scrapyard box blade...first fabrication project

[jenkinsph]

You can cut the slots with either the plasma or gas torch, consider adding the reinforcements regardless which will both strengthen the slots and make a neat appearance.

My policy is to farm out machining only when necessary, while I would hire a machine shop to cut a key way and mill a head the simple cut and notch stuff I like to do myself.

 

[ovrszd]

My policy is to farm out machining only when necessary, while I would hire a machine shop to cut a key way and mill a head the simple cut and notch stuff I like to do myself.

Me too. I built my shop wood stove several years ago without a cutting torch. Used my stick welder to make all the cuts including cutting a 24" diameter piece of pipe for the barrel.

 

[Aussiebushman]

Thanks - I looked up more info about using a stick welder with the amps cranked right up to make the cut. That should work fine.

Regardless, thanks for feedback on the reinforcement That will strengthen the job greatly.

Cheers

Alan

 

[stormpetrel]

Yes, Plasma would be the go. but my use for that would be limited, so it might be better to get the local engineering shop to cut the holes. What do you think about my alternative suggestion to cut U-shaped slots, insert the tines and bolt on a heavy cover plate?

Love your comment about the "welding police." I work in the bush with a 10KVA generator and 120A stick welder and a mate says my welds look as though they were done with a knife and fork!

Cheers from Oz

Alan

I think your idea would work great!

As far as the welding police....my first couple of projects have been "heavy" fabrication (for a teensy-weensy welder) and I have had good luck. That all went out the window when I started to build a cart for my welder & plasma cutter today. I am very finicky about clean, beveled surfaces with good fitment. AND......I remember reading somewhere about tack-welding stuff first. But I either forgot about that, or figured it didn't really apply to me. So my cart frame is a little warped!!!

I guess I'll adjust the height of the wheels a little bit to account for the warpage, and no one will be the wiser:laughing:

One last thing: I bought a 7&1/4" metal blade for a skil saw, intending to use it to cut 1/4" plate steel. I never used it because I got the old beat up plasma cutter going good. I found an old 8&1/4" Hitachi slide saw in my attic and put the blade on it. Instant metal saw!! It did the 1" square tube and 1" angle iron cuts beautifully!!:dance1:

 

[ovrszd]

As far as the welding police....my first couple of projects have been "heavy" fabrication (for a teensy-weensy welder) and I have had good luck. That all went out the window when I started to build a cart for my welder & plasma cutter today. I am very finicky about clean, beveled surfaces with good fitment. AND......I remember reading somewhere about tack-welding stuff first. But I either forgot about that, or figured it didn't really apply to me. So my cart frame is a little warped!!!

I guess I'll adjust the height of the wheels a little bit to account for the warpage, and no one will be the wiser:laughing:

Someone with more technical knowledge than I might explain this, but, a MIG welder will distort and pull metal REAL BAD. Way worse than a stick welder. You gotta tack everything, at each corner, several times at a splice, varying the tacks, one side, then the other side, then back to the first side, several times to get it to stay in place. I've even had tacks break when welding on the opposite side. I messed up plenty of projects in the beginning with a MIG welder. I had always welded with a Lincoln stick welder before. Don't feel bad. Think of it as a learning curve!!! You aren't experiencing anything everyone else didn't experience. At least you are honest and modest enough to admit it!!! :thumbsup:

 

[ishiboo]

I would personally buy a cheap cutting edge off a KK or something, I definitely think there is an advantage to a curved cutting edge. Box blade looks great though!

Without having a plasma, I believe you could easily cut those holes in 2" tube with a recip saw or even better, a small metal cutting bandsaw, and a cutoff wheel. Cut the top/bottom slots, and then use the wheel to cut the front/back. You could then weld up the overage from the cutoff wheel.

I like the way your locks are done for the shanks... the cheap KK I have is fine except those are very small pieces of metal a pin sticks into against the steel tube. Your method looks a lot better and not much more work/money!

 

[joshuabardwell]

I love your box blade, and I'm really impressed with your fabrication skills. I will make two suggestions:

1. As others have suggested, commercial blades have reinforcement on the back wall to stiffen it. A piece of angle-iron welded across the top of the back, at least, but something along the bottom as others have suggested would also be good. On mine, the back wall has just been bent to a right-angle at the top, in a brake, but that's probably not something you can accomplish, especially after the fact.

2. The most obvious weak spot in your design is the central "down-tube" (that's what it would be on a bike) on the three-point frame. At the VERY least, you should rotate that piece ninety degrees along its long axis. Most of the stress on the blade will be trying to torque the back of the blade down and towards the front of the tractor, around the lower lift pins. This torque is opposed by that "down-tube", but as you can see, if you have that piece of stock flat, it's very weak in resisting that force, since it wants to bend along its flat direction, and is very stiff along its tall direction. On my box blade, there are actually two of that piece, running left and right of center, and they are oriented up-and-down, not flat. Alternatively, you could replace the piece of flat stock with a piece of tubing. If you do any of this, do it after welding the angle iron to the top of the back wall, since that'll change your measurements.

 

[Arc weld]

Don't try to cut the slots for the rippers by turning up a stick welder. You'll make a heck of a mess and it will be hard to clean it all up. If you don't have a cutting torch or a plasma, drill a hole at each end and then either drill more holes in between or just the cut out between the holes. A recip. saw or jig saw could do this. Even if you have a torch, drilling the ends of the slot is a good idea and then use a straight edge for your torch to cut out between the holes. Be sure the tip is real clean. Maybe a small zip disc in a grinder would cut the slot too? If it cut a little further than you wanted, just fill the gouge in with weld and grind it flat. It wouldn't affect strength. If the corners at each end of the slot have to be square, and not rounded from drilling, that's easily accomplished with a saw or grinder as well. I think my shanks have a curve to them.

MIG welding should actually lessen warping because it's a faster process with less heat input than say stick welding. That's why it's so popular for auto body work. The reason you seem to get more warpage with MIG is because it's the best process to use for thin sections. Sometimes you have take steps to combat warping like not welding all in the same place at once or clamping a heavier piece on the backside of the piece your welding, etc.

 

[Aussiebushman]

Thanks Arcweld. Good advice

Most cuts I make in metal are done with ultra-thin grinder blades and I can't see any reason why the "fore and aft" cuts can't be done that way. It wouldn't be too difficult to make the last cut also with the grinder because Stormpetrel's vertical "tabs" and an extension of the weld would cover any overcut anyway. The reinforcement on the forward edgeas noted by others will help greatly to stiffen the whole assembly.

 

[ovrszd]

Not to distract from this build, but since we are talking about scarifier toolbars and their design, I want to show you these pictures.

First one is of the scarifier toolbar on the John Deere road grader I run. This is with the scarifiers installed.







Next picture shows a scarifier removed. If you look closely at the tooth you can see it has notches in the rear edge. The slot in the toolbar is big enough for the tooth to drop thru. When you get it at the height you want you push it rearward locking it in one of the notches. Then you drop the curved pin in front of the tooth. This prevents it from getting out of the slot. When the tooth is used the force pushes it tight against the pin so there's no chance of it coming out and the tooth is still engaged in the slot. Very simple to change height or remove teeth. No tools required. I always thought if I was building a toolbar with scarifiers, this is how I'd fasten them in.