Arachnid Build, ... or is it! (Highly Modified)

[Bill CNC]

Hmmm, ... Something isn't right, ... I sure don't have very much swing in the suspension. Hell, ... they don't even hang the same. It seems to be bottoming out on the Heim joints (I think). Now nothing is dialed in mind you, and the length of rods are not set up to precisely, bolts facing the wrong way, nut are inconsistent in length, and the top block on arms are not welded to the bottom half. I want to test fit things before locking them down.

Have a look;

 

[Bill CNC]

Ok, ... Now a list of all the tweaks,

1). I made my suspension block, 6.0" wide instead of the 5.0" called out for the plan.

2). The clevis's on the tie rods have .312" pin hole, .375" thread and HAD an opening of .413" roughly, one was .427". I put them on the mill and opened it up to .515" so the rack ends will fit.

3). The spindles have a hole for the tie rod bolt of .312" and Hiem joints on the tie rod have a bore of .375" so I opened up the hole in the spindle to .375".

4). I WANT to weld the bushing brackets in the same position on the block instead of half way down the the thickness of the tubing so I am using spacers to increase the height of the spindles. to spread the A-arms out on the wheel end to match the pivot spacing.

I will post pictures of the tweaks and edit them into this post when I tear down the suspension block later today.

 

[theo]

You need at least cone spacers out on the rod ends top and bottom of the spindles. And you will need them on the outer tie rod end.
Here... http://stores.ebay.ca/QS-Components...889QQ_sidZ61394735QQ_trksidZp4634Q2ec0Q2em322

 

[Bill CNC]

Theo,

I took this into account when making the spacers. If you look this picture, you can see I the spacers with a smaller diameter of the flat on the top of the Hiem joint ball. If anything, it would give me more movement than the cone spacers. Wouldn't you think?

 

[Bill CNC]

Hey guys. Just thought I'd say hello as I'm in the process of building my own Arachnid. Some nice work there so far Bill, looks very professional. Your post has made for some interesting reading, I followed the link from the Spiderkarts forum. I have run into many of my own problems so far, mostly to do with finding suppliers for some of the off the shelf parts listed in the plans. I'm in the UK you see, so the postage costs for the US suppliers make them prohibitive.

Mine is coming on quite well, with the main frame now nearly complete. I have made 2 main changes to the plans; I've stretched the chassis by 5" and I have made the front suspension frame 1" wider too. I have the engine sorted, a 13HP Honda clone mated with a Honda 2:1 reduction wet gearbox. It was a nightmare trying to get the two to fit, as the engine has a 1" output shaft and the gearbox has a 25mm input. Some careful bodging was needed.

I won't take up anymore of your post, I'll start my own once I upload a few pics, but hopefully with 3 of us building the same thing we'll be able to bounce a few ideas off each other (as support from Spiderkarts is a little thin on the ground )

Wobbly,

Welcome to the forum. I hope your build is going better than ours. What made you decide to widen the suspension block to 6.0"?

 

[theo]

Is the tie rod at the spindle jambing.

 

[Bill CNC]

Is the tie rod at the spindle jambing.

Theo,

Nope, I disconnected those to check the travel. I was going to use a nut for a spacer giving me the clearance I need.

Ok, I see where I'm messed up. I have spacers for the spindle side of the bolts, and not the nut and bolt head side. I moved a spacer to the bolt head side and I added a bronze .750" tall bushing and it helped a little. I didn't tighten the nut and it left a little pace to simulate a bushing and I only have 11* angle on the A-arms, ... not touching the ground. It surly doesn't have the 18* in the photo that the designer shows in the plans, and that's touching the ground and the full weight of the Kart on it.

I will mock up some spacers in .5" schedule 40 PVC pipe. It is easy to cut and to test shapes with.

I need to split the spacers up to give me a total of 1.250" of spacers so the centers of the Heim joints equals the distance of the centers of the A-arm bushing bolts giving me parallel A-arms.

Isn't that what I should be shooting for?

Theo, ... thanks for your help, it is greatly appreciated for sure!!!!!! :wink2:

 

[Bill CNC]

Hmm,

I just don't get it, ... look at the spacers, or better yet, ... the lack of spacers that the designer uses. And he has miles of throw.

