CDP BACKHOE BUILD

[SLOWMANDOWN]

Just starting to piece together the material to assemble from the CDP Backoe kit. I was wondering if other members have had any problems or hints and tips that they would share before I start and go to far. I lurked around for a while and read many threads on backhoe builds and am trying to avoid any major problems. ( ie.: dealing with distortion, aligning, reaming bushings, bending the bucket, etc...). I am by no manner a welder nor a machinist, but have good mechanical skills. I have gathered all the hydraulic cylinders, metal tubes, engine for power, tank etc. I still need a pump ( although I do have a 2 stage pump ) and control valves, and hoses.
So this beeing said I am hoping to gather insight and not look like a JackA infront of my neighbors and inlaws.
PS_ I will post pictures of my progress as I go.

 

[dfkrug]

I have a few suggestions....

I built the CADDigger 728 in the mid 90s. CDP is similar.

The 2-stage pump may work fine for your application, depending on the
engine you use. If going with a single cyl 8-10hp 3600RPM engine, the
pump needs to run at that speed. I recommend a water-cooled engine
salvaged from a m/c. Sometimes you can find them for $50 or even less.
I really like Honda CX500 engines. Quiet, smooth, powerful, and can run
at lower speeds. I tried air-cooled, and they just get too hot. A bigger
engine has the needed ballast, too. When I switched to a 10hp Tecumseh,
I needed to add lead ingots for weight. And wear ear protection.

Use 1/4" hoses, instead of 3/8" or bigger. Easier to route, and your flow
rate is low. Get a new 6-spool stack valve from Ebay or SurpCntr. It can
cost less than a Prince stack valve after you buy all the sections needed.

3/16" carcass for the bkt is plenty, and easier to bend than 1/4". Weld on
wear strips where needed.

 

[J_J]

Just starting to piece together the material to assemble from the CDP Backoe kit. I was wondering if other members have had any problems or hints and tips that they would share before I start and go to far. I lurked around for a while and read many threads on backhoe builds and am trying to avoid any major problems. ( ie.: dealing with distortion, aligning, reaming bushings, bending the bucket, etc...). I am by no manner a welder nor a machinist, but have good mechanical skills. I have gathered all the hydraulic cylinders, metal tubes, engine for power, tank etc. I still need a pump ( although I do have a 2 stage pump ) and control valves, and hoses.
So this beeing said I am hoping to gather insight and not look like a JackA infront of my neighbors and inlaws.
PS_ I will post pictures of my progress as I go.

I have been building my CDP backhoe for a year or two. Other things going on, etc. Most everything is put together now, and needs valves and hoses. I built mine to plug into my Hydraulic Power-Trac. Some hints might be, use 3/16, or 1/4 in tubing for the 4X4 tubing stock. Bore your holes straight for the bushings, and when welding, make sure the tube inserts are aligned. If you use the 1 in DOM tubing for the sleeves, be sure and get the 15/16 pin stock to use for your pins, or use 1 in grade 8 bolts. You might tack those tubes , and fit things up with cylinders, etc, and if everything functions OK, then finish welding. The company below has some nice joystick valves for the backhoe. PM me for data if you want. The guys like to see pictures on here, so take plenty of pictures. Did you order the complete kit plus thumb for the backhoe? I ordered the grapple kit and welded it together. Picture below if I can find it.

Hydraulic Cylinder Components, Products

 

[dfkrug]

Hey, nice grapple, JJ. Got any action pix?

The Baileys link you posted has some good hyd deals, I see. Thx for
posting.

 

[Dongerosa]

Machine Builders Network

here is a link to building back hoes...seem like a good sight to me for scratch/home builders.

I started a CDP mid600 kit 4 years ago...went like gank-busters until boating season now she a just sitting. just need time...

 

[jeff_jeff]

I built the mid-600 a few years back - my two suggestions are:

1. use standard 1" tractor pins, rather than make your own - fit better, work great, and will save you a bunch of trouble.

2. go with 1/4 inch hose to the cylinders -

Jeff

 

[SLOWMANDOWN]

Thanks all for the replys, good link for the valves J_J.I will call them this week. Yes I did get the kit and thumb kit, actually drove to his place to get the kit, friendly guy. My tubing is 1/4 in. which my neighbor milled at work. I'll post pictures later to day, but so far thats all the progress. The engine that I got is a 9HP air cooled chinese motor.What pump do you suggest? The tank is a 5gallon, is this too small? The progress is slow mostly because I needed to improve my welding skills and dealing with the weather. In another month or so winter should break and I'll be able to weld outside and not risk burning down the garage. The bkt called for 10ga. steel, is this to thin? How do you bend 3/16in.? As for the pins, I assume that the bolts are undersized dimensionally, therefor no need to ream the bushings (sleeves)?

 

[SLOWMANDOWN]

Thanks all for the replys, good link for the valves J_J.I will call them this week. Yes I did get the kit and thumb kit, actually drove to his place to get the kit, friendly guy. My tubing is 1/4 in. which my neighbor milled at work. I'll post pictures later to day, but so far thats all the progress. The engine that I got is a 9HP air cooled chinese motor.What pump do you suggest? The tank is a 5gallon, is this too small? The progress is slow mostly because I needed to improve my welding skills and dealing with the weather. In another month or so winter should break and I'll be able to weld outside and not risk burning down the garage. The bkt called for 10ga. steel, is this to thin? How do you bend 3/16in.? As for the pins, I assume that the bolts are undersized dimensionally, therefor no need to ream the bushings (sleeves)?

 

[jeff_jeff]

The specified bucket thickness was fine - I've had no problems with it - It was difficult to bend onto the rounded bucket, anything thicker would be impossible without special equipment.

The bushings clearance depends on how much distortion you get when you weld them on.

Then, it depends on how perfect you want it - if you want very tight clearance, go with the steel pins the plans call for and use a reamer. For normal weekender use, use tractor pins or bolts, and you can use a 1" drill if necessaary to clean out the bushings. You'll have a smidge more slop, but it won't make a difference in a non-industrial application.

 

[dfkrug]

If you use 1.000" ID DOM tubing, you will need pins with enough, but not
too much clearance. I used 63/64 rod that I found at my local steel surplus
seller. 25mm works great, too. 15/16" will give too much clearance. 1"
bolts will work, too, as they are really more like 63/64 OD. OEM tractor
pins can be a problem as many are 1.00" and the bushings are often over
1" for clearance. e.g. my last Kubota's pins were 1.00", but my current
Kioti uses 25mm. Both are pricey.

If I recall, I used a very low displacement Barnes pump (.164ci?) designed
to run at 3600RPM. That is the RPM that many of those big one-cyl
engines are designed to make their power. 5 gal for the res is a bit large
for cyls in the 3" range. Doesn't CDP have recommendations?