Is there a standard way to splice gantry hoist track made from two
channel sections? I'd like to make a 16' track from four 8' lengths of
C4 x 5.4 channel. The constraints are that the trolley wheels have to
roll inside the lower flange, which rules out this pattern:
https://www.researchgate.net/profile...101002@1470947
and a vertical plate or tee section extending below the lower flanges
can't block the HF 1 ton trolley. I've already turned its wheels down
to fit in 3" channel.

The immediate application has the splice plate suspended from a roof
beam and the outer ends supported by tripods, allowing 8' of clearance
for my bandsaw mill on one side and maneuvering room in the 4' wide
storage shed on the other, plus enough outside overhang to load the
cut timbers onto a narrow trailer.

The maximum load in this case will be under 500 lbs but I've been
struggling to use this problem as an exercise in designing a splice
that allows the full load capacity of the channels or 1 ton trolley on
a 16' span without interfering with the rolling trolley. I might be
able to shim up the lower fillets of a piece of scrap W6 x 9 beam so
the channel fits against the web and flanges. It looks like I have to
accept tapping the lower flanges of the channel and trimming the cap
screws flush inside.

-jsw

"Jim Wilkins" wrote in message news
Is there a standard way to splice gantry hoist track made from two
channel sections? I'd like to make a 16' track from four 8' lengths of
C4 x 5.4 channel. The constraints are that the trolley wheels have to
roll inside the lower flange, which rules out this pattern:
https://www.researchgate.net/profile...101002@1470947
and a vertical plate or tee section extending below the lower flanges
can't block the HF 1 ton trolley. I've already turned its wheels down
to fit in 3" channel.

The immediate application has the splice plate suspended from a roof
beam and the outer ends supported by tripods, allowing 8' of clearance
for my bandsaw mill on one side and maneuvering room in the 4' wide
storage shed on the other, plus enough outside overhang to load the
cut timbers onto a narrow trailer.

The maximum load in this case will be under 500 lbs but I've been
struggling to use this problem as an exercise in designing a splice
that allows the full load capacity of the channels or 1 ton trolley on
a 16' span without interfering with the rolling trolley. I might be
able to shim up the lower fillets of a piece of scrap W6 x 9 beam so
the channel fits against the web and flanges. It looks like I have to
accept tapping the lower flanges of the channel and trimming the cap
screws flush inside.

-jsw
=============================================

I have no idea what "standard practice" is for this, but I'll toss out some
thoughts. First, cut one of the 8' channels in half and make three splices,
where each splice is in the middle of an uninterrupted span of the backing
channel by tapping one channel and using flat head bolts. That keeps the
central web thickness constant and lets one channel serve as the splice
plate for the other side. That would probably handle your current load but
maybe not the full 1 ton (I get a maximum stress of 3100 psi with a 250 lb
load in the center of a single 8' span, so you have plenty of safety margin
for your 500 lb load). Second, if you cannot use a tie plate below the
joint because of interference with the trolley but have room above, add a
short section of channel on top of the splice instead of a flat tie plate,
with bolts through the webbing. Doing both should get you a full strength
joint. You may only need to do this above the central splice, not all
three. Of course, how big and how many bolts and how long the upper channel
should be is left as an exercise for the reader :-).

--
Regards,
Carl Ijames

"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news
Is there a standard way to splice gantry hoist track made from two
channel sections? I'd like to make a 16' track from four 8' lengths
of
C4 x 5.4 channel. The constraints are that the trolley wheels have
to
roll inside the lower flange, which rules out this pattern:
https://www.researchgate.net/profile...101002@1470947
and a vertical plate or tee section extending below the lower
flanges
can't block the HF 1 ton trolley. I've already turned its wheels
down
to fit in 3" channel.

The immediate application has the splice plate suspended from a roof
beam and the outer ends supported by tripods, allowing 8' of
clearance
for my bandsaw mill on one side and maneuvering room in the 4' wide
storage shed on the other, plus enough outside overhang to load the
cut timbers onto a narrow trailer.

The maximum load in this case will be under 500 lbs but I've been
struggling to use this problem as an exercise in designing a splice
that allows the full load capacity of the channels or 1 ton trolley
on
a 16' span without interfering with the rolling trolley. I might be
able to shim up the lower fillets of a piece of scrap W6 x 9 beam so
the channel fits against the web and flanges. It looks like I have
to
accept tapping the lower flanges of the channel and trimming the cap
screws flush inside.

-jsw
=============================================

I have no idea what "standard practice" is for this, but I'll toss
out some thoughts. First, cut one of the 8' channels in half and
make three splices, where each splice is in the middle of an
uninterrupted span of the backing channel by tapping one channel and
using flat head bolts. That keeps the central web thickness
constant and lets one channel serve as the splice plate for the
other side. That would probably handle your current load but maybe
not the full 1 ton (I get a maximum stress of 3100 psi with a 250 lb
load in the center of a single 8' span, so you have plenty of safety
margin for your 500 lb load). Second, if you cannot use a tie plate
below the joint because of interference with the trolley but have
room above, add a short section of channel on top of the splice
instead of a flat tie plate, with bolts through the webbing. Doing
both should get you a full strength joint. You may only need to do
this above the central splice, not all three. Of course, how big
and how many bolts and how long the upper channel should be is left
as an exercise for the reader :-).

