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View Full Version : Mini gantry - ideas and advice wanted...



Davek0974
01-28-2010, 03:05 PM
Hi all,

i need to build a mini gantry to enable me to swap my overweight rotary table between milling machines without rupturing something i may want later in life :D

I already have a beam with trolley and a chainfall hoist but it can only move in one axis - from the mill bed to the rear wall, i want to mobilise it in the left / right axis so i can shift the load from one mill to the next etc.

Its all lightweight stuff, max load only needs to be about 100kg and the beam is made from 2 lengths of 20mm box section welded one on top of the other.

I have some spare 2x2" angle iron which would be good for runners.

What i am looking for are ideas on how to make a beam into a trolley that wont twist and fall off the runners/rails. Would turning grooves into the wheels and running on the edge of the angle do it? I'm guessing the wheels will need to be a distance apart for guidance / stability??

Any tips or pictures??

Thanks in advance
Dave

ulav8r
01-28-2010, 05:17 PM
A few years back on this forum or PM, there was shown a gantry that pivoted on one end, the other end was on a track suspended from the ceiling. Depending on spacing of the two machines, it might work for you.

Will you need to clear light fixtures? Could a separate rail be added to connect the two mills? That would require a second hoist or a way to easily transfer the hoist from track to track. Or use a roller table to transfer the table, make it a height that requires the least adjustment of the mill tables' height.

Tinkerer
01-28-2010, 05:51 PM
Make a Zip Line 3/8" steel cable... a turn buckle and a couple of anchor plates and a two wheeled pulley with a eye hook. Don't see why it would not work. And it's light and cheap to boot. ;)

Doozer
01-28-2010, 06:13 PM
Given your application, have you considered a die cart?
If it is a knee mill, you could use a regular cart.

--Doozer

The Artful Bodger
01-28-2010, 07:35 PM
What i am looking for are ideas on how to make a beam into a trolley that wont twist and fall off the runners/rails. Would turning grooves into the wheels and running on the edge of the angle do it? I'm guessing the wheels will need to be a distance apart for guidance / stability??

Any tips or pictures??

Thanks in advance
Dave

I have seen angle iron used for a trolley rail, the angle iron was mounted with the corner upside (i.e. 45 degree sides) and the trolley had ball races mounted at 90 degrees to each other to hang over the rail.

Arcane
01-28-2010, 09:15 PM
Also, consider using one of those patient lifts, the kind that look like miniature engine hoists. I have one that breaks down into two pieces and it's light and easy to handle with a 400# SWL. Their portability is very convenient!
http://patientlift.ca/images/drivemanual.gif

tumutbound
01-28-2010, 09:49 PM
A few years back on this forum or PM, there was shown a gantry that pivoted on one end, the other end was on a track suspended from the ceiling. Depending on spacing of the two machines, it might work for you.


This (http://www.homemetalshopclub.org/projects/crane/crane.html) the one you were thinking of?

Bob Ford
01-28-2010, 11:46 PM
Dave

Have a look at this works great for me. http://bbs.homeshopmachinist.net/showthread.php?t=35492

Bob

Forrest Addy
01-29-2010, 12:23 AM
Hard to keep the discussion straight. A gantry is not another word for crane, it's a specific type of crane as is a jib crane, bridge crane etc. What Dave seem to decribe as his present hoistng arrangement is a ceiling suspended monorail crane and I think he might be exploring a bridge or overhead crane whose "X - Y" travel will cover a larger rectangular access area.

A gantry crane has a single beam supported at each end by "A" frames often furnished with casters or ral wheels for longdudinal motion. A jib crane consists of a vwertial axis of rotation and a horizontal beam either cantilevered, braced, or vanged. Its acces is arc shaped. There are two kind: one swivels on a kingpost needing no upper bearing and the other swivels from a column or other building structure.

Then there are wall cranes, portal cranes of dozens of varations etc.

My probably too fussy point is I was thrown by the vocabulary.

Davek0974
01-29-2010, 02:22 AM
Hard to keep the discussion straight. A gantry is not another word for crane, it's a specific type of crane as is a jib crane, bridge crane etc. What Dave seem to decribe as his present hoistng arrangement is a ceiling suspended monorail crane and I think he might be exploring a bridge or overhead crane whose "X - Y" travel will cover a larger rectangular access area.

