Your metallurgical thoughts on this tool.

[roofbutcher]

It takes shingles off roofs. The teeth are subject to punishment and abrasion. The shaft is air-hammered upon and used as a pry bar.

What would you like to see used for materials and/or process in the construction of this ripper? Would it be easier to forge, fab or cast?

 

[Ron]

That's an odd design for a shingle ripper; however, considering the use it will get, I would suggest a forged tool. I can't see a casting holding up to that punishment and a welded tool like you've shown will probably have fatigue issues.

I'm curious...is this a design you are trying to patent? Most shingle rippers are flat with a heal for prying. This one looks like a variation of a BUR ripping tool. Wouldn't this one leave a lot of shingle residue around the nails? If you've found a better way...go for it. The roofing industry needs all the help it can get!!

 

[roofbutcher]

I was kinda liking a forged. Is it possible to forge that profile?

The casting guys say that their 1050-ish casting would perform on a par with or better than the welded version.

The welded version is performing well in the field. It leaves a clean nail and makes powered shingle stripping viable. It's patented, and just starting to sell. Details on

http://strippingiron.com/.

It is made from 1050 teeth, mild spine, and 4140 shank. It is quenched and several differant tempers applied. More abrasion resistence on the teeth would be nice and also that shaft gets knurled by the ball berrings at the retaining ledge.

What would the ideal material(s) be for the shank and/or teeth? What would one expect to see a jackhammer chisel made of?

 

[TVP]

rb,

The exact geometry of your welded prototype will be difficult to forge, for several reasons. First, the aspect ratio of the blades is high, meaning that they are long/tall and thin, which is not ideal for forging. Adding some draft to the surfaces would help, but I am not sure if that will then interfere with its intended use. Second, there are two protrusions that are welded where the hex shaft meets the flat plate. These would be difficult to fill out because they are perpendicular to the predominant plane of the part.

I would probably consider this as a 2-piece design: one part for the blades probably the flat plate and another part for the shaft and the tabs. Forge the shaft & tabs together in one piece, then join to the other part, which looks like it could be cast quite readily, although this is not likely to be as favorable as a forging for finished mechanical properties, toughness, and durability.

Jackhammer chisels are made from quenched and tempered steels, such as 4340 alloy steel or S7 shock-resistant tool steel. Induction hardening can be used to locally increase the surface hardness while retaining a ductile, fracture resistant core.

 

[roofbutcher]

Yeah, she's a tough weave.

I'd like to see more abrasion resistance on those teeth, but casting and welding both have trouble when exceedind 50 points of carbon. Any Ideas?

 

[btrueblood]

Having a replaceable part for the wear surface would be the way I'd go.

Some bucket teeth shells on backhoes are forged high-carbon steel, with the tip quenched, and the rear part of the tooth kept soft. You install them by "crimping" the back side of the tooth shell over a spine, and can easily bang them back off when it's time to replace the teeth.

Another methodology, for bigger backhoes, use a "flex pin", see

http://www.colemanequip.com/HowToSelectABucketTooth.asp

 

[Metalguy]

This seems like a good application for an abrasion-resistant welded hardfacing on the wear surfaces. That could allow you to use cheaper materials/heat treatments for the rest of it.

If the wear areas of the teeth don't see much impact, there are some very hard wear resistant weld materials available which will easily outlast any heat treated structural/low alloy steel.

With impact, you'd have to give up a little wear resistance, but probably not too much.

Also consider some powder metallurgy "knife-blade" steels from Crucible Steel.

Gold is for the mistress - silver for the maid
Copper for the craftsman cunning in his trade.
"Good!" said the Baron, sitting in his hall
But iron - cold iron is the master of them all.
Rudyard Kipling

 

[roofbutcher]

Good ideas, I'll be looking into them. Thanks.

 

[Frederick]

Cryogenic processing will increase the abrasion resistance and the toughness.