--
Regards,
Carl Ijames

My notes from a while ago give ~25 KSI and a sag of 1 in 145 for one
16' length of 4x5.4 channel with a 1000 Lb center load. It likely came
from an on-line calculator. I could buy a single 20' beam for the
track but I couldn't handle it by myself; the four separate pieces are
reasonable to lift on a stepladder since this is a temporary outdoor
installation when I use the sawmill.

I did a quickie setup with 8' of channel extending out 4' from the
shed to cut one 750# log into two lighter pieces and realized that the
16' track I hadn't completed could be suspended from the shed roof
beam at its center splice, which makes everything simple. With the
shorter track I had to set up an end support to bring the log out,
remove the support to cut, replace it to flip the log and remove it
again to size the second piece, as the log had been roughly squared
oversize before drying. An 8' track over the saw would let it pass the
end support, the other 8' gives 4' to pick up the logs in the shed
plus 4' out the other side to put the finished beams on a trailer.

The center-supported track is easy (except for erecting it) but I want
to consider how to splice a single span so I don't do anything
regrettable when drilling for the center-supported splice plate. I
think I'll drill the web and leave the flanges alone.

For the single span I can have a tie plate below but not above the
lower flange, so the cap screws will be in single shear, tapped into
the flange and probably the splice plate too, for better bearing. I
can afford the extra machining work and custom fitting on one small
home project that only I will assemble.

My understanding is that if the lower tension splice plate has about
the same cross-sectional area as the flanges, it will stretch at close
enough to same rate to distribute the load on the bolts evenly instead
of shearing them progressively. I think I should use only one row to
minimize lost area. I've been using Grade 8 3/8" bolts which are
smaller than the AISC manual lists.

I couldn't find where I saw how to arrange rivet holes to minimize
both the loss of strength and width of the joint. In this instance I
think I can just make the lengthwise bolt spacing and splice plate
longer.
-jsw

"Jim Wilkins" wrote in message news
"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news
Is there a standard way to splice gantry hoist track made from two
channel sections? I'd like to make a 16' track from four 8' lengths of
C4 x 5.4 channel. The constraints are that the trolley wheels have to
roll inside the lower flange, which rules out this pattern:
https://www.researchgate.net/profile...101002@1470947
and a vertical plate or tee section extending below the lower flanges
can't block the HF 1 ton trolley. I've already turned its wheels down
to fit in 3" channel.

The immediate application has the splice plate suspended from a roof
beam and the outer ends supported by tripods, allowing 8' of clearance
for my bandsaw mill on one side and maneuvering room in the 4' wide
storage shed on the other, plus enough outside overhang to load the
cut timbers onto a narrow trailer.

The maximum load in this case will be under 500 lbs but I've been
struggling to use this problem as an exercise in designing a splice
that allows the full load capacity of the channels or 1 ton trolley on
a 16' span without interfering with the rolling trolley. I might be
able to shim up the lower fillets of a piece of scrap W6 x 9 beam so
the channel fits against the web and flanges. It looks like I have to
accept tapping the lower flanges of the channel and trimming the cap
screws flush inside.

-jsw
=============================================

I have no idea what "standard practice" is for this, but I'll toss out
some thoughts. First, cut one of the 8' channels in half and make three
splices, where each splice is in the middle of an uninterrupted span of
the backing channel by tapping one channel and using flat head bolts.
That keeps the central web thickness constant and lets one channel serve
as the splice plate for the other side. That would probably handle your
current load but maybe not the full 1 ton (I get a maximum stress of 3100
psi with a 250 lb load in the center of a single 8' span, so you have
plenty of safety margin for your 500 lb load). Second, if you cannot use
a tie plate below the joint because of interference with the trolley but
have room above, add a short section of channel on top of the splice
instead of a flat tie plate, with bolts through the webbing. Doing both
should get you a full strength joint. You may only need to do this above
the central splice, not all three. Of course, how big and how many bolts
and how long the upper channel should be is left as an exercise for the
reader :-).

--
Regards,
Carl Ijames

My notes from a while ago give ~25 KSI and a sag of 1 in 145 for one
16' length of 4x5.4 channel with a 1000 Lb center load. It likely came
from an on-line calculator. I could buy a single 20' beam for the
track but I couldn't handle it by myself; the four separate pieces are
reasonable to lift on a stepladder since this is a temporary outdoor
installation when I use the sawmill.

I did a quickie setup with 8' of channel extending out 4' from the
shed to cut one 750# log into two lighter pieces and realized that the
16' track I hadn't completed could be suspended from the shed roof
beam at its center splice, which makes everything simple. With the
shorter track I had to set up an end support to bring the log out,
remove the support to cut, replace it to flip the log and remove it
again to size the second piece, as the log had been roughly squared
oversize before drying. An 8' track over the saw would let it pass the
end support, the other 8' gives 4' to pick up the logs in the shed
plus 4' out the other side to put the finished beams on a trailer.

The center-supported track is easy (except for erecting it) but I want
to consider how to splice a single span so I don't do anything
regrettable when drilling for the center-supported splice plate. I
think I'll drill the web and leave the flanges alone.

For the single span I can have a tie plate below but not above the
lower flange, so the cap screws will be in single shear, tapped into
the flange and probably the splice plate too, for better bearing. I
can afford the extra machining work and custom fitting on one small
home project that only I will assemble.

My understanding is that if the lower tension splice plate has about
the same cross-sectional area as the flanges, it will stretch at close
enough to same rate to distribute the load on the bolts evenly instead
of shearing them progressively. I think I should use only one row to
minimize lost area. I've been using Grade 8 3/8" bolts which are
smaller than the AISC manual lists.

