Have just the same question!
carl425The wheelbase of the trucks I used was about 3/4". The trucks were also rigid. The most extreme case I tested was a 1/4" gap in the left rail followed by a 1/4" gap in the right rail. I was amazed that the cars rolled right across without complaining.
Wow! 1/4" is way more than I would have expected, and I hope way more than I can achieve with some careful engineering. By including some sort of homing guides or stop blocks at the ends of travel I was expecting to be able to get within 1mm (or whatever that is in inches). I also suspect that vertical and horizontal misalignment will be more of an issue than a straight gap.
Bob
FowlmereRRAs a matter of interest, how much mis-alignment or gap between the fixed and moving rail ends did you find was workable?
The most interesting thing I learned was that a diagonal cut across the track worked better than a cut straight across. As long as the gaps were staggered so that only one wheel was off the rail at a time, the cars would roll across without a problem.
The wheelbase of the trucks I used was about 3/4". The trucks were also rigid. The most extreme case I tested was a 1/4" gap in the left rail followed by a 1/4" gap in the right rail. I was amazed that the cars rolled right across without complaining.
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
Hi Carl - As a matter of interest, how much mis-alignment or gap between the fixed and moving rail ends did you find was workable? I am currently designing an elevator to get between levels in my planned double-decker, and am also trying to figure out the required precision.
btw - my elevator is taking the place of an over-ambitious grade with passing siding, so i have elected to go for a two-track design, one moving in the opposite direction of the other, which will simulate the meet-and-wait operation quite nicely. It also has the side effect of being inherently balanced, so I am planning to do the movement by means of a toothed "timing belt" and pulleys. It looks good so far, but I am unsure about the accurate location at the top and bottom of travel.
Sounds like you're off to a good start, Carl.
Good Luck, Ed
gmpullmanI have a ball-screw you can have if you can use it.
Thanks for the very generous offer Ed.
I decided to press on with my swing gate. After some experimentation I determined that I was drastically overestimating the precision required for the tracks where they cross the gap.
I installed the first track on the gate yesterday and found it works much better than I had feared. I did have a few derailments in testing until I figured out a burr left behind from where I cut the rail was the problem.
Only problem now is figuring out how to spend the $350 I "saved".
carl425My total now is at $350, but more than half of that is the ball screw that I'd like to use to run the shelves up and down.
Carl,
I have a ball-screw you can have if you can use it. I took it off a piece of equipment several years ago thinking it would be handy "someday".
I wasn't sure if it was still where I had left it but I found it today.
It is 42" overall, the travel is roughly 36 or 37" the worm is .614 OD and there are bearings pressed on each end but no pillow blocks. The bearing ID is .393 +-
I'm sure the capacity is plenty to lift at least 100 lbs. or so. There's some slight corrosion on it but the ball nut runs smoothly.
There was a linear bearing attached to it but—unfortunately— part of that is missing. As is the manufacturer's ID.
PM me and I can see how much UPS would be to send it to you if you're interested.
*edit* I can post photos later if you'd like.
[edit #2]
Do you have an air supply? I have another possibility:
A Tolomatic linear band cylinder. Brand new!
http://www.tolomatic.com/products/product-details/mxp-s-long-stroke-pneumatic-air-cylinder#/
The model I have is MXP40S and the usable travel is 30". It has cushion ends. You would need to regulate the air controls so it lifts slowly but these things are easily controlled. Would cost slightly more to ship but it's yours if you can use it.
Also...
something like these might be handy?
http://www.ebay.com/itm/A-set-of-Linear-rails-27-x-5-8-Shaft-w-Block-Bearing-Linear-2-/121918826328?hash=item1c62eda758:g:Iv0AAOSwAuNW4D4U
You could get longer pieces of 5/8 cold rolled or ground & polished shaft if you needed longer run.
Regards, Ed
This guy offers hardware, and I inquired a while back about such a set-up discussed in this thead, and he said it could be done with his hardware either on my own or of his design. Mine would be colapsable as am limited on height above the top level of my double-deck.
http://www.engineeredlayoutsystems.com/
Victor A. Baird
Fort Wayne, Indiana
7j43kIt's hard to believe that that is the biggest challenge.
The biggest challenge will be clicking "buy now" in my Amazon shopping cart. My total now is at $350, but more than half of that is the ball screw that I'd like to use to run the shelves up and down. I may get cheap and do a cable & pulley thing instead. I'm still procrastinating.
I'm not worried about droop for two reasons. First, this is going in the corner of the room and the shelves will be L-shaped with one guide rail on each leg of the L. This will allow me to position the bearing blocks so that the shelf will be somewhat balanced rather than having all the weight cantilevered. Second is that the only time the weight of the shelf will be on the bearings is when it's lifted out of the way. For operation, the shelf will be sitting on ledges attached to the stationary benchwork.
Like this:
HObbyguy The biggest challenge may be how to attach your shelves to the slides without them drooping.
It's hard to believe that that is the biggest challenge. A second set of bearings under the first, connected vertically with the first, while also connecting the second and the outer edge of the platform will negate the drooping. Assuming, of course, that the builder designs appropriately.
When completed, it should be a very beautiful solution.
