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?

 

[J_J]

Slowmandown,

Te web site listed below, are the ones that supply kits for the CAD plans. They sell the pins in different lengths, and they are 63/64. They also have the bushings/tubing that the pins fit into. You might warp some of them while welding, so get yourself a good 1 in reamer, and touch up every bushing. Remember to bore holes for the grease fittings.

You can get the valves from Ebay, Surplus Hydraulics, Baileynet.com, and Metkit,com , plus some others. I modified the 4 X 4 sections somewhat for more reach. I also adapted the M600 to fit the lift arms on my PT-1445. You can see it mounted in one of the pictures, and the out riggers are installed. I also have three buckets that I can use. I built one of the buckets that Metkit offers. To bend the backside of the bucket, you can support the long part edges on something like a 2 x 4 and drive your car/truck over the center, then place it on some 4 x 4, and drive over it again. Once you have a bend started, weld the back end down, and then put a chain around the bent piece of metal, put a hydraulic porta ram on the chain and tighten it down as necessary to press/pull it into the shape of the bucket. Tack it as you tighten up. Heat on the backside will help the bending also. If you are not secure with your welding, take the bucket and all parts to a good welder, and let him do it for you. Be sure to get a firm dollar amount on the welding.

On boring out the holes for the bushings/tubing, you probably have read about some of us using the bi-metal hole-saw bits. They work pretty good if you keep them cool with water air, or cutting fluid, with a slow speed on the drill press. They make carbide hole-saw bits also, and they cut really nice. When you make your pilot holes in the 4 x 4, drill through both sides without moving the 4 x 4. Then bore the large hole, turn it over and bore the other hole. Right before you start to tack things together, take the cylinder bushings, hydraulic cylinder and put everything together, and lay it up to check alignment, fore and aft, and side to side, the check fitness, If things look good, start tacking. things together.

Since you are building the whole thing with engine, etc, they should have suggested a mount and pump size. The reservoir is usually sized to the GPM of the pump. 5 gal pump, 5 gal reservoir , use a ten micron filter.


With the engine running at 3600 rpm, pumping 4 GPM, it will take a pump of .3 cuin, at 3000 psi and will take about 8 HP to drive it.

 

[Destructo_D]

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...

Good call on machine builders network.... The reason the creator started the site was, he was building... still is building the cadtrac and wanted to keep in contact to gain and share ideas with and from other people building plans from CDP... Awesome site with great info

 

[SLOWMANDOWN]

Geez! Thanks again for all the replys. If I understand correctly then my tank and motor are good enough and need a 4GPM pump. The cylinders are 2" and all the bushings are supplied with the kit. If you need DOM tubing, supposely seamless, the minimum length is 10FT that you can buy here. As far as the welding I believe since I have enrolled in a trade school for welding instruction, my welding has improved, but mostly I can now reconized between good and bad weld by looking at it, and have learned to watch the arc and puddle properly. This does not mean I consider myself as a good welder, on the contraire, I'm still a hack but my welds will hold. As far as recommendations go my kit was for attaching the BH to a tractor, and I was going to but desided to make it as a stand alone. So a hydraulic powerplant is be needed. I will look into the 63/64 pins next week. What grade steel pins are needed? One question that I have been wondering, is a 4GPM pump say at 1500PSI on a 9HP motor with 2" cylinders is it enough for simultaneous cylinder movements? Or will I have only consecutive cylinder movements?

 

[David Devuono]

I made my bucket out of 3/16. First cut the rounded side pieces. Then weld up the back side at one end, then using those carpenter pipe clamps or should I say abusing, bend the backside around the arc welding as you go. I used 1/4 inch on the back and remaining portions, partially cause I did not get enough 3/16

 

[dfkrug]

I made my bucket out of 3/16. First cut the rounded side pieces. Then weld up the back side at one end, then using those carpenter pipe clamps or should I say abusing, bend the backside around the arc welding as you go. I used 1/4 inch on the back and remaining portions, partially cause I did not get enough 3/16

I agree that 3/16 is plenty thick. My early CADDigger plans called for 1/4"
for a 13 inch wide bucket. I wrapped it like you did around the curved sides,
using a cable come-along and an OA torch for extra heat. I was surprised
that I was able to bend such a thick and wide plate. The finished bucket
weighed over 75 pounds, as I recall.

 

[SuperDuty335]

This is off subject but what hole saws do you guys recommend for boring in steel?

 

[Dongerosa]

Off the subject topic....bi-metal cutters is what you need.

Morse Bi-Metal Hole Saws - HermansCentral.com available at HermansCentral.com

Don't know good manufacture from a bad. I don't remember what I bought.

Picture is of drilling a 1.5 inch hole for a CDP build.

Bill

 

[dfkrug]

One question that I have been wondering, is a 4GPM pump say at 1500PSI on a 9HP motor with 2" cylinders is it enough for simultaneous cylinder movements? Or will I have only consecutive cylinder movements?

Yes, you will practice and learn to use your valves simutaneously, whether
or not you get the joystick controller for your valves. The is about right
for pressure, volume, and engine hp.

You can by DOM by the inch or foot from places like Metkit and others, BTW.

I just restocked my 1.000 ID DOM and found some locally for $1.50/inch
and was able to buy an 18" piece.

 

[philbuilt]

To bend the back plate for your bucket. If you have a hydraulic press you could turn that into a small press break. Weld some 2" angle to a plate to create a valley and set the plate on it put some bar stock on top of the plate and press. move a few inches and repeat. This can get you close. I have a 20 ton HF press and this worked for 1/4" plate 14" wide.
Good Luck
Phil

 

[SLOWMANDOWN]

Cool on the bending info, yes I have a 20 Ton H press. I imagine that this method of bending will make small segmented tangent type curves. sorry still no Photos but will try to get some over the weekend.