I couldn't find where I saw how to arrange rivet holes to minimize
both the loss of strength and width of the joint. In this instance I
think I can just make the lengthwise bolt spacing and splice plate
longer.
-jsw
=============================================

I think I misunderstood your layout so I better stop "helping" :-). The
link you posted to a splice diagram showed an I beam, so I assumed you were
using two C channels back to back to simulate an I beam with a thick
vertical web. If that's the case I still think my three splice instead of
one layout would be almost as easy to assemble and would be stronger. Just
for confirmation, the program I use (Engineering Power Tools, free or
shareware for more features at www.pwr-tools.com) gives peak stress 24.9 ksi
and 1.32" deflection for 1000 lbs at center and 16' span for one C channel.

--
Regards,
Carl Ijames

Jim - if you can stick with the 500 pound load, try a 16 ft. 2x12. The
calculator here predicts a max stress of 725 lbs and .323 in. deflection.
Add a couple of "angle irons" to the sides maybe?
You'd be happier with one of those calculators on your computer. They
are quite handy for something like this.

Hul

Jim Wilkins wrote:
Is there a standard way to splice gantry hoist track made from two
channel sections? I'd like to make a 16' track from four 8' lengths of
C4 x 5.4 channel. The constraints are that the trolley wheels have to
roll inside the lower flange, which rules out this pattern:
https://www.researchgate.net/profile...101002@1470947
and a vertical plate or tee section extending below the lower flanges
can't block the HF 1 ton trolley. I've already turned its wheels down
to fit in 3" channel.

The immediate application has the splice plate suspended from a roof
beam and the outer ends supported by tripods, allowing 8' of clearance
for my bandsaw mill on one side and maneuvering room in the 4' wide
storage shed on the other, plus enough outside overhang to load the
cut timbers onto a narrow trailer.

The maximum load in this case will be under 500 lbs but I've been
struggling to use this problem as an exercise in designing a splice
that allows the full load capacity of the channels or 1 ton trolley on
a 16' span without interfering with the rolling trolley. I might be
able to shim up the lower fillets of a piece of scrap W6 x 9 beam so
the channel fits against the web and flanges. It looks like I have to
accept tapping the lower flanges of the channel and trimming the cap
screws flush inside.

-jsw

"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news ...

I think I misunderstood your layout so I better stop "helping" :-).
The link you posted to a splice diagram showed an I beam, so I
assumed you were using two C channels back to back to simulate an I
beam with a thick vertical web. If that's the case I still think my
three splice instead of one layout would be almost as easy to
assemble and would be stronger. Just for confirmation, the program
I use (Engineering Power Tools, free or shareware for more features
at www.pwr-tools.com) gives peak stress 24.9 ksi and 1.32"
deflection for 1000 lbs at center and 16' span for one C channel.

--
Regards,
Carl Ijames

Your assumption is correct, two channels back to back with sections of
3/8" plate between them at the ends as hangers and as splices between
8' lengths. The 3" x 16' track I've been using to move logs in and out
of a shelter hangs from a roof beam at the center splice and this 4" x
16' one will too, in another shed that has become storage for squared
timbers. At this point creating a 16' free span gantry from the 4"
channels is just a design exercise, to see what I could make from my
materials.

I do like your idea of staggering the joints but it prevents
assembling the four channels as two separate 8' sections with higher
load capacity than the 3" channel I'm using now, one to load the
trailer and the other to unload and stack, and I don't have another
piece of 4" channel to cut in half. My 3" and 4" channels came from a
stack of used pallet rack parts at a surplus store that closed. The
nearest metal dealer recently quoted me $120 for a 4" x 20' channel,
cut in half so I could bring it home.

I have extra 3" channel and 3.5' of W6x9 beam that I picked up to
reinforce the splice somehow, perhaps bolted on top to go with a plate
under the tension flange, but that challenges my limited ability to
calculate and I have no idea how to figure the assembly's resistance
to buckling, I proof test my homebrew hoists on a stump with a 1000
Kg crane scale.

Thanks for confirming my numbers on the stress and deflection of the
4" channel. I'm never sure I didn't miss something with those
calculators. Is it true that the peak stress on two channels would be
half as much, and acceptable for the working load?

-jsw

"Hul Tytus" wrote in message
news
Jim - if you can stick with the 500 pound load, try a 16 ft. 2x12.
The
calculator here predicts a max stress of 725 lbs and .323 in.
deflection.
Add a couple of "angle irons" to the sides maybe?
You'd be happier with one of those calculators on your computer.
They
are quite handy for something like this.

Hul

I had cut some wide, 2.0" thick oak planks and did consider them to
strengthen the gantry track.
http://www.woodbin.com/calcs/sagulator/
"This calculator can also be used to measure beam deflection. Because
beams are typically positioned on edge, use "thickness" to represent
beam depth and "depth" to represent the thickness of the beam."
It accepts the non-standard dimensions of unplaned wood from my
sawmill.

The issue I didn't mention here is clearance height under the existing
shed roof beams, as the timbers are stacked almost as high as I could
get them with 3" channel for the gantry track.
-jsw

"Jim Wilkins" wrote in message news
"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news ...

I think I misunderstood your layout so I better stop "helping" :-). The
link you posted to a splice diagram showed an I beam, so I assumed you
were using two C channels back to back to simulate an I beam with a thick
vertical web. If that's the case I still think my three splice instead of
one layout would be almost as easy to assemble and would be stronger.
Just for confirmation, the program I use (Engineering Power Tools, free or
shareware for more features at www.pwr-tools.com) gives peak stress 24.9
ksi and 1.32" deflection for 1000 lbs at center and 16' span for one C
channel.

