jon f mn
Well-known Member
My daughter asked me for a trailer, which I was happy to do. I've been planning on building one for each of my kids anyway, so since she asked she gets to be first. I decided on a 4' x 8' 2,000 lb size with a dump for her. I wanted a reliable and idiot proof design and thought a sissor lift with a hand cable winch and a series of pulleys might work. I was worried that the lift force at the start of the lift might be marginal, and it turns out I was right. But that's for later. Here is the build as it's gone so far. I busted my phone towards the end of the first day, so the pics start at the end of the main frame build. The trailer is all aluminum and the main rails are 3" channel. They are 10'6" long, giving a 4' tongue and 6'6" to the pivot leaving an 18" over hang.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23087.png"/>
The crossmember at the frame bend is 2 1/2 x 3/16" square tube. I really created a challenge here because this is a critical piece anyway. When ever a beam makes a bend it needs to be tied well to keep it from flexing at the bend. Then I put the bends in the beam which have to be done in such a way that they maintain the integrity of the beam. That's why I chose tube for this part. And if that wasn't enough, this one also has to bear the weight when the box is dumped. So it has to be both rigid and strong. I beveled the joints good and ran 2 passes with the tig welder on these to make sure they were good. I also plated the bottom of the bend and added the gussets to both sides on the top to make sure the tie to the main rails was good emough and that the mains were plated at the bend.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23089.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23090.png"/>
There is also a good crossmember at the axle, this is also a critical point in the frame because the frame needs to be held upright and parallel and there are a lot of forces applied to this area from a lot of different directions. There is also a member at the rear to hold the beams at the pivots. The pivots are made from 1 1/4 x 1/8" square tube and the pins will be 1" steel shaft. This makes a good hinge and with the square tube thereis no way for the pin to seize.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23091.png"/>
Next was to build the box. The box is made from .100 diamond plate. I cut a 4 x 8' sheet into 3-16"x8' pieces and bent a 3" lip in on the bottom and a 2" out and 1" down on top. I've used this pattern on many trailers and it's very strong, yet light weight. The box is actually 50"x98" since I always over size the standard sizes such as 4x8, 5x8, 5x10. This is so if you want to haul a piece of sheet like ply wood or steel they don't get wedged in the trailer. Getting a sheet of plywood or sheetrock out of a trailer that is actually 4x8' can be a challenge. So I plasma cut the front to 50".
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23093.png"/>
When that was tacked in the rear tube was next. I usually use 2x4x1/8 tube for this because it gives a good place for lights so there is no need for extra light boxes.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23094.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23095.png"/>
I cap the uprights, but leave the bottom open so they don't hold water. This is an important part of this type trailer because you need to hold the sides upright and the rear crossmember is the only one that has to carry the entire load when loading. Once the load crosses the rear member the load is shared by the members in front and behind.
The next thing was the fenders. I always put a crossmember at the front and rear of the fenders to help hold the fenders on, but also because it makes the fenders a structural part of the box by helping keep the sides of the box from bending. This is especially good when folks strap loads by hooking to the box lip.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23096.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23097.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23098.png"/>
Next was the box pivot. I used a piece of 1/4" plate and welded some of the 1 1/4 square tube to it. It is welded to both the box and the fender crossmember so the force goes through bot the box side and fender, thereby spreading the force over a very large area.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23099.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23100.png"/>
Next was the lift. I wanted to get a 45° angle of dump, to achieve that I needed 60" of lift. So the sissor arms are 30" long from 1 1/2x1/8" square tube. I v'd the ends and welded in a 2" long piece of the 1 1/4" tube for the pivots. I felt that would work because for these all the force is compression.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23101.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23102.png"/>
The center pieces were the same tube with a piece of 1/4" plate welded on to attatch the pulleys.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23103.png"/>
This is what it looks like together. There are 3 pulleys and the winch is 1,000 lb capacity.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23104.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23105.png"/>
What I wanted was about 1,000 lbs of lift at the front. This setup gives about 200 lbs max. I could shorten the tubes a couple inches and lower the fron crossmember another 2 or 2 1/2" and I think it would be close. Once the box is up just a few inches there is plenty of lift, just not at the start. The problem with making the changes is that there will be a corresponding lost oftilt angle. I calculate it at a bit less than 30° which I think is not enough. I may change it over to hydraulic as I can get a hand pump and cylinder I think will do the job forbabout $200.00. We'll see since I have a couple weeks to contemplate on it.
