Freakaccident's tube chassis crawler build...

[freakaccident]

I have decided to build my own tube chassis buggy. I am going to use Harley Designs plans for the Poison Spyder Customs Venom Chassis. I will be using 3/16" brake line from Autozone for the tubing. I will be using a mapp gas torch to braze the tubes together with bronze brazing rods. I will post pics as the build progresses. Please ask questions as I will be happy to answer them.

So far I have built the first piece. Here are a couple of pics.

 

[RMIII]

This is interesting. I'm following to see how it goes. Please post as you go!

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[freakaccident]

Here are some of the tools I am using.

I bought a little mini bench grinder at Harbor Freight for $30 and it has a dremel type snake attachment so you can use dremel bits in it. This thing is awesome. It has a grinding wheel on one side and a deburring wheel on the other.

I bought this small suction cup vise at Harbor Freight. It is awesome as well. It has channels in it that the 3/16" brake line fits in perfectly for clamping it down to cut or braze the pieces. I bought a piece of sheet metal at Home Depot to stick it down to and so I don't burn my work bench.

Tubing cutter from Harbor Freight:

Tubing bender also from Harbor Freight:

I plan on using 3/16" Drremel chainsaw chain sharpening stones to fishmouth the tubes.

 

[freakaccident]

Second piece is done. This one turned out better and took a lot less time. The brazing is really cool. Once you get the hang of melting the rod into the tubing it is really fun.

 

[freakaccident]

I think I am actually starting to get good at this!

 

[CODYBOY]

You need to remember that you are not fusing the pieces, but encasing them, so you don't want to get the material to thin at the joining points. JMO "thumbsup"
Ernie

 

[freakaccident]

You need to remember that you are not fusing the pieces, but encasing them, so you don't want to get the material to thin at the joining points. JMO "thumbsup"
Ernie

It's definitely not thin. In that last pic I didn't fishmouth the tube. I wanted the gap to fill in with rod so it would be really strong.

 

[CODYBOY]

It's definitely not thin. In that last pic I didn't fishmouth the tube. I wanted the gap to fill in with rod so it would be really strong.

OK, just trying to help you out a little. 8)
Ernie

 

[freakaccident]

OK, just trying to help you out a little. 8)
Ernie

It's good. I appreciate any advice I can get.

 

[freakaccident]

Sorry for no recent updates. I have been busy buying, building, and learning to use a 3D printer.

Also I switched from using MAP gas to braze the welds to using oxygen/acetylene to weld them. I was not happy with the heat MAP put out or the speed. MAP just didn't heat the tubing up fast or hot enough and the brazing rods I am using would melt off the flux long before the rod would melt. If I were using the expensive Silver salv stuff it may be different but I already had a portable oxy/acetyl kit and oxygen and acetylene will last much longer is cheaper than the MAP bottles. If you have this option definitely do it. It's so much better and the quality is better too but it's a little harder to master. I was considering TIG but after doing this I wouldn't do it. Oxygen/Acetylene welding is a lost art and make such awesome welds. Much slower than TIG or MIG but oh so nice and I am not welding in large volumes. I am still learning so mine aren't the most beautiful but they are getting better.

I have the base structure built and I also 3D printed a Wraith skid plate. I am still contemplating how I am going to attach the skid plate. There are 4 screw holes on each side of the skid plate for mounting to the chassis and 2 on each side for the lower control arms. The issue is how am I going to drill through the tubes to get the M3 bolts through? There are clearance issues with the tubes boxing. If you have any ideas please let me know. At this point I think the chassis to skid plate mounting bolts will be ok if I drill through both tubes on the outer boxes. The lower control arms will require longer M3 bolts than I think I can get into those boxes. I may try to draw up an MS paint drawing to help make sense of my thoughts. Here are some pics in the meantime:

 

[freakaccident]

Ok so here is an overhead with some M3 bolts to show my issue.

In the first image from left to right you can see:

1. Chassis to skid plate option 1 - Less penetration but room for an allen wrench
2. Chassis to skid plate option 2 - More penetration but would need to use pliers/etc. to screw in.
3. Lower control arm bolt option 1 - Good penetration into skid plate but no way to get it in.
4. Lower control arm bolt option 2 - Less penetration into to skid plate but no way to get it in BUT might possibly be able to angle it in.

Second image show the issue with inserting the LCA bolts.

Do you see my predicament? Any bright ideas?

 

[freakaccident]

Also I can only find that one other person has built this but all I can find are nasty blurred out photobucket pics from this ancient thread:

http://www.rccrawler.com/forum/axial-wraith/527221-harley-designed-venom-chassis-build.html

I would love to see the good pics or more info to help with my build.

Thanks

 

[freakaccident]

I think I figured it out. Not perfect or easy but it will work.
Cut the heads off of the bolts and thread them in as studs using two nuts. I can drill through both tubes and won't have to worry about the head of the bolt.

 

[RMIII]

After looking at your pics and then comparing them to the other build in the link you posted it appears as if your frame is missing some pieces. The skid is attached lower than the tubes you are trying to attach through. There appears to be another section of tubing 90 degrees straight down and parallel to the tubes you are calling the bottom. Solves the clearance issues you are having. If you look carefully at the other build pics you will see they filled in the open space between the tubes with a metal sheet from the lower tubes up to the tube you are trying to attach the skid to. I hope my post makes sense!

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[RMIII]

You can see the lower tubes in this pic and the sheet of metal I was referring to. The skid mounting holes are in the very bottom tubes, resting on the table.

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[freakaccident]

You can see the lower tubes in this pic and the sheet of metal I was referring to. The skid mounting holes are in the very bottom tubes, resting on the table.
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I'm not sure why I can't see those pics in that thread but I see now how he did it. Smart idea. I still think I am going to go my route to reduce the overall height.

How did you get that pic? All I see on the pics in that thread is blur and a photobucket watermark.

The skid plate I printed already gains a few mms over a stock Wraith skid plate so it is possible I will run into clearance issues with the axles so I may in the end need to build plates like he did.

Here is a pic of an M3 bolt going through a piece of scrap tubing I drilled with a 1/8" bit.

 

[freakaccident]

So I am having a lot of issues brazing these joints when there are three parts to braze together. I braze the first two pieces and then later braze the third piece to the other two. The heat basically melts the brazing material from the other two and they are falling apart as I braze the third part to them. This makes sense as I am heating it all together. The problem is that I can't do all three initially at the same time. I am thinking that brazing may not be the way to do this.

Would a flux core welder be a better option for welding this small tubing together? I would love to have a tig machine but I just can't afford it.

Any opinions or help?

Thanks

 

[freakaccident]

I think I may have figured it out. The issue seems that the brazing rod doesn't melt fast enough after heating the joints. I practiced a bit and if I pre-heat the brazing rod just to melting point then heat the joint while keeping the rod in the flame I can get it to melt in before melting the brazing material from the previous joint. Ultimately I think using the expensive silver brazing material and flux would be the answer but that stuff is pricey. Here is a joint I just did.

 

[freakaccident]

I broke down and ordered Safety-silv 56. It isn't cheap so I am hoping I won't use much. The low melting point should help a lot. I will post more when I get it tomorrow.

Thanks for watching!

 

[freakaccident]

So I received my Safety-Silv 56 and flux today. Wow. This is so much better than brazing rods. My main concern is cost.

So I fishmouthed a tube and brazed it to another tube. That would be tube 1 brazed to tube 2 in the picture. I cooled it, cleaned the joint, and then added in the third tube. It turned out really well. The first joint didn't melt away like it did with the bronze rods. My fitment could be better and I should have used a little more solder.

Thoughts?