--
Regards,
Carl Ijames

Your assumption is correct, two channels back to back with sections of
3/8" plate between them at the ends as hangers and as splices between
8' lengths. The 3" x 16' track I've been using to move logs in and out
of a shelter hangs from a roof beam at the center splice and this 4" x
16' one will too, in another shed that has become storage for squared
timbers. At this point creating a 16' free span gantry from the 4"
channels is just a design exercise, to see what I could make from my
materials.

I do like your idea of staggering the joints but it prevents
assembling the four channels as two separate 8' sections with higher
load capacity than the 3" channel I'm using now, one to load the
trailer and the other to unload and stack, and I don't have another
piece of 4" channel to cut in half. My 3" and 4" channels came from a
stack of used pallet rack parts at a surplus store that closed. The
nearest metal dealer recently quoted me $120 for a 4" x 20' channel,
cut in half so I could bring it home.

I have extra 3" channel and 3.5' of W6x9 beam that I picked up to
reinforce the splice somehow, perhaps bolted on top to go with a plate
under the tension flange, but that challenges my limited ability to
calculate and I have no idea how to figure the assembly's resistance
to buckling, I proof test my homebrew hoists on a stump with a 1000
Kg crane scale.

Thanks for confirming my numbers on the stress and deflection of the
4" channel. I'm never sure I didn't miss something with those
calculators. Is it true that the peak stress on two channels would be
half as much, and acceptable for the working load?

-jsw
================================================== =

First, the usual disclaimer, I'm not an engineer and this isn't professional
advice :-). But I've read a lot and done a lot of calculations on
mechanical prototypes I was designing that worked as designed. Yes, if you
put two channels in parallel with the same total load the peak stress is cut
in half. For 1000 lb concentrated at the center of an 8' span a single 4"
channel will deflect 0.165" and peak stress will be 12.5 ksi, and a 3"
channel will deflect 0.383" and have peak stress 21.7 ksi. Adding a second
4" channel cuts the deflection to 0.083" and the peak stress to 6.3 ksi, and
the doubled 3" deflection and stress become 0.191" and 11 ksi. That says
that the 4" channel is almost twice as strong so one 4" channel is worth
almost two 3" channels. How about if you bolt a 4' piece and an 8' piece of
4" channel to an 8' piece, back to back with the ends flush at one end.
That gives you your desired doubled 4" x 8' channel with 4' extra sticking
out one end, which doesn't hurt so long as you have room in your shed for it
to still fit. Then take the other 4' x 4" channel and bolt it with ends
flush to the other 8' channel, and then bolt on a 4' piece of 3" channel
with the bottom flanges aligned so the crane trolley can roll the entire
length. If your doubled 3" channel is sufficient now, this should be more
than enough, and you can unbolt the 3" channel and bolt together the 4"
assemblies to make the full 16' span with staggered joints.

Whenever you have a live load, like people walking on a deck or lifting a
load that is moving and bouncing, the usual rule of thumb is to triple the
load to calculate the peak stress. Then apply whatever safety factor you
feel appropriate. For something used once with no one anywhere near that
can get hurt I might go down to 2x but for this I'd go at least 4x -
remember, I'm not a professional. So if your beam steel is rated at 25 ksi
yield I'd keep the peak stress below 25 ksi/12 = 2.1 ksi, maybe less.
Others might say that is way too conservative but I never, ever want
anything I'm walking under to fall on me :-). Running those numbers in
reverse for the 4" channels, 2.1 ksi / 6.3 ksi * 1000 lbs = 333 lbs for a
rated load for your 8' span 4" assembly. I said I was conservative.

--
Regards,
Carl Ijames

"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news
"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news ...

I think I misunderstood your layout so I better stop "helping" :-).
The link you posted to a splice diagram showed an I beam, so I
assumed you were using two C channels back to back to simulate an I
beam with a thick vertical web. If that's the case I still think
my three splice instead of one layout would be almost as easy to
assemble and would be stronger. Just for confirmation, the program
I use (Engineering Power Tools, free or shareware for more features
at www.pwr-tools.com) gives peak stress 24.9 ksi and 1.32"
deflection for 1000 lbs at center and 16' span for one C channel.

--
Regards,
Carl Ijames

Your assumption is correct, two channels back to back with sections
of
3/8" plate between them at the ends as hangers and as splices
between
8' lengths. The 3" x 16' track I've been using to move logs in and
out
of a shelter hangs from a roof beam at the center splice and this 4"
x
16' one will too, in another shed that has become storage for
squared
timbers. At this point creating a 16' free span gantry from the 4"
channels is just a design exercise, to see what I could make from my
materials.

I do like your idea of staggering the joints but it prevents
assembling the four channels as two separate 8' sections with higher
load capacity than the 3" channel I'm using now, one to load the
trailer and the other to unload and stack, and I don't have another
piece of 4" channel to cut in half. My 3" and 4" channels came from
a
stack of used pallet rack parts at a surplus store that closed. The
nearest metal dealer recently quoted me $120 for a 4" x 20' channel,
cut in half so I could bring it home.

