight item number 35915
www.harborfreight.com

This won't reduce the moment, but it will concentrate it to a small
region near the base. I'll do the moments of inertia trick later
(after dark) but my sense is that 2 x 2 x 1/4 square tube should be
able to handle this with max stress of well under 15 KSI in the
steel. The tension band(s) won't change this unless it (they) have
some spread at the base, but it will markedly reduce deflection in the
length of the column. That's good because deflection will increase
moment in your situation.

An even better solution would be to have a plate embedded in the
footing to which the tension band(s) could attach. My biggest
concern would then be with the footing itself. It had better go down
a fair ways so it won't tip.

On Sun, 07 May 2006 09:32:11 -0400, Pete Keillor
wrote:

On Sun, 07 May 2006 13:21:16 GMT, "John Miller"
wrote:

Your water will be 168 lbs plus container weight.

You might want consider adding a section of 1 X 2 channel to the vertical
column (web side out), opposite side of the horizontal boom.

Or a jackstay with turnbuckle. If it flexes more than you like.

Pete Keillor

Or two..and spreaders

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist

Steve,

Don't centre the bar on the 150" post. Start the reinforcing bar on
the base plate and run it half way up the post. Weld securely to the
base plate also.

Personally I'd use two bars and weld them to the back corners, at 45
degrees to the back side of the column.

From a column stability perspective 150" un-reinforced is too long.
Maximum unsupported length is 8.33 ft as per my CISC handbook.

Wolfgang

wrote in message
ups.com...
Steve,

Don't centre the bar on the 150" post. Start the reinforcing bar on
the base plate and run it half way up the post. Weld securely to the
base plate also.

Personally I'd use two bars and weld them to the back corners, at 45
degrees to the back side of the column.

From a column stability perspective 150" un-reinforced is too long.
Maximum unsupported length is 8.33 ft as per my CISC handbook.

Wolfgang


No, there is a pivot pin at top and bottom ends of the vertical so I can
pick up a load, lift it up, and swing it in and land it on the upper porch.
Same thing about taking things down off the porch. Pick it up, swing it
out, let it down. If this were rigid, bracing and bowing would be a simple
thing to fix.

Steve

On Sun, 7 May 2006 10:22:31 -0700, "Steve B"
wrote:


"Don Foreman" wrote in message
.. .
On Sat, 6 May 2006 16:52:18 -0700, "Steve B"
wrote:

Well, in the midst of all my other projects, I went out and in one day
completed my hoist davit project for my cabin. This uses a vertical piece
of 150" long 2" x 2" x .250" square tube. There is a 48" right angle leg
at
the top with a diagonal brace that comes in at 21" on the 48" horizontal
and
150" vertical. I have used one pin at top and bottom, using a grade 8
1/2"
bolt that will fit into sockets top and bottom. The lifting point is
approximately 3" in from the end of the 48" top horizontal standoff.

Any predictions from the engineers in the group as to bending in the
middle
of the 150" section with a 150# load? I really think that the maximum I
would lift with this is 21 gallons of water in the winter. Mostly, less
than 50# of groceries including the lift basket. Just a convenience
device
to keep us from making several trips up and down the steep stairs
schlepping
bags of groceries or "stuff".

A three phase ramp is being made as we speak, conforming to ADA standards,
and that will help a lot. Still, it will be nice to just pile groceries
or
firewood in the lift, and lift 'er up.

I personally don't think it will flex enough to be a problem. When I get
the base footer poured, and make a 150# test lift, I will report the
actual
lateral horizontal bending factor.

Anyone care to guess? Winner gets bragging rights. Place yer bets,
gentlemen. Will take a month or so. Going back up on the 19th, and a few
days to form and pour and cure the footer. This has been an ongoing
project, and it will take a while to complete. But, it's moving, at
least.

So much to do. So little time.

Steve


With 150 lb at 3 feet from CL, your moment is 450 in-lbf. That's
equivalent to a 3 lb load on a cantilevered 150 inch beam, neglecting
the weight of the beam itself -- which doesn't apply here with a
vertical column. Too lazy to get out Machinery's Handbook, but that
doesn't seem like a lot. Note that if the beam does deflect much
then the moment increases so it's an unstable situation.

Could you translate that to a clueless newbie version?

My greatest concern is the top mounting plate. I made a saddle for a 3 ply
2x6 beam that is 18" long. The insertion hole for the pin will be 2" out
from the end of the beam, giving the saddle 16" of contact with the beam.
There will be nine 1/4" x 2" lag bolts. The beam it is attached to is only
supported by an 8x8 post, and that post sits directly onto the top deck, not
running through to the ground or anything solid.

The bottom pin will go into a receiver that I made out of 2x2 square tube,
and welded 8 pieces of rebar onto to go into the concrete form I will make
around the base. I think the base will be substantial, and far steadier
than the top. The base should have no tendency to kick out, as it will go
down subgrade. The top is the weak point.

