Big Blue's Transformation

[ArdWrknTrk]

Yes!! Fish mouth!

I’m not in Apple’s garden save for on this iPhone. Do they have one for Windows?

An Android app for Windows????

I added a link to an online tube coping calculator to my post above.

Sometimes the back cut angles aren't entirely intuitive.

But you're a lot better off with a good pattern to get started.

You don't have oxy/acetylene to torch out the 1" plate?

If you can export a DWG, you can have those brackets waterjetted quickly and cleanly.

Maybe Brandon knows some shop in T-town.

Online.... quick turnaround is another possibility.

https://onlinewaterjet.com/waterjet-services-capabilities

 

[Gary Lewis]

An Android app for Windows????I added a link to an online tube coping calculator to my post above.Sometimes the back cut angles aren't entirely intuitive.But you're a lot better off with a good pattern to get started.You don't have oxy/acetylene to torch out the 1" plate?If you can export a DWG, you can have those brackets waterjetted quickly and cleanly.Maybe Brandon knows some shop in T-town.Online.... quick turnaround is another possibility.https://onlinewaterjet.com/waterjet-services-capabilities

No, I don't have oxy/acetylene to cut with. But Scott knows a lot of people so surely someone can do that. Or, that water jetting option might be the way to go, and I can easily output the tow eyes as a DWG. Good idea, thanks.

 

As for the link, I'm joining a rectangular tube with round one at right angles so it is pretty easy. But to answer your question, the width of the tubes are 2 1/2", and with a 1/4" wall they are perfect for the 2" OD of the tube that will be inserted.

 

In the view below you can see the two places to be fish mouthed. One is the pivot point in the lower right, and the other is in the top center where the two square tubes hit the round tube to support the spare tire.

 

The pivot point is pretty straightforward, but on the latter I'm thinking I'll have to join the three tubes of the swing arm together and then fish mouth the top two to ensure I have a good joint at that point. But your idea of using a hole saw is a good one, and while not as precise as a fly cutter it should be very good.

 

[ArdWrknTrk]

No, I don't have oxy/acetylene to cut with. But Scott knows a lot of people so surely someone can do that. Or, that water jetting option might be the way to go, and I can easily output the tow eyes as a DWG. Good idea, thanks.

 

As for the link, I'm joining a rectangular tube with round one at right angles so it is pretty easy. But to answer your question, the width of the tubes are 2 1/2", and with a 1/4" wall they are perfect for the 2" OD of the tube that will be inserted.

 

In the view below you can see the two places to be fish mouthed. One is the pivot point in the lower right, and the other is in the top center where the two square tubes hit the round tube to support the spare tire.

 

The pivot point is pretty straightforward, but on the latter I'm thinking I'll have to join the three tubes of the swing arm together and then fish mouth the top two to ensure I have a good joint at that point. But your idea of using a hole saw is a good one, and while not as precise as a fly cutter it should be very good.

 

1/4" wall??This is a tire and jack carrier, right? :nabble_anim_confused:Under 200# it's carrying. Even a 4G drop is only 800 and the truck does have suspension.Triangles are rigid. Compression or tension you could do it with 1/16" wall.You're going to have a bunch of odd shear at the pivot, but I would suggest 11gauge (1/8", .123") and a gusset either side before I would think about hanging an extra 60+# back there.Hole saws are fine for weld prep.And you can get deep well at least 3". It would be money well spent for the time it would save you.

[ArdWrknTrk]

No, I don't have oxy/acetylene to cut with. But Scott knows a lot of people so surely someone can do that. Or, that water jetting option might be the way to go, and I can easily output the tow eyes as a DWG. Good idea, thanks.

 

As for the link, I'm joining a rectangular tube with round one at right angles so it is pretty easy. But to answer your question, the width of the tubes are 2 1/2", and with a 1/4" wall they are perfect for the 2" OD of the tube that will be inserted.

 

In the view below you can see the two places to be fish mouthed. One is the pivot point in the lower right, and the other is in the top center where the two square tubes hit the round tube to support the spare tire.

 

The pivot point is pretty straightforward, but on the latter I'm thinking I'll have to join the three tubes of the swing arm together and then fish mouth the top two to ensure I have a good joint at that point. But your idea of using a hole saw is a good one, and while not as precise as a fly cutter it should be very good.