I have extra 3" channel and 3.5' of W6x9 beam that I picked up to
reinforce the splice somehow, perhaps bolted on top to go with a
plate
under the tension flange, but that challenges my limited ability to
calculate and I have no idea how to figure the assembly's resistance
to buckling, I proof test my homebrew hoists on a stump with a 1000
Kg crane scale.

Thanks for confirming my numbers on the stress and deflection of the
4" channel. I'm never sure I didn't miss something with those
calculators. Is it true that the peak stress on two channels would
be
half as much, and acceptable for the working load?

-jsw
================================================== =

First, the usual disclaimer, I'm not an engineer and this isn't
professional advice :-). But I've read a lot and done a lot of
calculations on mechanical prototypes I was designing that worked as
designed. Yes, if you put two channels in parallel with the same
total load the peak stress is cut in half. For 1000 lb concentrated
at the center of an 8' span a single 4" channel will deflect 0.165"
and peak stress will be 12.5 ksi, and a 3" channel will deflect
0.383" and have peak stress 21.7 ksi. Adding a second 4" channel
cuts the deflection to 0.083" and the peak stress to 6.3 ksi, and
the doubled 3" deflection and stress become 0.191" and 11 ksi. That
says that the 4" channel is almost twice as strong so one 4" channel
is worth almost two 3" channels. How about if you bolt a 4' piece
and an 8' piece of 4" channel to an 8' piece, back to back with the
ends flush at one end. That gives you your desired doubled 4" x 8'
channel with 4' extra sticking out one end, which doesn't hurt so
long as you have room in your shed for it to still fit. Then take
the other 4' x 4" channel and bolt it with ends flush to the other
8' channel, and then bolt on a 4' piece of 3" channel with the
bottom flanges aligned so the crane trolley can roll the entire
length. If your doubled 3" channel is sufficient now, this should
be more than enough, and you can unbolt the 3" channel and bolt
together the 4" assemblies to make the full 16' span with staggered
joints.

I could if I found some extra 4" channel, but I have only four 8'
pieces and want to pair them into two separate gantries, one to load
and the other to unload the trailer. For the squared timber shed
application two doubled 8' channels joined at a suspended splice plate
is the easy answer. The 3/8" plates between the outer ends of the
channels are the cut-off end tabs that attached the channel to the
pallet rack columns, and make perfect centerline hangers to shackle
the ends to the tripods. I have a scrap 3/8" plate that's a good size
for the center splice and hanger without cutting it.


Whenever you have a live load, like people walking on a deck or
lifting a load that is moving and bouncing, the usual rule of thumb
is to triple the load to calculate the peak stress. Then apply
whatever safety factor you feel appropriate. For something used
once with no one anywhere near that can get hurt I might go down to
2x but for this I'd go at least 4x - remember, I'm not a
professional. So if your beam steel is rated at 25 ksi yield I'd
keep the peak stress below 25 ksi/12 = 2.1 ksi, maybe less. Others
might say that is way too conservative but I never, ever want
anything I'm walking under to fall on me :-). Running those numbers
in reverse for the 4" channels, 2.1 ksi / 6.3 ksi * 1000 lbs = 333
lbs for a rated load for your 8' span 4" assembly. I said I was
conservative.

--
Regards,
Carl Ijames

I have one manual chain and one electric cable hoist. The manual one
is much too slow to shock load the track. The HF 1300# electric hoist
starts with a sharp jerk as you mentioned, but the impulse doesn't
seem as bad as the hoist nears its capacity. I bought it so I could
lift and stack the timbers from a distance in case the loaded gantry
collapsed.

The HF hoist itself works fine but its pipe mount is sketchy and
completely unsuited to being suspended from a gantry trolley without
some custom metalwork. I welded a squared U frame that bolts to the
hoist from heavy angle and made axles and wheels that ride on the 3"
channel track, though it turns out not on the 4" channel. That was the
2015 project where I asked about press-fitting bearings into precisely
bored recesses.
-jsw

"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news
....and then bolt on a 4' piece of 3" channel with the bottom
flanges aligned so the crane trolley can roll the entire length.

Wouldn't an asymmetrical section tend to twist and buckle as its
deflection increased?

These gantries are set up temporarily outdoors on the bare ground and
need a leveling adjustment to keep the load from moving by itself,
either a tripod whose legs I can move in or out, or a large forged
turnbuckle hung from a braced post.
..
In both cases the channel ends can rotate to some extent, more so with
the tripod where the channels hang from chain. A stiffer top
connection that constrained channel rotation wouldn't adapt to the
uneven ground, plus it would add an unknown amount of cantilever
loading that reduces the column strength of the tripod legs which are
8' chain link fence posts or 2" x 10' EMT for lightness. A stronger
tripod of 2" x 10' water pipe legs is too top-heavy to set up safely.

-jsw

On Sat, 2 Sep 2017 10:30:30 -0400, "Jim Wilkins"
wrote:

Is there a standard way to splice gantry hoist track made from two
channel sections? I'd like to make a 16' track from four 8' lengths of
C4 x 5.4 channel.

Have you tried calling OSHA about it? They _love_ this kind of thing.
gd&r

So you're butting C channel back to back and end to end to get the
length and profile you want? If I had 6 pieces, I'd think about
bolting (and welding?) two of them on top offset by 4', but I'm not
sure I'd call it 1T-ready, since it only adds single flange support.


