question about building my own post hole digger hydraulic down assist

[grsthegreat]

i have a speeco model 65 post hole digger, about 10 years old. i contacted the manufacturer to see if their hydraulic down-force kit will work on the older models, and the tech people told me NO. id have to replace the main body to use their kit. well, thats not going to happen. so heres my problem. i have a plasma cutter so i can make my own brackets, and i can buy a single acting cyllinder from surplus center. but i get confused about the relief valve and what its purpose is. i take it its to adjust the downforce pressure to a lower value??? will any 3 port relief valve work??? i see one at surplus center
Surplus Center - 1/2 NPT 16 GPM 1000-2500 PSI RELIEF VALVE
its 1/2", adjustable from 1000 - 2500 psi. what do you think. The overall project looks doable, and pretty easy. it would be nicer if Speeco had a model that fit, but i do like challenges.

 

[beenthere]

I like your plan.
What did you use to make the great drawing?

 

[grsthegreat]

actually, i found it on the internet.

 

[MtnViewRanch]

The relief valve serves two functions, so you need to be sure that you get the proper one. It allows the piston to collapse at anytime, this way when you raise your 3pt you don't need to worry about opening a valve to let the hydraulic collapse. The other purpose is that when you are drilling hard ground, you have the hydraulic under constant pressure. As in you have the lever that extends the ram continually pulled so that there is a constant pressure on the ram( the excess fluid just bypasses) and it is continually extending to make up the difference as the auger goes deeper in the ground.

Does any of that make sense? :confused2:

I have to tell you, I would look around for the most economical kit, buy that and do whatever modifications that need to be done to it. I doubt that the 2 big plates need to be modified other than maybe some holes drilled. My guess would be that the bracket that those bigger plates bolt to is the piece that would need to be changed or just make a new one from scratch. A person is usually better off modifying an existing unit vs making the whole thing from scratch, especially when you are not even sure what or why some parts are even there.

Just my :2cents: trying to help.

 

[grsthegreat]

The relief valve serves two functions, so you need to be sure that you get the proper one. It allows the piston to collapse at anytime, this way when you raise your 3pt you don't need to worry about opening a valve to let the hydraulic collapse. The other purpose is that when you are drilling hard ground, you have the hydraulic under constant pressure. As in you have the lever that extends the ram continually pulled so that there is a constant pressure on the ram( the excess fluid just bypasses) and it is continually extending to make up the difference as the auger goes deeper in the ground.

Does any of that make sense? :confused2:

I have to tell you, I would look around for the most economical kit, buy that and do whatever modifications that need to be done to it. I doubt that the 2 big plates need to be modified other than maybe some holes drilled. My guess would be that the bracket that those bigger plates bolt to is the piece that would need to be changed or just make a new one from scratch. A person is usually better off modifying an existing unit vs making the whole thing from scratch, especially when you are not even sure what or why some parts are even there.

Just my :2cents: trying to help.

you know..that made alot of sense. i went ahead and ordered the hydraulic kit made by Speeco (the manufacturer of my post hole digger) and will retrofit it to fit my unit. i know it wont fit out of the box..but with some revisions it will work

 

[Chilly807]

Now that's an interesting project... I have an extra hydraulic cylinder that I was debating what to do with.

I think I'll hang on to it, and over the next while start piecing together what I need for the project.

Thanks for the inspiration,


Sean

 

[MtnViewRanch]

Now that's an interesting project... I have an extra hydraulic cylinder that I was debating what to do with.

I think I'll hang on to it, and over the next while start piecing together what I need for the project.

Thanks for the inspiration,


Sean

Hydraulic cylinders are relatively cheap, just because you happen to have one doesn't mean that you would even be able to use it for this application.

sean, reread this thread. Unless you are very familiar with ALL the parts needed to make a down pressure kit, and understand how they work you are waaaaaaaaay better off to just purchase one. If one part gets done wrong, you can very easily end up with a damaged PHD or someone getting hurt. Not worth it in my opinion.

Just my :2cents:

 

[MtnViewRanch]

you know..that made alot of sense. i went ahead and ordered the hydraulic kit made by Speeco (the manufacturer of my post hole digger) and will retrofit it to fit my unit. i know it wont fit out of the box..but with some revisions it will work

If you don't mind me asking, how much did that kit run you? Just nice to know so that other people looking can have an idea.

 

[grsthegreat]

If you don't mind me asking, how much did that kit run you? Just nice to know so that other people looking can have an idea.

$256.00 total, includes both brackets, all bushings, hydraulic ram and regulator, hydraulic hose and coupling, all bolts and attaching block.

I was thinking i could build my own, but i was afraid to overpressure the ram and damage my tractor or post hole digger. i figure the cost of the ram at surplus center at around $65.00 plus both adapter ends, the regulator at around $49.00 plus the steel, hose, adapter would have cost me approx $179 (from the prices i was able to find from supply houses)...so this wasn't much more, and i get the brackets. i know i can modify it to fir my unit with minor adjustments.

i like to take on these projects for the fun of it....but i dont want to get someone hurt in the process. and to go thru that much work to save $50.00 wasnt worth it.

 

[MtnViewRanch]

$256.00 total, includes both brackets, all bushings, hydraulic ram and regulator, hydraulic hose and coupling, all bolts and attaching block.

I was thinking i could build my own, but i was afraid to overpressure the ram and damage my tractor or post hole digger. i figure the cost of the ram at surplus center at around $65.00 plus both adapter ends, the regulator at around $49.00 plus the steel, hose, adapter would have cost me approx $179 (from the prices i was able to find from supply houses)...so this wasn't much more, and i get the brackets. i know i can modify it to fir my unit with minor adjustments.

i like to take on these projects for the fun of it....but i dont want to get someone hurt in the process. and to go thru that much work to save $50.00 wasnt worth it.

That is a great price and as you said, you wouldn't have saved that much money by gathering up all the parts yourself.

Thanks for posting. :thumbsup: