Root Rake/Grapple Build ( or at least that's the plan)

[Kernopelli]

Not that it really matters but I'm really curious what others believe these were originally for?

I won these in a local online auction last night for $14.00. I bid on it because the pics appeared to possible be grapple components. Upon picking them up I'm not 100% convinced that a grapple was their original purpose ( primarily because of the gear teeth on the short tines) but that's what they are going to be repurposed for. There are 8 each large and small tines. All 8 short tines are 3/8" and of the long tines, the 2 shorter ones are 3/8" and the other 6 are 1/4". All the gussets ( 8 & 12 each), brackets (2 each) and "gear toothed" pieces ( 8 each) are 3/8". My intent is to make a root rake and grapple much like Pete O's in this thread 60" Grapple Build with short tines on bottom and the long tines on top that act as the grapple. Since my son owns a machine shop and I'm there piddling or helping out almost every day, I have access to all the machines and drop cut material I will need to put this together. My son can take the dimensions and draft the plans in Fusion 360 for me. My only other planned expense will be for a third function control, 2 cylinders and hose. Without giving this much thought yet, my hopes are to build a 60" rake/grapple. I assume this a sufficient number of tines (?) and is 1/4" thick enough for the grapple?

 

[Pete O]

I can see why you were excited to come across those parts and to get them so cheap, but I'd have a few reservations about using them for the basis of your grapple. I'm not sure 1/4" material is thick enough for a grapple. I spent a lot of time exploring websites and looking at specifications of commercially available grapples and I settled on 10mm thick steel for the main laser-cut components and 6mm for all the gussets and having used it for about a year now I would not go any lighter.
If you're planning on using the grapple around the garden on a sub-compact or lawn tractor, I'd say you have a winner but if you are planning on handling large-ish tree debris, logs, stumps etc I think you would be frustrated by how often and easily you would bend the tines.

Also don't under-estimate the cost of hydraulic components! My laser-cut profiles were about 20% of my over-all build cost and that did not include the third-function loader valve that I bought a couple of years earlier.

That all sounds like I'm pouring cold water on your fire, which I hate to do, just there is a lot of work in building one of these and it needs to be robust.

 

[Rockbadchild]

are they are from a seed drill ? ... small ones for fertilizer and big ones seeds and the gear teeth or for depth control, that's my guess anyways... these are probably high carbon steel and at 1/4 each I wonder if they will be subject to breaking...

 

[metalbender]

Built mine out of salvaged rod weeder parts. 48 inches, weighs 250 lbs. Not much to look at but does what I need to do. Digs rocks great.

 

[2manyrocks]

Built mine out of salvaged rod weeder parts. 48 inches, weighs 250 lbs. Not much to look at but does what I need to do. Digs rocks great.

I'm trying to figure out a new set of brush forks with bottom tines similar to what you have there. It would be a big help to me to know what size are your bottom tines? 3/8x3x32? And what kind of cross tubes are you using?

 

[metalbender]

They are rod weeder parts. Bottom ones are 3/4 thick top ones are 5/8. I'll have to go out to measure the length. Good quality material. The beam is 1/4 thick 3 inch square. Bottom is 3 inch angle, 3/8 thick.

 

[metalbender]

Couple more pics of the build

 

[metalbender]

Corrections are in order. Top is 2 1/2 sq 1/4 wall. Bottom is 3x4x 3/8 angle. Bottom tines are 16 inches long. Sq tube between the top tines is 2x2 x 1/4 wall welded between the tines. No reinforcing on the bottom tines lets it dig better. Done with stick.

 

[2manyrocks]

Thank you. I was wondering how you kept the weight down using 3/4 material for the bottom tines. I guess the key is making them 16". I also suppose the bottom angle helps give the bottom tines more stiffening than a tube would have given and helps make up for not having reinforcing on the bottom.