"cutting edge" steel - Fab questions

[RedDirt]

I will be building a narrow bh bucket similar to charlz "narrow bucket" post. This bucket will have relatively light used, eg. not professionally, not daily. My ground is clay with very few small rocks. Like charlz I am going to start out with no teeth since my trenches are fairly shallow (18" 24") and ground is "soft". I'll add teeth later if needed. Cutting edge will be 3" x 3/8" or 4" x 1/2".

My questions regard placing a cutting edge on this bucket.

1. Do I need bone fide "cutting edge" steel stock or can I just use Hot Rolled flat steel and grind the bevel edge myself (taking care not to overheat the metal)?

2. If using a torch to cut a) cutting edge steel or b) hot rolled flat steel, does the heat at the cut destroy the "toughness" of the steel? Is this just at the cut line or does the heat "travel" some distance from the cut and affect the temper of the plate overall?

3. What is the best method to cut a) cutting edge steel or b) hot rolled flat steel to preserve their tough qualities? I have a bandsaw, hand hacksaw, Sawzall, abrasive chop saw, torch, and thin grinder blades at my disposal. I don't know anyone with plasma equipment. I'm thinking a tough (Lenox) bi-metal blade in the Sawzall may be best and least damaging. Like cutting stainless plate, firm, steady feed pressure may keep the Sawzall blade from dulling and case hardening.

4. If using high carbon hot rolled steel and beveling the edge myself should I temper the piece before welding it on the bucket? Before or after the beveling is done?

5. Does pre-heating before or "slow cooling" after welding help preserve the toughness of these two metals?

Thanks for any feedback on any or all the questions above.

 

[Egon]

Use the real cutting edge material. Larger size will be better and make the bucket stiffer. Also put some on the sides of the bucket.

Cutting with a torch works well. Weld as normally but you should be using rod made for the cutting edge. Don't worry about heat. It will all be okay.

At least that worked on my cutting edge but I didn't do the cutting or welding!

 

[mboulais]

Anytime you are cutting metals keeping it cool is required to preserve hardness. Cut with a saw and cool with water. An assistant can squirt water on the blade with a recycled windex bottle while you run the sawsall.

As far as using high carbon steel, yes you can do it. It will be easier on your cutting tools too. Heat treating a cutting edge of any kind involves a couple steps. First is hardening. You will need get the edge very hot, and as evenly hot as possible. Ideally you will heat it until it is non-magnetic, somewher in the bright red range. After reaching that temp quench it with water or oil. Now the edge will be hard. It is too hard though and needs to be tempered. Polish the surface so you can see the colors run in the metal. Heat the edge until it turns medium blue.

 

[DWW68]

REdDirt,
Check around at shops that do repairs on construction equipment. You may be able to find a used up cutting edge from a dozer or something that woud fit your needs. An abrasive blade on an angle grinder will cut thruogh it. When I cut the one that I used, I cut about half deep and snapped it in half. In fact, i think I still have a piece left over that would be big enough for what you need. You could have it but I do not know what shipping would be. If interested let me know how long of a piece you need and I will verify that it is long enough.
Dan

 

[RedDirt]

REdDirt,
Check around at shops that do repairs on construction equipment. You may be able to find a used up cutting edge from a dozer or something that woud fit your needs. An abrasive blade on an angle grinder will cut thruogh it. When I cut the one that I used, I cut about half deep and snapped it in half. In fact, i think I still have a piece left over that would be big enough for what you need. You could have it but I do not know what shipping would be. If interested let me know how long of a piece you need and I will verify that it is long enough.
Dan

Dan,
That would be great; thanks for the offer. What is the cross section dimensions and length of your piece and I'll calc the weight and check shipping. I'll need 38-40 inches long if I do the sides and bottom but only 8-9 inches if I do the bottom only. Something like 3/8"x3" or 1/2"x4", bevel edge on one side is what I'm looking for.

 

[Renze]

Red Dirt, at the company i work, We convert Mercedes Sprinters to light 5th wheel tractors with air brakes and sometimes air suspension.
With the air suspension kit, the original leafs are replaced and thrown away, so i have access to cheap leafs.

Spring steel is allmost as hard as a "real" cutting edge, but can usually be obtained a lot cheaper. Perhaps there is a truck shop somewhere near you that replaces broken trailer leafs every now and then. To them its just scrap, but as abrasive resistant material, it is very economical

Putting these steels into a band saw will dull them within 2 cuts. i had best results with the angle grinder. It takes a bit longer than mild steel but it doesnt wear premature.

 

[DWW68]

RedDirt,
The blade thade I have is 58 1/4" long with bevel on both sides
11/16 thick
5 1/4" one end, 5 1/2" center, and 5" at other end
I was going to use it for a tooth bar but after I received the teeth, I found out it was to thick for me to use.
I attached a picture so you could see it.
For shipping purposes my zip is 14037.
Dan

 

[RonMar]

If this is going to be a light duty bucket, you could just add a re-enforcing strap (4"X 1/2") along the cutting edge and run several weld beads along the edge of this strap(upper part of attached pic), then grind down the welded edge material into a cutting edge(lower part of attached pic). If you lay down your welds carefully, it can require very little grinding to finish the edge.

Ever try to cut thru a weld with a sawsall? it works great in the steel right up to the point where the blade starts chewing into the much tougher weld metal and quickly chews up the blade.

I have had good success with these weld hardened edges over the years, and if it does wear down, it is easilly built up and reshaped.

If it dosn't work, you can always add a "hardened" cutting edge later...

Good Luck

 

[RedDirt]

Thank you all for your replies.

Renze,
That is good to know about the toughness of spring steel. But aren't these usually arched? It would make fabricating something straight rather difficult. I suspect if you were to heat the spring to bend it straight you'd loose the tough properties. They may make good weld-on bucket teeth.

Dan,
Regrettably I think the cutting edge piece you have is too big for my needs also. Perhaps another member could use it. Thanks for the offer.

Ron,
Thanks for the tip. Sounds like this would be worth a try for my lightly used bucket, especially if I can't find anything locally.

 

[Berniep]

I haven't read the other threads about buckets so this might have been covered there. If so I apologize.
First, I was always under the impression that cold rolled steel is a little tougher than hot rolled because it is more work hardened. At least thats what my local supplier told me.
Second, if you have a stick welder you can get some "hard facing " rods and weld some beads on the cutting edge and grind them to shape and have a very hard edge that is as resistant to wear as a genuuuwiiine cutting edge.
Ask at your local welding shop.