Again, as I said, this is a convenience grocery hoist, and probably will
lift no more than 50# at a time. Mostly in the 25# range.

But it sure is going to be spooky using it the first time with a test load.

Steve

I am now thoroughly confused. I envisioned a 150" high upside-down L,
like a gallows. The stuff about pins at top and bottom, saddle,
concrete base and 8x8 post has me baffled.

Steve,

Do you mean that your 2" x 2" post is restrained, from bending, also at
the TOP??? Ie. the post has a swivel (slewing bearing) at the top AND
bottom to permit slewing of the jib?

In which case you should have nothing to worry about.

Just to make sure we understand you correctly, can you post a sketch in
the appropriate place?

Wolfgang

"Don Foreman" wrote

I am now thoroughly confused. I envisioned a 150" high upside-down L,
like a gallows. The stuff about pins at top and bottom, saddle,
concrete base and 8x8 post has me baffled.


Follow me:

Three pieces:
one 150" long
one 48" long
one 21" long, each end cut on the diagonal

Assembled as you say, a gallows

Two pins welded along the center axis top and bottom of the 150" piece

The "gallows" sill sit into a receiver hole in a metal receiver that is
encased in in a concrete base.

The top pin will go into a short extension that comes off a beam end that
sticks out past the 8x8 vertical roof support at the corner of the deck.

Because it is at the corner of the top deck, it can rotate about 270
degrees.

A hoist is placed at the end of the gallows arm.

When I get it up, I shall post it to the mailbox.

I'm just mounting a swinging gallows arm on two pins.

Steve

wrote in message
ups.com...
Steve,

Do you mean that your 2" x 2" post is restrained, from bending, also at
the TOP??? Ie. the post has a swivel (slewing bearing) at the top AND
bottom to permit slewing of the jib?

In which case you should have nothing to worry about.

Just to make sure we understand you correctly, can you post a sketch in
the appropriate place?

Wolfgang


You pretty much got it. On the corner of my deck, there is an 8x8 support
post. It runs from the deck up to the beam that supports the rafter ends.
BUT, it runs about 18" past the vertical support column.

So, the only thing that is keeping the top beam stable is really the
rafters.

When I finish, I will post photos to the mailbox, or if you like, e mail me
at , and I can send you a picture.

Steve

On Sun, 7 May 2006 22:13:35 -0700, "Steve B"
wrote:


"Don Foreman" wrote

I am now thoroughly confused. I envisioned a 150" high upside-down L,
like a gallows. The stuff about pins at top and bottom, saddle,
concrete base and 8x8 post has me baffled.


Follow me:

Three pieces:
one 150" long
one 48" long
one 21" long, each end cut on the diagonal

Assembled as you say, a gallows

Two pins welded along the center axis top and bottom of the 150" piece

The "gallows" sill sit into a receiver hole in a metal receiver that is
encased in in a concrete base.

The top pin will go into a short extension that comes off a beam end that
sticks out past the 8x8 vertical roof support at the corner of the deck.

Got it, thanks! The column is restrained from lateral movement by
vertical pins at top and bottom.

Cranking the formulae from Machinery's Handbook thru MathCAD, using a
150 lb load hanging from a 3 foot horizontal beam at the top, it
looks like the peak bending stress in the column is about 2000 PSI --
minimal for steel. Peak lateral deflection in the column looks
like about 0.294 inches at a distance of about 92" down from the top.
This isn't completely accurate, is a bit pessimistic, because I
treated the load moment as a single lateral 900-lb load 6" down
from the top pin to produce the moment. If I got me sums right,
looks like you should be in good shape. I figure a 1/2" dia top pin
will see shear stress of about 4000 PSI, again very modest for steel.

Because it is at the corner of the top deck, it can rotate about 270
degrees.

A hoist is placed at the end of the gallows arm.

When I get it up, I shall post it to the mailbox.

I'm just mounting a swinging gallows arm on two pins.

Steve

"Don Foreman" wrote

If I got me sums right,
looks like you should be in good shape. I figure a 1/2" dia top pin
will see shear stress of about 4000 PSI, again very modest for steel.

Well, just looking at it, and having hands on experience with lots of
"stuff", I think it will be fine, too.

I put a picture of the cabin corner in the mailbox with the name davithoist.
I am going to go out and take another of the actual contraption and post
that, too. If you CAN go to the mailbox and view this picture, you will see
that there is a 34' composite beam, but it only rests on 8x8 posts that are
mounted directly to the deck and rafters.

This will be the weak point, pulling laterally on that beam. But, if I keep
the load low, there should not be enough lateral stress to even approach
critical mass. I have thought of putting in a stabilizer bar, but thought
I'd wait to see how it worked first.