The constraints are that the trolley wheels have to
roll inside the lower flange, which rules out this pattern:
https://www.researchgate.net/profile...101002@1470947

Resolves to https://www.researchgate.net/profile/Abbas_Rezaeian3 .
But, looking for the word "channel", I found the paper, clicked to DL,
and it brought up the abstract with jpgs. He bolts the **** out of
that I-beam, doesn't he?


and a vertical plate or tee section extending below the lower flanges
can't block the HF 1 ton trolley. I've already turned its wheels down
to fit in 3" channel.

The immediate application has the splice plate suspended from a roof
beam and the outer ends supported by tripods, allowing 8' of clearance
for my bandsaw mill on one side and maneuvering room in the 4' wide
storage shed on the other, plus enough outside overhang to load the
cut timbers onto a narrow trailer.

The center support helps immensely, depending on the amount of support
it can lend.


The maximum load in this case will be under 500 lbs but I've been
struggling to use this problem as an exercise in designing a splice
that allows the full load capacity of the channels or 1 ton trolley on
a 16' span without interfering with the rolling trolley. I might be
able to shim up the lower fillets of a piece of scrap W6 x 9 beam so
the channel fits against the web and flanges. It looks like I have to
accept tapping the lower flanges of the channel and trimming the cap
screws flush inside.

Will there be clearance space to add web splice plates since you
already pared down the wheels for the narrower beam flanges?

--
Do not let your fire go out, spark by irreplacable spark.

In the hopeless swamps of the not quite, the not yet, and
the not at all, do not let the hero in your soul perish
and leave only frustration for the life you deserved, but
never have been able to reach.

The world you desire can be won, it exists, it is real,
it is possible, it is yours.
-- Ayn Rand

On Sat, 2 Sep 2017 19:57:57 -0400, "Jim Wilkins"
wrote:

"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news ...

I think I misunderstood your layout so I better stop "helping" :-).
The link you posted to a splice diagram showed an I beam, so I
assumed you were using two C channels back to back to simulate an I
beam with a thick vertical web. If that's the case I still think my
three splice instead of one layout would be almost as easy to
assemble and would be stronger. Just for confirmation, the program
I use (Engineering Power Tools, free or shareware for more features
at www.pwr-tools.com) gives peak stress 24.9 ksi and 1.32"
deflection for 1000 lbs at center and 16' span for one C channel.

--
Regards,
Carl Ijames

Your assumption is correct, two channels back to back with sections of
3/8" plate between them at the ends as hangers and as splices between

Oh, right. Using C, you can shim/splice between for center strength,
then reposition the extra washers on the trolley to compensate.


--
Do not let your fire go out, spark by irreplacable spark.

In the hopeless swamps of the not quite, the not yet, and
the not at all, do not let the hero in your soul perish
and leave only frustration for the life you deserved, but
never have been able to reach.

The world you desire can be won, it exists, it is real,
it is possible, it is yours.
-- Ayn Rand

"Larry Jaques" wrote in message
...
On Sat, 2 Sep 2017 10:30:30 -0400, "Jim Wilkins"
wrote:


Will there be clearance space to add web splice plates since you
already pared down the wheels for the narrower beam flanges?


A 3/8" thick plate or turnbuckle eye between the channels is included
in the original design.

That (slightly) modified trolley is derated to stay with 3" channel
unless I need to move a light load like the 500 Lb squared beams.
This tells me how much things really weigh, relative to the proof load
even if it isn't accurate:
https://www.amazon.com/precision-Sta...00WO29ZGM?th=1
Do you suppose anyone ever clicked "Add to Wedding Registry"?

I'll buy a new 1 ton trolley for the 4" channel. Moving logs or beams
from one shed to the sawmill and then into another takes two gantry
tracks and trolleys anyway.

Sometimes these small Amazon storefronts offer strange assortments of
unusual stuff. For the secret agent in you:
https://www.amazon.com/iDili-Stainle...4461903&sr=8-6

For the mad scientist in me:
https://www.amazon.com/iDili-Update-...4461903&sr=8-7

-[0wcUyc14=

"Jim Wilkins" wrote in message news
"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news
....and then bolt on a 4' piece of 3" channel with the bottom flanges
aligned so the crane trolley can roll the entire length.

Wouldn't an asymmetrical section tend to twist and buckle as its
deflection increased?

These gantries are set up temporarily outdoors on the bare ground and
need a leveling adjustment to keep the load from moving by itself,
either a tripod whose legs I can move in or out, or a large forged
turnbuckle hung from a braced post.
..
In both cases the channel ends can rotate to some extent, more so with
the tripod where the channels hang from chain. A stiffer top
connection that constrained channel rotation wouldn't adapt to the
uneven ground, plus it would add an unknown amount of cantilever
loading that reduces the column strength of the tripod legs which are
8' chain link fence posts or 2" x 10' EMT for lightness. A stronger
tripod of 2" x 10' water pipe legs is too top-heavy to set up safely.

-jsw
===============================================

Yes, twisting is always a concern and my suggestion would probably make it
more susceptible. Whether or not that would be the limiting factor in
loading, I can't say.

--
Regards,
Carl Ijames

Jim - sounds like the 3 or 4 inch channels are the best fit considering
the dimensions of the shed.

Hul

Jim Wilkins wrote:
"Hul Tytus" wrote in message
news
Jim - if you can stick with the 500 pound load, try a 16 ft. 2x12.
The
calculator here predicts a max stress of 725 lbs and .323 in.
deflection.
Add a couple of "angle irons" to the sides maybe?
You'd be happier with one of those calculators on your computer.
They
are quite handy for something like this.