A gantry crane has a single beam supported at each end by "A" frames often furnished with casters or ral wheels for longdudinal motion. A jib crane consists of a vwertial axis of rotation and a horizontal beam either cantilevered, braced, or vanged. Its acces is arc shaped. There are two kind: one swivels on a kingpost needing no upper bearing and the other swivels from a column or other building structure.

Then there are wall cranes, portal cranes of dozens of varations etc.

My probably too fussy point is I was thrown by the vocabulary.

Thats the one - Overhead crane, presently resting on a roof truss at one end and the wall plate at the other. The roof is an apex type with angle iron trusses. I do indeed want to cover a larger area by moving in X & Y axes.

There is no floor room for a patient lift, i already have an engine hoist i cant get in easily! The distance on X is about 6' and on Y about 5'. The wall wont take a wall crane and i dont want to go to the floor for support, floorspace is expensive.

As i say, the beam is built i just need to satisfy myself a way of keeping the trolley above my head as i can see a poor design twisting and falling, would grooved runners on the edge of the angle work, maybe 12" apart on each end?

Something nice and simple.

BTW there are some fantastic ideas here so far, thanks

Dave

The Artful Bodger
01-29-2010, 02:58 AM
Dave, by poor design allowing twisting do you mean the mobile cross beam getting skewed so that there is a 'Z' shape instead of an 'H'?

If thats the concern you could use cables and pullies for a 'cats cradle' to keep things aligned.

Davek0974
01-29-2010, 03:25 AM
thats the main worry, the carriage twisting and falling.

cables would be good but heading towards complicated, thats why i was thinking grooved or heavily flanged wheels running on th edge of the angle??

dave

The Artful Bodger
01-29-2010, 03:31 AM
thats the main worry, the carriage twisting and falling.

cables would be good but heading towards complicated, thats why i was thinking grooved or heavily flanged wheels running on th edge of the angle??

dave


Yes, but the you only need four pullies and it has the advantage that if the load is at one end of the beam when you drag on it the cables transfer some of your effort directly towards moving the other end too.

Did you see my post about pairs of ball races resting on the angle iron?

The Artful Bodger
01-29-2010, 03:42 AM
Here is the basic cat's cradle, without something like this or some mechanical linkage moving one end of the beam does not really encourage the other end to move.

http://farm5.static.flickr.com/4072/4313527258_4e50128911_o.jpg




This is how I thought you could make the trolleys, sorry about non-right angles but it was a quick job in Paint.

http://farm3.static.flickr.com/2677/4312791093_07e66c4a9a_o.jpg

Davek0974
01-29-2010, 04:16 AM
Would the angle trolleys be sufficient on their own or will i need the cats cradle setup too, i can see the benefit as it similar to my old drawing board rule, but will both be needed?

dave

form_change
01-29-2010, 04:50 AM
This sort of thing might be worth considering -
http://www.chinalifting.com/english/products_detail.php?class=2&id=32
Places around here use them (like car plants) because they are fine for light loads and you can also use them as an air main. (not necessarily this brand though) The rollers on top are far enough apart that you can weld a fin on and suspend it with that.

Davek0974
01-29-2010, 05:16 AM
Possibly, the pipe trolley is another good idea.

I think the best option so far is to have the cats cradle cable setup with one trolley running along the L of one rail using grooved pulleys or the angle bearing style. Then the other trolley can run on flat wheels on the flat of the other rail to allow for any slight change in track dimension.

So its located on one side but the cable ensures the other side follows acurately.

Does that sound a good setup??

Dawai
01-29-2010, 06:32 AM
Years ago, John S came up with a crane that bolted to the rear knuckle on a bridgeport.
http://bbs.homeshopmachinist.net/showthread.php?t=964&highlight=john+stevenson+crane

Pictures are dead links..

It swiveled and swung a nice arc around the machine.

Two of them and a "cart" to store the rt on is what I had for a while. It consisted of a bushing that went into the casting in the knuckle, a loop, a vertical riser, horizontal riser and a HF winch.

I purchased a 4 jaw chuck for the lathe, now that stinkin thing hanging the L00 chuck on the leblond was harder than the RT. (scared of dented ways). I modified to a crane mounted on a hbeam press. A hf electric hoist and I have used it for years now.