 

With a square tube for a bumper I'd be more concerned with torsion while the carrier is 90° to its axis.Unless it fits just right for some reason I'd think you would want something like 3 X 5.The pivot pin should go all the way through and be welded to both the top and bottom section.(I'm not seeing that in your isometric picture. But maybe it's my eyes and phone)

[ArdWrknTrk]

No, I don't have oxy/acetylene to cut with. But Scott knows a lot of people so surely someone can do that. Or, that water jetting option might be the way to go, and I can easily output the tow eyes as a DWG. Good idea, thanks.

 

As for the link, I'm joining a rectangular tube with round one at right angles so it is pretty easy. But to answer your question, the width of the tubes are 2 1/2", and with a 1/4" wall they are perfect for the 2" OD of the tube that will be inserted.

 

In the view below you can see the two places to be fish mouthed. One is the pivot point in the lower right, and the other is in the top center where the two square tubes hit the round tube to support the spare tire.

 

The pivot point is pretty straightforward, but on the latter I'm thinking I'll have to join the three tubes of the swing arm together and then fish mouth the top two to ensure I have a good joint at that point. But your idea of using a hole saw is a good one, and while not as precise as a fly cutter it should be very good.

 

I better understand now.I guess I was thrown by the horizontal line passing the upright.I'm used to drawing conventions where there are no breaks in a plane.Yes, adding some depth will increase stiffness, but these are already small triangles.Like I said, you could add a gusset or wrap the pivot post, using a lot less material or weight.***Imagine you made the post taller and made a U shaped strap from the jack carrier tab around the pivot and back.Then the lower horizontal is almost completely in compression and the whole member can be much smaller.

[Gary Lewis]

With a square tube for a bumper I'd be more concerned with torsion while the carrier is 90° to its axis.

Unless it fits just right for some reason I'd think you would want something like 3 X 5.

The pivot pin should go all the way through and be welded to both the top and bottom section.

(I'm not seeing that in your isometric picture. But maybe it's my eyes and phone)

I apologize for the pic, but it is what I have at the moment until I can re-learn playing with TurboCAD in 3D. (I'm missing how to put the work plane where I want it, and when I try to do something it isn't where it is supposed to be.)

Anyway, several things to address, inc thickness of the material of the swing arm, height of the lower arm (from the other thread), and the pivot pin fit into the bumper.

You are right that the thickness of the swing arm doesn't need to be 1/4" since it is triangulated. But, all of the force will be on the bit that attaches to the pivot, so I want that to be stout. How 'bout if I use 1/8" all the way around on the swing arm? That will reduce the weight by 50% and make the welding easier as well - except for the ends of the fish mouths as that material will taper to nothing. Maybe I should cut it back so it is 1/8" thick as well?

As said in the other thread, the lower piece of the swing arm will be 3 1/2" tall. And you can see from the drawing of the RuffStuff pivot that I'm going to use the sleeve is 4" tall, so that let's me take full advantage of the sleeve and weld all around on it.

Also shown is the 6.13" length of the stem of the pivot. That will let me put the stem completely through the 5" bumper and weld it both top and bottom.

But, as I'm looking at this, there's 6.5" from the tip of the stem to the sleeve. I'd better check and see how high I have the pivot above the bumper. I don't want a whole lot of the pivot sticking out below the bumper so I may have to machine it down a bit.

[ArdWrknTrk]

I apologize for the pic, but it is what I have at the moment until I can re-learn playing with TurboCAD in 3D. (I'm missing how to put the work plane where I want it, and when I try to do something it isn't where it is supposed to be.)

Anyway, several things to address, inc thickness of the material of the swing arm, height of the lower arm (from the other thread), and the pivot pin fit into the bumper.

You are right that the thickness of the swing arm doesn't need to be 1/4" since it is triangulated. But, all of the force will be on the bit that attaches to the pivot, so I want that to be stout. How 'bout if I use 1/8" all the way around on the swing arm? That will reduce the weight by 50% and make the welding easier as well - except for the ends of the fish mouths as that material will taper to nothing. Maybe I should cut it back so it is 1/8" thick as well?