Well that's it so far. Hope you enjoyed the post.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23087.png"/>
The crossmember at the frame bend is 2 1/2 x 3/16" square tube. I really created a challenge here because this is a critical piece anyway. When ever a beam makes a bend it needs to be tied well to keep it from flexing at the bend. Then I put the bends in the beam which have to be done in such a way that they maintain the integrity of the beam. That's why I chose tube for this part. And if that wasn't enough, this one also has to bear the weight when the box is dumped. So it has to be both rigid and strong. I beveled the joints good and ran 2 passes with the tig welder on these to make sure they were good. I also plated the bottom of the bend and added the gussets to both sides on the top to make sure the tie to the main rails was good emough and that the mains were plated at the bend.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23089.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23090.png"/>
There is also a good crossmember at the axle, this is also a critical point in the frame because the frame needs to be held upright and parallel and there are a lot of forces applied to this area from a lot of different directions. There is also a member at the rear to hold the beams at the pivots. The pivots are made from 1 1/4 x 1/8" square tube and the pins will be 1" steel shaft. This makes a good hinge and with the square tube thereis no way for the pin to seize.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23091.png"/>
Next was to build the box. The box is made from .100 diamond plate. I cut a 4 x 8' sheet into 3-16"x8' pieces and bent a 3" lip in on the bottom and a 2" out and 1" down on top. I've used this pattern on many trailers and it's very strong, yet light weight. The box is actually 50"x98" since I always over size the standard sizes such as 4x8, 5x8, 5x10. This is so if you want to haul a piece of sheet like ply wood or steel they don't get wedged in the trailer. Getting a sheet of plywood or sheetrock out of a trailer that is actually 4x8' can be a challenge. So I plasma cut the front to 50".
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23093.png"/>
When that was tacked in the rear tube was next. I usually use 2x4x1/8 tube for this because it gives a good place for lights so there is no need for extra light boxes.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23094.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23095.png"/>
I cap the uprights, but leave the bottom open so they don't hold water. This is an important part of this type trailer because you need to hold the sides upright and the rear crossmember is the only one that has to carry the entire load when loading. Once the load crosses the rear member the load is shared by the members in front and behind.
The next thing was the fenders. I always put a crossmember at the front and rear of the fenders to help hold the fenders on, but also because it makes the fenders a structural part of the box by helping keep the sides of the box from bending. This is especially good when folks strap loads by hooking to the box lip.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23096.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23097.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23098.png"/>
Next was the box pivot. I used a piece of 1/4" plate and welded some of the 1 1/4 square tube to it. It is welded to both the box and the fender crossmember so the force goes through bot the box side and fender, thereby spreading the force over a very large area.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23099.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23100.png"/>
Next was the lift. I wanted to get a 45° angle of dump, to achieve that I needed 60" of lift. So the sissor arms are 30" long from 1 1/2x1/8" square tube. I v'd the ends and welded in a 2" long piece of the 1 1/4" tube for the pivots. I felt that would work because for these all the force is compression.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23101.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23102.png"/>
The center pieces were the same tube with a piece of 1/4" plate welded on to attatch the pulleys.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23103.png"/>
This is what it looks like together. There are 3 pulleys and the winch is 1,000 lb capacity.
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23104.png"/>
<image src="http://forums.yesterdaystractors.com/photos/mvphoto23105.png"/>
What I wanted was about 1,000 lbs of lift at the front. This setup gives about 200 lbs max. I could shorten the tubes a couple inches and lower the fron crossmember another 2 or 2 1/2" and I think it would be close. Once the box is up just a few inches there is plenty of lift, just not at the start. The problem with making the changes is that there will be a corresponding lost oftilt angle. I calculate it at a bit less than 30° which I think is not enough. I may change it over to hydraulic as I can get a hand pump and cylinder I think will do the job forbabout $200.00. We'll see since I have a couple weeks to contemplate on it.
Well that's it so far. Hope you enjoyed the post.