Steve

Pictures are in dropbox under davithoist. Four pics or so. Didn't know it
was so easy to post pics. Will be doing it on future stuff to make it
simpler.

On the pic showing the saddle and davit, the pin is in the saddle, you just
can't see it.

On the cabin pic, the saddle will connect to the left side of the rafter end
beam/porch support beam, and 2" will stick out to the left so the hole will
be clear.

The base will be poured into a form plumb down from the top pin. The chalk
like on the base piece is going to be the top of the concrete.

PS to Don: The top horizontal of the "gallows" is 48", not 36".

Steve

"Steve B" wrote

The chalk
like on the base piece is going to be the top of the concrete.

Durn spellchecker. Supposed to be "chalk LINE".

Steve B wrote:
Pictures are in dropbox under davithoist. Four pics or so. Didn't know it
was so easy to post pics. Will be doing it on future stuff to make it
simpler.

Don't forget to type up a ".txt" file to go with it, notepad would work
fine.
Put "hard" carriage returns at the end of every line for best
readability. This
is so it won't get flagged as a possible virus and deleted...
--Glenn Lyford

Uhhhhh, guys,

How does one access the dropbox? Usta know, posted there myself..But,
time catches up.

Thanks,

Wolfgang

wrote in message
ups.com...
Uhhhhh, guys,

How does one access the dropbox? Usta know, posted there myself..But,
time catches up.

Thanks,

Wolfgang


http://www.metalworking.com/dropbox/

Steve,

Thanks for the link. Had a look.

I think your design is OK. The horizontal force at the top of the post
is quite small, about 1/3 of the vertical load.

My only concern is that you welded to a structural bolt (SAE Grade 5 or
8 slewing pin bottom, and top?). For lifting / hoisting stuff this is a
no-no since welding screws up the heat treatment. Too rapid cooling
would make the bolt steel brittle, and the bolt head could snap off at
embarrassing or dangerous times! I'd re-think that detail. Other than
that it looks ok.

Wolfgang

wrote in message
oups.com...
Steve,

Thanks for the link. Had a look.

I think your design is OK. The horizontal force at the top of the post
is quite small, about 1/3 of the vertical load.

My only concern is that you welded to a structural bolt (SAE Grade 5 or
8 slewing pin bottom, and top?). For lifting / hoisting stuff this is a
no-no since welding screws up the heat treatment. Too rapid cooling
would make the bolt steel brittle, and the bolt head could snap off at
embarrassing or dangerous times! I'd re-think that detail. Other than
that it looks ok.

Wolfgang


I had thought about that, and intend to make the fit as tight as possible
between the two receiver holes. I was going to stack a couple of washers,
and put some grease on them.

This unit will see very light use. It will travel about 180 degrees each
time, and be used about 50 times a year. I was not thrilled about the
bolts, but I wanted to keep the pivot point on center. I figure that I will
keep an eye on it, watch for wear, and if I have to, beef it up.

BTW, I will do the first test load with 150#, and measure the side
deflection at 75" up from bottom. I think it is going to be Gawd awful
strong for lifting 50# at a time.

It's just that the first test load will be about June.

Steve

In article eA28g.8578$QP4.224@fed1read12,
"Steve B" wrote:
This unit will see very light use. It will travel about 180 degrees each
time, and be used about 50 times a year. I was not thrilled about the
bolts, but I wanted to keep the pivot point on center. I figure that I will
keep an eye on it, watch for wear, and if I have to, beef it up.

BTW, I will do the first test load with 150#, and measure the side
deflection at 75" up from bottom. I think it is going to be Gawd awful
strong for lifting 50# at a time.

The tricky thing about brittle failure is that it could quite easily
take the 150 lb test load, work fine on the 50 lb loads for a while, and
then snap at 25 lbs one day, with essentially no warning. While the 50
lbs might not do any significant damage, what's the hoist pole going to
hurt when it lands, if it breaks free?

--
Cats, coffee, chocolate...vices to live by

"Ecnerwal" wrote in message
...
In article eA28g.8578$QP4.224@fed1read12,
"Steve B" wrote:
This unit will see very light use. It will travel about 180 degrees each
time, and be used about 50 times a year. I was not thrilled about the
bolts, but I wanted to keep the pivot point on center. I figure that I
will
keep an eye on it, watch for wear, and if I have to, beef it up.

BTW, I will do the first test load with 150#, and measure the side
deflection at 75" up from bottom. I think it is going to be Gawd awful
strong for lifting 50# at a time.

The tricky thing about brittle failure is that it could quite easily
take the 150 lb test load, work fine on the 50 lb loads for a while, and
then snap at 25 lbs one day, with essentially no warning. While the 50
lbs might not do any significant damage, what's the hoist pole going to
hurt when it lands, if it breaks free?


Nothing important. People. Propane tanks. Dogs. Cars.

I see your point.

Steve