Your father is right the garage door tracks are not heavy enough to support the load you specified. Use the flanges on the c-channel for support.

 

1. You have resources available in house for this project. The most important one is the physics instructor. Question him or her about the effects of leverage and load center of gravity as applied to your guide wheels and other topics. Listen to your father.

2. Hot rolled channel has tapered legs. Any wheels running on the inside of the legs will need a matching taper. Brake bent C-sections made from plate are flat but don't have quite as much material in the corners and strength in that area is somewhat reduced compared to channel.

3. Rectangular structural tube is a viable alternative to C-section posts, as are steel caster wheels a superior alternative to garage door rollers, given the correct size as determined from discussion with the physics instructor.

4. The strength of the rear axle is questionable for this project. Most light GTs have rear axles with a maximum static load rating of 750 lb +/-. A 500 lb payload is going to apply over 800 lb to the rear axle all by itself, and that doesn't include the weight of the forklift, or the weight of the tractor that normally sits on the axle.

5. The other end will require counter weight commensurate with anticipated payloads in order to maintain steering ability, probably something on the order of 200 lb or more.

As a learning exercise for students, this is an excellent project and you should continue with it in spite of the above listed limitations. Bear those limitations in mind and expect that it will fail at some point and deal with the failures as a continuation of the learning process with emphasis on safety.

This project also offers the opportunity to emphasize the laws of physics and their application in the real world and the importance of doing the math (geometry, levers, etc.) to get it right the first time.

The fun part, welding, is only a small portion of the process for building any lifting device.

 

Thank you for your response.

1. I always listen to my father. He is always the first person I call for advice. However, I like to fact check things for myself. I had already calculated the load on the rollers. With 42" forks and a 500lb load on the end of them, my calculations show there would be 1312.5lbs split between the 2 top rollers (656.25 lbs a piece). In a perfect world the middle sets of rollers would have no load torque from the lift on them and just prevent racking. The lower rollers would have torque applied in the opposite direction of the top rollers, but it would be less. I looked through my physics book for the formula to calculate that load but no luck. ( I think I will ask the physics teacher though) I know that I would not be any more than the top rollers and if anything the loads should equal themselves.

2. The standard hot rolled channel is all that I would be able to afford for this, plus like you said the strength is greater. the legs being tapered is what led me to the idea of putting the guide rollers in the door track to prevent them from wanting to walk the taper and bind the lift plate.

3. I would think that stamped steel garage rollers with good bearings would be very similar to the casters. The benefit in my mind is that with the axle shaft pressed in, the face opposite the axle shaft has no protrusions from the wheel and would be better sliding up and down in an enclosed area as opposed to a wheel or caster that has the head of a bolt protruding.

4. You are absolutely right, I am a little worried about the rear axle myself. That’s why I put 500lbs as being the absolute max of what it will lift. What we really need it for is for lifting motors and transmissions and the like onto the work tables and onto pallet racking for storage. I foresee this being a lift and only move far enough to set it down kind of forklift. Not driving across the parking lot with 500lbs on the forks. Plus.... the kids think it is cool as heck that we are taking old junk and making a forklift out of it. Even if it fails it is worth trying for that alone.

5. We went ahead and put a place in the frame work for the hundred lb weight knowing that it would at least need that much. I will weigh it and figure out how much it truly has to have once it is finished.

I appreciate you taking the time to look at this and provide me with feedback. To be honest, you had fewer reservations about its potential than I did when we started talking about it. I always tell my students that failure is always a potential outcome, but quitting should not be.

That being said..... I still think that good garage door rollers would be a simple and economical solution to guide rollers (not saying I am right in that thought)...... However like DonF said, maybe I need to look at the track a little closer.

 

500 lbs made the rear real light....

 

If you're dead set on using garage door rollers, at least get commercial rated rollers that are 3" instead of 2" or smaller; there's a huge difference. If you went with the 3" setup, you could likely use the track that goes with it since it is pretty tough stuff (especially considering you're spreading the load and also reinforcing the track and tying it together to prevent twisting).

It's too bad you aren't closer; I'd be willing to donate some of that stuff that's just laying around.

Also, I agree with your trial and error approach unless it's something (like this project) that could seriously hurt people if it fails; build it right the first time so everybody can go home in one piece. :fing32:

 

This is my custom fabrication hilow ,,,sounds better than homebuilt,,,. I used C shaped channel like you described ,,the carriage that goes up and down has 4 plastic wheels 3" in diameter,that came off a rolling toolbox,attached with grade 8 , 3/8" bolts . the mast is 6 foot 6 inches tall, There is 100 lbs of counter weight on the other end of the tractor. the hilow forks are 29" long. I used a 2000 lb winch to lift the carriage, with a pulley at the top of the mast. It will go up 52" with the winch ,which is enough to load my trailer or truck. Hydraullics would lift much high ,the winch was $100,,hydraulics would have been $1000 plus. It will lift 400lbs ,,more than that the steering wheels lift off the ground. There is a steel mesh between the driver and the cable, also a steel mesh on the roof of the hilow, in case of cable breaking. I am not an engineer. I like to build things and lean towards making things stronger than needed, have been using my hilow 2 years.