NOW? I moved the lathe back to it's original location and I am back to square one. Sold the big Rtable since I have a cnc.. rarely used the fourth axis. Never used the vertical axis.

Bolt the crane to something that don't move easily.

JMS6449
01-29-2010, 07:53 AM
The boom mounted on the back knuckle of the BP or a simple table mounted gantry. KISS

Davek0974
01-29-2010, 08:31 AM
I did see the BP boom job, in my case if it were long enough to reach the other mill, it would hit the roof trusses.

My device has to fit up inside the gap between one truss and the end wall, headroom is very limited below the trusses.

Dawai
01-29-2010, 09:01 AM
I have paintline track, made into trolleys up in several places in the shop.

It, by itself must be supported every couple of feet, I took one piece thou and backed it up with a 3x4" angle and have trolleyed car engines easily without any deformation on the track.

Barn door track at tractor supply corp (TSC) is similar.. lighter perhaps. Still made to hang a heavy door on.

I too desire a light simple to create gantry, or lift to use outside and inside.. easy to take down and put up.. Problem is, I normally overbuild things to the point where I need a forklift to move it. I got a huge aframe outside with Ibeam, we loaded the 24" cinncinatti lathe with it recently. (stress test?)

When you put wheels, rollers on the legs of a aframe it loses all rigidity, they want to run bow-legged... a angle track on the floor means a dedicated work area..

If you got floorspace, a $195 engine crane is hard to beat.. I got mine mounted on a swivel on the one ton for outside picks. Some fold up quite small when not needed.

Davek0974
01-29-2010, 09:05 AM
If you got floorspace, a $195 engine crane is hard to beat.. I got mine mounted on a swivel on the one ton for outside picks. Some fold up quite small when not needed.

Already got one, it lives outside in the garden as i dont have the floorspace now.

What is paintline track?

Boucher
01-29-2010, 09:33 AM
This is a wheel chair lift adapted to pick up 8" mill vice and 10" rotary table. It was not finished as shown. (Needed gusset underneath)
http://i109.photobucket.com/albums/n50/boucherbyron/P9290012.jpg
I wound up moving the Mill enough that it would not reach. I guess the moral to this story is be sure locations are settled before investing too much effort in a lift to service them.

Doozer
01-29-2010, 09:34 AM
http://www.phc-online.com/v/vspfiles/photos/Hoyer_C-HLA-2.jpg

Hoyer Lifts for hospital patients lift 400lbs and leg spread is adjustable.
Perfect for moving vises and RT's. Can find them on CraigsList cheap.
You can take them apart and they are no where near as cumbersome
as an engine crane.

--Doozer

Davek0974
01-29-2010, 09:53 AM
http://www.phc-online.com/v/vspfiles/photos/Hoyer_C-HLA-2.jpg

Hoyer Lifts for hospital patients lift 400lbs and leg spread is adjustable.
Perfect for moving vises and RT's. Can find them on CraigsList cheap.
You can take them apart and they are no where near as cumbersome
as an engine crane.

--Doozer

No floor space, must be overhead.

Dawai
01-29-2010, 11:10 AM
http://www.tractorsupply.com/home-improvement/hardware/door-hardware/rails-hangers/12-ft-plain-box-rail-450-pound-capacity-with-24-in-oc-brackets-galvanized-3551872

Here's a 12 foot piece.. basically a open channel track.

A light gantry that rolls around could be made by backing up the topside with some structural tube or angle.

The 3x4 angle I have welded to a piece hangs on three chains from the ceiling over the garage bay.

THE rollers, them hurt..

Frank Ford
01-29-2010, 11:32 AM
I, too, have no floor space for much of anything, and I wanted a hoist that could help me with the lathe tailstock as well as the mill. So I built a really simple overhead rail system using common water pipe. I've heard some negative criticism about its overall strength, but since I'll never use it for anything heavier than my mill accessories, and I climbed on it with Kurt for a quick test, I simply don't worry about that.