Hul

I had cut some wide, 2.0" thick oak planks and did consider them to
strengthen the gantry track.
http://www.woodbin.com/calcs/sagulator/
"This calculator can also be used to measure beam deflection. Because
beams are typically positioned on edge, use "thickness" to represent
beam depth and "depth" to represent the thickness of the beam."
It accepts the non-standard dimensions of unplaned wood from my
sawmill.

The issue I didn't mention here is clearance height under the existing
shed roof beams, as the timbers are stacked almost as high as I could
get them with 3" channel for the gantry track.
-jsw

"Hul Tytus" wrote in message
news
Jim - sounds like the 3 or 4 inch channels are the best fit
considering
the dimensions of the shed.

Hul

In case you haven't followed the disconnected details, I have a good
scheme to erect gantry hoist tracks 8' out and in from the roof beam
over the shed entrance. The beam was sized to support its share of a
foot of solid ice on the roof, 60 Lbs/sq'.

I'm less sure of how I might splice the four 4" x 8' channels into a
16' track that isn't supported in the middle, not that I need to right
now, but I don't want to rule it out in the future by drilling holes
for the center-supported splice plate that would interfere with an
unsupported splice. My question was a fishing trip for ideas.

I think the answer is to drill the web to bolt to the center
splice/hanger plate and leave the flanges untouched for now.

-jsw

On Sun, 3 Sep 2017 14:30:17 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Sat, 2 Sep 2017 10:30:30 -0400, "Jim Wilkins"
wrote:


Will there be clearance space to add web splice plates since you
already pared down the wheels for the narrower beam flanges?


A 3/8" thick plate or turnbuckle eye between the channels is included
in the original design.

That thought completely missed me the first run through, likely
because you said you turned the wheels to narrow it. It evidently
narrowed my 3D mockup.


That (slightly) modified trolley is derated to stay with 3" channel
unless I need to move a light load like the 500 Lb squared beams.
This tells me how much things really weigh, relative to the proof load
even if it isn't accurate:
https://www.amazon.com/precision-Sta...00WO29ZGM?th=1
Do you suppose anyone ever clicked "Add to Wedding Registry"?

She's a dilly! Boilerplate web design. What can you say? Or maybe
Chinese Sumo wrestlers are picky about their wives' weight.

I couldn't remember the word "sumo" so I googled "japanese wrestler".
One of the pics which came up was Asuka, a female, which led to the
red latex EVA plug suits. I'm happy to have gone off on that tangent.
http://tinyurl.com/y9xxcf29 http://tinyurl.com/ycuexyyl
http://tinyurl.com/ybl9kbng Isn't cosplay wonderful?


I'll buy a new 1 ton trolley for the 4" channel. Moving logs or beams
from one shed to the sawmill and then into another takes two gantry
tracks and trolleys anyway.

So are you making a 16' track, or keeping two 8-footers? I'm getting
dizzy here.


Sometimes these small Amazon storefronts offer strange assortments of
unusual stuff. For the secret agent in you:
https://www.amazon.com/iDili-Stainle...4461903&sr=8-6

That won't do at all, though it's lovely. Opposing warlord guards on
the castle wall would see a -polished- grappling hook, so it needs to
be black. But I already have one, hanging by the front door in case
the dam upstream gives out and I need to grapple into heights in a
hurry. Now to lose 40# so my arms will lift me... snort

Look at this inexpensive darling: http://tinyurl.com/ybp2rgxu


For the mad scientist in me:
https://www.amazon.com/iDili-Update-...4461903&sr=8-7

Idly fascinating.

--
Do not let your fire go out, spark by irreplacable spark.

In the hopeless swamps of the not quite, the not yet, and
the not at all, do not let the hero in your soul perish
and leave only frustration for the life you deserved, but
never have been able to reach.

The world you desire can be won, it exists, it is real,
it is possible, it is yours.
-- Ayn Rand

Jim - for the free center 16 ft version, take a look at an I beam with the
two channel (4 all total) pieces within it in place of the 3/8 in. center
support. Cleareance on the bottom could be a problem and the lack of a
horizontal surface on the inside of the I beam flanges too. But an I
beam in the center gives a greater strength for the greater stresses. You
could get a 6 ft I beam and make it even longer...

Hul

Jim Wilkins wrote:
"Hul Tytus" wrote in message
news
Jim - sounds like the 3 or 4 inch channels are the best fit
considering
the dimensions of the shed.

Hul

In case you haven't followed the disconnected details, I have a good
scheme to erect gantry hoist tracks 8' out and in from the roof beam
over the shed entrance. The beam was sized to support its share of a
foot of solid ice on the roof, 60 Lbs/sq'.

I'm less sure of how I might splice the four 4" x 8' channels into a
16' track that isn't supported in the middle, not that I need to right
now, but I don't want to rule it out in the future by drilling holes
for the center-supported splice plate that would interfere with an
unsupported splice. My question was a fishing trip for ideas.

I think the answer is to drill the web to bolt to the center
splice/hanger plate and leave the flanges untouched for now.

-jsw

"Hul Tytus" wrote in message
news
Jim - for the free center 16 ft version, take a look at an I beam
with the
two channel (4 all total) pieces within it in place of the 3/8 in.
center
support. Cleareance on the bottom could be a problem and the lack of
a
horizontal surface on the inside of the I beam flanges too. But an I
beam in the center gives a greater strength for the greater
stresses. You
could get a 6 ft I beam and make it even longer...