 

[theo]

Bill how much travel do you have?

 

[Bill CNC]

Well it just goes to show you, ... even an old fart like me can figure it out, given enough time. I broke out the 12+ disc sander and I tapered my spacers and a nut. I now have a 20* hang.

 

[Bill CNC]

Grizz,

I didn't like just but welding the nut's so I bought a bunch of these tall nut's from Mcmaster Carr they are .844" tall. If you hit them on a disc sander, ... The fit inside the tubing. It definitely is easier to keep true while welding them on. Just run a bolt through it to line it up and check for alignment.

Boy, ... this must be your week ... I'll toss 4 of them in with the rest of your parts if you want them. If you don't have a way to put the plats on it, let me know.

 

[The_Machine]

Bill, do you have any bumpsteer?

 

[Silvergrizz]

Hey guys. Just thought I'd say hello as I'm in the process of building my own Arachnid. Some nice work there so far Bill, looks very professional. Your post has made for some interesting reading, I followed the link from the Spiderkarts forum. I have run into many of my own problems so far, mostly to do with finding suppliers for some of the off the shelf parts listed in the plans. I'm in the UK you see, so the postage costs for the US suppliers make them prohibitive.

Mine is coming on quite well, with the main frame now nearly complete. I have made 2 main changes to the plans; I've stretched the chassis by 5" and I have made the front suspension frame 1" wider too. I have the engine sorted, a 13HP Honda clone mated with a Honda 2:1 reduction wet gearbox. It was a nightmare trying to get the two to fit, as the engine has a 1" output shaft and the gearbox has a 25mm input. Some careful bodging was needed.

I won't take up anymore of your post, I'll start my own once I upload a few pics, but hopefully with 3 of us building the same thing we'll be able to bounce a few ideas off each other (as support from Spiderkarts is a little thin on the ground )

Hi Wobbly, welcome to the group. the more the better I say . Good idea to stretch the main frame by 5 inches. My mainframe is done, but it seems quite cramped. I also am using a Honda GX390 clone, but with a Comet TC40. Looking forward to seeing what you have done when you start your own thread. Lots of pictures please. My last 3 days have been spent reading and studying trying to figure out the problems with this design.

 

[Bill CNC]

It looks like it.

I am editing a video I took of it, I will post it in a little bit.

 

[Silvergrizz]

Grizz,

I didn't like just but welding the nut's so I bought a bunch of these tall nut's from Mcmaster Carr they are .844" tall. If you hit them on a disc sander, ... The fit inside the tubing. It definitely is easier to keep true while welding them on. Just run a bolt through it to line it up and check for alignment.

Boy, ... this must be your week ... I'll toss 4 of them in with the rest of your parts if you want them. If you don't have a way to put the plats on it, let me know.

PM sent, Thanks

 

[Bill CNC]

The machine,

Ok, here is a video of the bumpteer, I think. The movement is from the A-arms hanging all the way down, to horizontal. Just click on the picture

 

[theo]

IF you check your head on view of your suspension you can see that the tie rod is angled, try spacing the tie rod down at the spindle this should take it out.

 

[Bill CNC]

IF you check your head on view of your suspension you can see that the tie rod is angled, try spacing the tie rod down at the spindle this should take it out.

Whoo-Hoo!

Theo, ... Thanks, ... BIG TIME!

All I did was reverse the bolt setup and put everything under the spindle are. There is absolutely no bumpsteer looking at it from the top and looking from the front, ... the spindle bolt stays horizontal throughout the A-arms full motion. Man, ... what a relief, it's time for a beer or something.

I will post video tomorrow

Bill

 

[Wobbly]

Wobbly,

Welcome to the forum. I hope your build is going better than ours. What made you decide to widen the suspension block to 6.0"?

I wouldn't say it is going better, I've yet to start making the wishbones . I like the look of those nuts with the chamfer, I'll have to find something similar. I had to widen the front end to fit the steering rack I have sourced, I'll shorten each wishbone by 1" to compensate. I'll go and take some pics and post a thread.

 

[theo]

Bill this could be a dumb question, but does the plans show and call for any camber???