The heart of the system is a simple differential chain hoist I made to use with (oh, no!) non-lifting grade twisted steel chain. It's rated at many times the load I give it, so I guess I'll live.

http://www.frets.com/HomeShopTech/Projects/MiniHoist/minihoist19.jpg

Eleven spokes to catch the chain links on one pulley, ten on the other, smaller diameter one:

http://www.frets.com/HomeShopTech/Projects/MiniHoist/minihoist11.jpg

The mechanical advantage and friction of the chain on the spokes is great enough that loads lift and stay in position. If I'm working on the lathe with the tailstock off, I'll typically leave it hanging over to the right for days at a time to save looking for that illusive flat spot to put it down.

Here's more on that project: http://www.frets.com/HomeShopTech/Projects/MiniHoist/minihoist.html

camdigger
01-29-2010, 12:39 PM
Neat job Frank!

Does anyone know if the differential hoists are still available? All I come up with in searches is the gear type chain falls.

There's two differential chain hoists in the family, but both are older than I am:eek: The sheaves appear to be as cast, cored to fit the outside of the chain. The chains look the same as 1/4" and 5/16" logging/transport chain.

The heavier one works flawlessly, but the lighter one has jamming issues on the lower sheave.

ulav8r
01-29-2010, 01:51 PM
This (http://www.homemetalshopclub.org/projects/crane/crane.html) the one you were thinking of?

That's the one.

Davek0974
01-29-2010, 02:49 PM
Some nice ideas there, thanks.

Time for some thought and trials i think.

Dave

The Artful Bodger
01-29-2010, 02:50 PM
Dave, sorry for the delay I had to my sleep time! Whatever rail system you use if the moving cross beam has any appreciable length I would recommend the cat's cradle as it reduces any tendency for the cross beam to 'crab'.

If you really want to get fancy you could fit a crank or even a electric drive to one of the pullies and get powered operation!

Davek0974
01-29-2010, 04:42 PM
All points noted, time to get physical :D

I'll update when its done.

Dave

whitis
01-29-2010, 05:51 PM
Superstrut/Unistrut/Kindorf with the Superstrut TR294 (1000lbs, $75) or TR292 (500lbs, $40) trolleys:
http://tnblnx3.tnb.com/emAlbum/albums//us_resource/gm102_d_lr_ss1.pdf
Safety factor of 5.
unitstrut versions:
http://store.eberliron.com/products/unistrut_parts/unistrut_trolley_assemblies
http://www.unistrut.com/DB/PDF1/Trolley_Broc.pdf
You can build your own if you prefer.

Check for clearance of the mounting bolts for the struts and the wheels. You might need a slightly deeper strut (E series) or hanger brackets. Last time I bought the standard cross section (A series, 1-5/8" square) struts they were about $16 per 10 foot length. The struts and some of the accessories are available at Lowes, Grainger, and electrical supply houses. Superstrut/Kindorf/Unistrut are more or less interchangable. One nice thing about the struts is you can support them over their full length, minimizing beam span issues and providing redundancy of support.

Here is someones low tech version of an engine hoist without proper trolleys:
http://yotatech.com/f106/dyi-engine-hoist-87545/
Actually pretty strong, at least until you wear through thin metal enough to weaken it. An oversized T-nut or flat plate inserted into the channel would be better.

Even without trolleys and hoist, struts mounted on the ceiling provide stationary attachment points.

Davek0974
01-30-2010, 11:08 AM
Well, the first trial worked so well i think i'l leave it as it is for a while - other things to make and do;)

She ain't pretty but it works realy well, due to the fact that it will only be moved from one end, there is little sign of any crabbing or twisting, its guided on one end and the other just runs on two ball bearings.

http://xa.yimg.com/kq/groups/17605961/sn/799433132/name/DSCN1372.jpg

http://xa.yimg.com/kq/groups/17605961/sn/217952718/name/DSCN1371.jpg

It makes light work of shifting the rotary or vise, with a shelf at the rear i could park them there when not in use, i'll add that later.

Thanks for all the info.

Too_Many_Tools
01-30-2010, 04:02 PM
http://www.phc-online.com/v/vspfiles/photos/Hoyer_C-HLA-2.jpg

Hoyer Lifts for hospital patients lift 400lbs and leg spread is adjustable.
Perfect for moving vises and RT's. Can find them on CraigsList cheap.
You can take them apart and they are no where near as cumbersome
as an engine crane.

--Doozer

The Hoyer lifts I have seen separate at the base leaving the vertical post/lifting arm a separate piece...just right to be inserted into base mounted on a lathe or mill.

Very handy.

TMT