Hul

I bought a 3.5' length of W6 x 9 (?) for the purpose when I got the
channel. This morning I used the 25% Labor Day coupon on another HF 1
Ton Push Trolley which fits pretty well on the 4" channels with the W6
sandwiched between. Spacing the channels 3/8" apart moves them off the
lower web fillet. The flanges are parallel, not tapered. It helps to
finally have all the pieces to play with.

I get a maximum stress of 17.5 KSI for a W6 x 9 16' long, center
loaded with 2000 Lbs, compared to 12.5 KSI for two parallel 4"
channels. I could abut the upper channel flanges and reinforce the
tension side joint with a splice plate, then struggle with moment of
inertia calculations for the combination.
thanks
-jsw

Jim - you said that the flanges are parrallel; is that the channel stock
or the I beam?

Hul

Jim Wilkins wrote:
"Hul Tytus" wrote in message
news
Jim - for the free center 16 ft version, take a look at an I beam
with the
two channel (4 all total) pieces within it in place of the 3/8 in.
center
support. Cleareance on the bottom could be a problem and the lack of
a
horizontal surface on the inside of the I beam flanges too. But an I
beam in the center gives a greater strength for the greater
stresses. You
could get a 6 ft I beam and make it even longer...

Hul

I bought a 3.5' length of W6 x 9 (?) for the purpose when I got the
channel. This morning I used the 25% Labor Day coupon on another HF 1
Ton Push Trolley which fits pretty well on the 4" channels with the W6
sandwiched between. Spacing the channels 3/8" apart moves them off the
lower web fillet. The flanges are parallel, not tapered. It helps to
finally have all the pieces to play with.

I get a maximum stress of 17.5 KSI for a W6 x 9 16' long, center
loaded with 2000 Lbs, compared to 12.5 KSI for two parallel 4"
channels. I could abut the upper channel flanges and reinforce the
tension side joint with a splice plate, then struggle with moment of
inertia calculations for the combination.
thanks
-jsw

Jim - two of the channels "converted" to an I beam 4 in. high, 1.584 * 2
inches wide with a flange thickness of .296 inches and a web thickness of
..184 * 2 in. and 16 ft long showed a max stress of 25064 psi & 1.281 in.
deflection with a 2000 lbs center loaded weight. You didn't use the
"uniform loading" option, by any chance?

Hul

Jim Wilkins wrote:
"Hul Tytus" wrote in message
news
Jim - for the free center 16 ft version, take a look at an I beam
with the
two channel (4 all total) pieces within it in place of the 3/8 in.
center
support. Cleareance on the bottom could be a problem and the lack of
a
horizontal surface on the inside of the I beam flanges too. But an I
beam in the center gives a greater strength for the greater
stresses. You
could get a 6 ft I beam and make it even longer...

Hul

I bought a 3.5' length of W6 x 9 (?) for the purpose when I got the
channel. This morning I used the 25% Labor Day coupon on another HF 1
Ton Push Trolley which fits pretty well on the 4" channels with the W6
sandwiched between. Spacing the channels 3/8" apart moves them off the
lower web fillet. The flanges are parallel, not tapered. It helps to
finally have all the pieces to play with.

I get a maximum stress of 17.5 KSI for a W6 x 9 16' long, center
loaded with 2000 Lbs, compared to 12.5 KSI for two parallel 4"
channels. I could abut the upper channel flanges and reinforce the
tension side joint with a splice plate, then struggle with moment of
inertia calculations for the combination.
thanks
-jsw

"Hul Tytus" wrote in message
news
Jim - two of the channels "converted" to an I beam 4 in. high, 1.584
* 2
inches wide with a flange thickness of .296 inches and a web
thickness of
.184 * 2 in. and 16 ft long showed a max stress of 25064 psi & 1.281
in.
deflection with a 2000 lbs center loaded weight. You didn't use the
"uniform loading" option, by any chance?

Hul


Those are the values I got for one center loaded 4" x 16' channel,
which I then halved for two in parallel. Thanks for checking.

The flanges of this W6x9 beam are very slightly tapered by about
1/32", AFAICT through the rust. They are a reasonably good match to
the outer taper on the channel if I increase the center spacer to 3/4"
which aligns the outer edges of the beam and channel. There's the rust
and some welding and torch cutting flash to grind off before fitting
them together more precisely, but it looks promising. I could suspend
the W6x9 upper flange from the shed roof beam with U bolts and use the
one assembly for both applications, if properly reinforced for both
sagging and hogging.

I should add a warning that a gantry track suspended from tripods can
collapse in many ways from single point failures, such as a leg
sinking or the load swaying. The soil here is compacted glacial till
with a good bearing strength and I have large trees to tie the tripod
tops to. I tested the concept free-standing but have used it only
where I had trees and a shed to stabilize the track and tripods. Pipe
and tubing ends sink into the ground very easily without my
custom-machined ball joints and spreader plates.
-jsw

"Jim Wilkins" wrote in message
news
"Hul Tytus" wrote in message
news
Jim - two of the channels "converted" to an I beam 4 in. high,
1.584 * 2
inches wide with a flange thickness of .296 inches and a web
thickness of
.184 * 2 in. and 16 ft long showed a max stress of 25064 psi &
1.281 in.
deflection with a 2000 lbs center loaded weight. You didn't use the
"uniform loading" option, by any chance?

Hul


Those are the values I got for one center loaded 4" x 16' channel,
which I then halved for two in parallel. Thanks for checking.


Oops, I misread my tabulation. The center load was 1000 lbs.
-jsw