Ed
carl425 This is clearly not the most economical solution, but an interesting design that will be fun to build (and show off) helps me with the motivation to get the work done.
This is clearly not the most economical solution, but an interesting design that will be fun to build (and show off) helps me with the motivation to get the work done.
Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger... doing it my way. Now working on phase 3. - Walt
For photos and more: http://www.wkhobbies.com/model-railroad/
The only time you need precision alignment is when the pieces are at or near their resting position on the layout. And for that, guide pins will suffice.
HObbyguyIf I was building a lifting section and money wasn't a big concern that's what I would go with. The only consideration is that since they are so precise and strong they must be mounted perfectly parallel to each other.
Thanks Walt. I knew somebody here would have experience with them.
I have 4 narrow shelves that cross the door - two sceniced levels and upper/lower staging. My plan is to attach the shelves to the bearings and have them come down onto ledges on the sides that will support them for operation. I'll power lift only the bottom shelf and let them stack on top of each other as they go up. Each shelf will be a couple inches narrower than the one above it to allow clearance.
I've been thinking about the "perfectly parallel" issue as well. My plan is to attach the rails at the top only to start. Build and attach one shelf at the top, then slide it to the bottom and attach the rest of the rail to the wall.
carl425Steven S If you don't mind splurging, linear guide rails like the ones below will give you good alignment with little or no play. They're often used in CNC machines. This stuff looks pretty cool. Can it be mounted vertically and support a shelf of layout cantilevered off of it?
This stuff looks pretty cool. Can it be mounted vertically and support a shelf of layout cantilevered off of it?
Linear bearings like those are used very widely in industry for all sorts of automation and I designed machines that used them in the distant past. They are accurate to within a few thousands and will hold a ton- no comparison to drawer slides. No problem mounting them vertically and cantilevering a shelf from them. They will hold as much as the fasteners will allow without any measurable give.
If I was building a lifting section and money wasn't a big concern that's what I would go with. The only consideration is that since they are so precise and strong they must be mounted perfectly parallel to each other.
There was an article 2 months ago (Feb or March MRR issues) that explained everything about using drawer glides. I did it that way too and it worked out nicely. BUT, I suggest the roller bearing type of drawer slides. The cheap ones work fine but they have a little wobble. Now I did have to remove the wobble with a hammer and drill. There is about a 1/2" play so when I lower it and get down to the layout level I have to hold it and ease it doen onto the pind.
jfb this is just another idea that i am using thrown out there for thought purposes for pondering. I have 4 file cabinet slides mounted to wall studs properly positioned and 4 long l brackets bolted to the board and i am using folding 2x4,s as the legs, properly latched and the right height it was a under 40 dollar endeavor. I am very happy with outcome and it saves a lot of space to walk under.
this is just another idea that i am using thrown out there for thought purposes for pondering. I have 4 file cabinet slides mounted to wall studs properly positioned and 4 long l brackets bolted to the board and i am using folding 2x4,s as the legs, properly latched and the right height it was a under 40 dollar endeavor. I am very happy with outcome and it saves a lot of space to walk under.
This sounds like what I was going to suggest - drawer slides, mounted vertically. These are hardware store items, very reasonably priced. If you use one at each corner of the lift-up section (not cantilevered) it should provide good alignment.
I saw the Mianne model at the Springfield show in January. It was very impressive. It was solid and its motion was smooth and even. As I recall, it had a similar drawer-slide mount, and was driven by a cable-and-pulley system and an electric motor. This is their video:
And here is a video made my a modeler for his own layout:
It takes an iron man to play with a toy iron horse.
Steven SIf you don't mind splurging, linear guide rails like the ones below will give you good alignment with little or no play. They're often used in CNC machines.
Try looking at television lifts for cabinetmakers.
http://www.azwoodman.com/flat-screen-tv-lifts.html
This way you get all the motors, controls, etc.
Do a Google search for :
TV Lift System > images
If you don't mind splurging, linear guide rails like the ones below will give you good alignment with little or no play. They're often used in CNC machines.
Round...
http://g02.a.alicdn.com/kf/HTB1edpNIXXXXXbnXFXXq6xXFXXXT/New-SBR16-rail-L580mm-16mm-linear-round-guide-cnc-router-part-linear-rails-for-SBR16UU.jpg
or flat....
http://www.aliexpress.com/item-img/cnc-ball-type-linear-guide-rail/642499118.html#
It's way bigger than HO scale, but the basic idea of using a screw-post at each corner, driven by a common chain around a gear at the bottom of each corner by a single drive motor is a good one.
The design is adapatable, as I've seen similar mechanisms in use for other purposes. It will scale down well. Parts should be available to make it work. Common limit switches should allow precise repetition of accurate matching between rails. Final tuning and maintenance should be minimal.
Mike Lehman
Urbana, IL
This company has a powered lift gate:
http://www.miannebenchwork.com/miannecatalog.pdf
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
The Pullman Co. makes a window sash spring that can be mounted above or on the side. Other than that...springs.
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What do you use for hardware to support vertically moving layout sections? I'm interested in building a powered lift up gate and need the vertical tracks that would attach to the wall and the widgets that would ride in the tracks and attach to the layout sections.