 

When I did a search on MTF for "forklift" your hilow never came up. Yours looks exactly like what I am trying to accomplish. I hope ours comes out half that good. But being about 20 miles from the CAT plant, ours has to be CAT yellow..... With running the wheels in the c channel, have you experienced it binding with an uneven load? What I mean is, if one fork is loaded heavier than the other with the carriage rack in the channels and stick? Thats what I thought the garage door track and rollers would help prevent. I worked for a crane yard through highschool and college and we had an old forklift there that if you loaded the forks uneven you could lift it up, but they wouldn't come back down. I remember one time we had it about two thirds up placing a large sheave from a dragline on some pallet racking and we couldnt set it down. We tried backing out but we couldnt get under the rafters so we ended up having to climb the mast and cut the banding and roll the sheave off onto the floor which was luckily rock. Then it took a lot of jumping and pounding with a sledge hammer to get it freed up again...... but i digress.

I like to overbuild my projects as well. We have welded 2x6 rectanglar tubing (from a thrown out commercial treadmill) to the frame of the tractor to spread the load over the axles. Also the floor where your feet go (you can see the plywood template in the pictures) is actually a solid sheet of 1/4 steel that is bolted through the tractors original frame and the added rectangular tubing to strengthen the entire rear of the lift. I don't want to give anyone the impression that just because we are using "junk" to build it that it isn't going to be safe or worth using. With all the gussets and bracing that have gone in, and that are cut and ready to be welded in, we might be over the rear axles limit before we ever pick anything up. In which case we will find another solution and press on.

 

Good projects.
Check out this thread over on machine builders. They've got something similar going. Maybe swap ideas,
http://kramerville.net/ubb/ubbthreads.php?ubb=showflat&Number=10657&page=1

 

Yes it has bound up with an uneven load,,, I use it mostly for moving scrap metal,and junk appliances...so hooking a chain to the load and backing up ,and letting the load fall on the ground is not a problem.

 

have you thought about adding side rollers to keep the carriage centered? I came to this site because I'm getting ready to build one myself and there was a post on MBN on my topic to check it out. did you just re locate your controls or did you modify the transmission too.

 

I hadn't thought about adding rollers to keep it centered, but now that you mention it, I feel foolish for not... I will definitely look into it. The controls had been removed when I got the tractor, and we are in the process of reversing the steering right now. The tractor is hydrostat so it should run the same either direction. We are just going to add a simple forward reverse hand lever connected to the transaxle with some way to lock it in neutral.

Banjojelly, do you have machine shop facilities available? Rollers for your application need be no more than 2" diameter round stock tapered to match the channel and counter-bored for the head of a 5/8" bolt used for an axle. No bearing is necessary for such a low speed, minimal movement application.

With the Cat plant so near, have you considered speaking to their community affairs personel for some assistance with this project? What they consider scrap would be prime steel for your purposes. Possibly some brochures showing Cat forklifts may be available to enhance the learning process.



That is a wise policy to follow. :fing32:

I do have an ancient lathe that I do know how to use (I don't let the kids use it though, insurance killed that years ago) And If I purchased some round stock I could make what you are saying without too much fuss.

I can't say enough good things about CAT as a company and how they treat the people in our area. Lots of my kids parents work for CAT and I have a pretty good record of kids getting hired to work there straight out of high school. I have asked about scrap metal before, but everyone in a 60 mile radius around them begs from them so I think they just tend to say no, which I understand. (They do donate money to schools and let us tour for free) I hate asking for handouts anyway. I get most of my metal trading with scrappers.

If anyone ever gets a chance to tour their facility, I would highly recommend it. Great tour. I take students twice a year on average and they have to drag me out like a little kid from a toy store.

 

Banjojelly, do you have machine shop facilities available? Rollers for your application need be no more than 2" diameter round stock tapered to match the channel and counter-bored for the head of a 5/8" bolt used for an axle. No bearing is necessary for such a low speed, minimal movement application.

With the Cat plant so near, have you considered speaking to their community affairs personel for some assistance with this project? What they consider scrap would be prime steel for your purposes. Possibly some brochures showing Cat forklifts may be available to enhance the learning process.

However, I like to fact check things for myself.

That is a wise policy to follow. :fing32:

 

This is what I use. I have no binding problems.

http://www.ebay.com/itm/2pcs-KR16-K...r-Needle-Roller-Bearing-/390413623568?pt=LH_DefaultDomain_0&hash=item5ae6772110

 

The rollers that Kbeitz posted are availible in a tappered version, and a tappered flanged version. I belive those are what are used on commercial forktruck masts. They are usually called cam followers and are common in industrial applications. Our garbage trucks at work use several different styles of them.