As said in the other thread, the lower piece of the swing arm will be 3 1/2" tall. And you can see from the drawing of the RuffStuff pivot that I'm going to use the sleeve is 4" tall, so that let's me take full advantage of the sleeve and weld all around on it.

Also shown is the 6.13" length of the stem of the pivot. That will let me put the stem completely through the 5" bumper and weld it both top and bottom.

But, as I'm looking at this, there's 6.5" from the tip of the stem to the sleeve. I'd better check and see how high I have the pivot above the bumper. I don't want a whole lot of the pivot sticking out below the bumper so I may have to machine it down a bit.

No need to apologize.

Like I already mentioned my equipment is marginal, and my perspective on the world is narrow.

Ignore my edit above.

I didn't realize you were making this fit to off the shelf parts....

You could still gain considerable shear resistance by adding a convex gusset from the top of the pivot sleeve to the jack stop.

 

[Gary Lewis]

I better understand now.

I guess I was thrown by the horizontal line passing the upright.

I'm used to drawing conventions where there are no breaks in a plane.

Yes, adding some depth will increase stiffness, but these are already small triangles.

Like I said, you could add a gusset or wrap the pivot post, using a lot less material or weight.

***Imagine you made the post taller and made a U shaped strap from the jack carrier tab around the pivot and back.

Then the lower horizontal is almost completely in compression and the whole member can be much smaller.

At the risk of typing while you are typing again...

I could change out the lower piece and make it either 3 1/2" or 4" square tubing. That would let me drill through it and then the welds are just to hold it in place on the pivot rather than take the load. But, that would mean that I can't have the stop for when the tire carrier swings 180. Or, if I do have that stop I'll have to move the pivot point inboard some.

I think I'll ask Scott how much weight the current design's welds can take. And, what the odds are of egging the sleeve with our welding as we don't want to cause the bearings to bind.

Another thing to remember is that there will be support on the inboard end of the swing arm. And a clamp. So any time we are going down the road the thing is supposed to be literally bolted down to the bumper. Given that, there shouldn't be a huge load on the welds and the pivot.

[ArdWrknTrk]

At the risk of typing while you are typing again...

I could change out the lower piece and make it either 3 1/2" or 4" square tubing. That would let me drill through it and then the welds are just to hold it in place on the pivot rather than take the load. But, that would mean that I can't have the stop for when the tire carrier swings 180. Or, if I do have that stop I'll have to move the pivot point inboard some.

I think I'll ask Scott how much weight the current design's welds can take. And, what the odds are of egging the sleeve with our welding as we don't want to cause the bearings to bind.

Another thing to remember is that there will be support on the inboard end of the swing arm. And a clamp. So any time we are going down the road the thing is supposed to be literally bolted down to the bumper. Given that, there shouldn't be a huge load on the welds and the pivot.

I understand that. That is why I said what I did about torsion on the bumper when the carrier is swinging open. (@ 90°)

I don't think you need to worry about the weld being a weak point.

Scott can always build it thicker or wider if it concerns him.

 

[Gary Lewis]

I understand that. That is why I said what I did about torsion on the bumper when the carrier is swinging open. (@ 90°)I don't think you need to worry about the weld being a weak point.Scott can always build it thicker or wider if it concerns him.

Ok, I think we are together on this. The plan could be changed to beef up the joint, but the way it is designed should easily be strong enough. And if I start changing anything there's a ripple effect that I might not catch until the last minute, so I think I'll stay with what I have - at least until Scott reviews it.

 

One thing that isn't in the materials list but should be is strap with which to close the ends of the bumper. (At what point in size does "strap" become "plate"?) I'll need a foot of 4" wide strap to do that. And how do you position something like that in order to tack it? Can't wait to see a master at work.

 

And speaking of "plate", I've spec'd the tire carrier piece as being 1/4" thick. It is a 9" diameter disc and I'll weld a stud into it at the top on which I'll "hang" the spare tire and then run a couple of bolts into the disc in the other holes. (I'm thinking it'll be a lot easier when holding that heavy spare up to just align one hole.) But is 1/4" thick enough? There will be a lot of force on that plate as we bounce down the road and I sure don't want it to bend.