 

If you designed the carriage so it wrapped around the outside of the channel and had the rollers on the outside of the channel, no taper would be needed, may also be easier to take apart for repairs/modifications.

Harold

 

As for the cam followers, can any of you post pics showing how they are used in your track roller systems?

I think I understand how they work, but still not sure how they would eliminate binding, as the outside of the roller is flat and could push against the inside of the track... See the suggestion above.

Any thoughts on round steel cylinders for the carriage to slide up and down? My thought would be to make sure to keep it greased up slicker than hog snot. Cylinders are equally strong in any direction. That's a polite way of saying that they are equally weak in all directions. A 4" pipe is 4.5" outside diameter with a 0.237" wall and weighs 10.79 lb per foot. A 4" channel has a depth of 4.0" with a web thickness of 0.187" and a weight of 5.4 lb per foot. Two opposing channels are stronger in the required direction than one pipe and weigh the same in total.

Another thought that occurs; I've heard many use the term "winch" when referring to implements that lift.

It's my understanding that winches are designed to pull along a flat horizontal surface, while a "Hoist" is used for lifting.

Is this why some of you add pulleys, so that the winch can pull horizontally as they are designed to?

A winch is a device used to pull a load. The direction is irrelevant. A hoist is a winch which pulls in a generally vertical direction, but is nonetheless still a winch. Tow trucks use winches to hoist the front (or rear as need be) ends of cars for transport.

It all depends on how you look at it. 'To winch' is a verb that generally refers to a somewhat horizontal pull. 'To hoist' is a verb that generally refers to a somewhat vertical pull. The key word in both definitions is 'pull', and that takes a winch.

 

Ah I like this.

 

OK..... Hydrostatic is the ticket for that. The old Jacobsen I used to build my mini backhoe is Hydrostatic.

unfortunately the statesman that i plan on using for this project is not.

 

Glad to have come across this thread. I have gotten some useful ideas, and would like to see some more of your results, projects.

To the OP, How did it turn out?

If it turned out being a bit too ambitious and you still have the need for lifting engine blocks and what not, you might try a hand lift truck, like this one.
http://www.zoro.com/g/00082023/k-G3...m_medium=cpc&utm_campaign=Google_Shopping_Feed&gclid=CL2Y7crgyr8CFaFAMgodvhgALg

They start around $500, but this could also be a good project for your class- to make one yourselves, or even upgrade this one with a winch or hoist implement.

As for the cam followers, can any of you post pics showing how they are used in your track roller systems?

I think I understand how they work, but still not sure how they would eliminate binding, as the outside of the roller is flat and could push against the inside of the track...

Any thoughts on round steel cylinders for the carriage to slide up and down? My thought would be to make sure to keep it greased up slicker than hog snot.

Another thought that occurs; I've heard many use the term "winch" when referring to implements that lift.

It's my understanding that winches are designed to pull along a flat horizontal surface, while a "Hoist" is used for lifting.

Is this why some of you add pulleys, so that the winch can pull horizontally as they are designed to?

 

Glad to have come across this thread. I have gotten some useful ideas, and would like to see some more of your results, projects.

To the OP, How did it turn out?

Here is a thread of how far we progressed on the forklift last school year.
http://www.mytractorforum.com/showthread.php?t=324082&highlight=
Unfortunately nothing progressed on it this previous school year. My wife and I currently live about three and a half hours from where we grew up in Southern Illinois and I was given the opportunity to teach at a school about 15 mins from there so we are in the middle of a move and trying to get our house ready to sell. I have put the forklift in storage until I have time to take it to my new school and work on it. I am still planning on using a winch to provide the lift and am confident that it will work well for my application.

 

I'll be glad to answer your additional questions, but you should start your own thread with them. This one is almost a year and a half since the OP posted on it and I can see that your questions will have the topic drift away from the OP's original information request.

 

Good call. Thanks again Bob.

 

WEll.... took years to get the lead out of my butt... here it is. :tango_face_grin:

 

 

Very neat Jim! Glad to see this thread back up!
Looks like you used a Suburban for your forklift? Did you flip the transmission to have the 3 forward gears going the correct way?

Sent from my SM-A520W using Tapatalk

 

Old sears roper. Built a jack-shaft so I could reverse the engine output rotation. Still have 3 fwd gears with hi/low so technically 6 fwd & 2 revers speeds. I used a marine hydraulic helm for the steering and the steering cylinder I got on ebay from a JD 2500A.

 

With this attachment I'm able to move my trailers around with ease

 

I try to pop in here frequently BUT am rather busy Trying to get the new Machine builders network up and running smoothly. Myself and two others have started a new site as the old one is no longer being maintained due to the owner passing. After a year of trying to get control of it we gave up and just built a new one. ALL are welcome there. come join us and share ideas. :comp26::tango_face_grin:

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