Tractor backhoe - homemade

[BFreaky]

This material comes in a hardened and ground state, at least here. I will try to weld it as you said although I did it before but the welds were not so thick as you mentioned. Problem is I don't have line boring machine or bohrwerk and the welds tend to pull...usually I put all the bushings in place, push a pin through and weld it all in place. Most of the time it's precise enough but ofcourse it's better to fine drill it after all the welding is done. At this point I have no other way to do it

 

[Renze]

Are all your pins the same size ? Then you can make the holes 0.5mm undersize, and buy one or two hand reamers to ream them to a fitting of minus zero, plus a few hundreths (H7 fitment reamers are most common)

 

[Renze]

Google Image Result for https://i.ebayimg.com/images/g/V3wAAOSwB-1YSWJ/s-l3.jpg

You can also get adjustable reamers, but setting the diameter takes precision and the diameter adjustment range still is maybe a 10mm or so

 

[BFreaky]

Yes, 45 mm. Except main pin which is 60 mm. How would I align it through both holes 120 mm apart?

 

[sixdogs]

I hope new one will be even better...at least that's the idea

No doubt it will be. Any idea of total build time in both in hours and months?

 

[texasranger556]

Yes, 45 mm. Except main pin which is 60 mm. How would I align it through both holes 120 mm apart?

Have you looked into building a line boring rig?

 

[BFreaky]

Yes, I may just build one. I've got an old drill press which could maybe do it.
Sixdogs, I'm still in prep mode, build did not start yet. I'm waiting till I gather a pile of parts then it's on

 

[11B2620]

Curious if you could explain the electric joystick? Looking into making my backhoe with two mechanical joysticks into the same on a small excavator, all electric. I was trying to figure out your amount of levers and how you were saying about being able to switch something??

 

[BFreaky]

I will use 2 joystick levers connected with metal cables (1st picture) and electric diverter valves so each function can be diverted. All you have to do is hold a button to switch between cylinders. I can draw a schematic if you want

 

[rScotty]

Everything . The point is to have hard pins to get as much uptime as possible. Bushings are cheap and can be replaced quickly but pins are not

Well, hold on here. There are plenty of machines that use the hard bushing and softer pin philosophy. I don't believe it is such an obvious decision. There are also sleeved bushings available and the ease of repair by small shops to consider. Not to mention the initial cost and that different soils will abrade in different fashion. In my mind there are advantages both ways.
rScotty

 

[Kyle_in_Tex]

I was thinking it is much easier to replace a pin than a bushing too???

 

[4570Man]

I was thinking it is much easier to replace a pin than a bushing too???

It is.

 

[4570Man]

I don’t foresee it being a problem either way. Commercial backhoes go thousands of hours before changing them.

 

[hseII]

I was thinking it is much easier to replace a pin than a bushing too???

As long as you can get the pin out without compromising the bushing &/or base metal/housing.

Hard Pins for me.

 

[rScotty]

I was thinking it is much easier to replace a pin than a bushing too???

Yes, and that's probably the first thing that jumped out of me. Not only easier physically, but less expensive. The average guy with a garage can handle repairs to a fairly large hoe. Or if he had rather, there are literally thousands of small welding/repair shops that can. Pin wear becomes more field-repairable & without the whole problem of weld cracking and heat treat.

Then it occurred to me that this is (another) whole field of mechanics that I know almost nothing about. I simply haven't sat down and worked through the arguments for hard vs soft pins and bushings in high pressure, low speed applications with grease.
Just to check that I'm not hallucinating, I just went out to my JD310SG and touched a file to a couple of the main BH pins in the bucket and booms. They are soft, although of large diameter - the smallest is around 2.25" across. That's about what I would expect. Lateral movement is constrained by a thin hard washer and big cotter through a hole in the pin.
rScotty

 

[Kyle_in_Tex]

I want to hear about an easy way to replace bushings?

 

[4570Man]

I want to hear about an easy way to replace bushings?

They sure aren’t easy to do on my backhoe. I’ve never actually changed one and they’re in perfect condition after 2400 hours, but I contemplated doing it when I couldn’t get grease in 2.

 

[dfkrug]

I want to hear about an easy way to replace bushings?

The times I have done it on my Bulgarian backhoe attachment, it has not been easy. These plain bearings were only 25mm and 30mm, which I can now get from China fairly cheap. Teflon coated. The toughest one I did was in 5 segments, and I welded some scraps of steel on the inside so my drift pin could get a purchase to drive them out.

 

[dfkrug]

I just went out to my JD310SG and touched a file to a couple of the main BH pins in the bucket and booms. They are soft...

I found my Kubota pins to be fairly hard, and my Deere pins, soft.

 

[rScotty]

I found my Kubota pins to be fairly hard, and my Deere pins, soft.

Same on mine. Neither Kubota nor Deere has too much overall wear, although the Deere with 6000 fairly hard hours but decent service schedule is beginning to show too much slop at the QC bucket. The swing, table, and booms are all still tight - including the extendahoe.
My experience is that it isn't uncommon for Deere 310s to benefit from new pivot pins in some locations after 7 to 10K hrs. Pin replacement is well within the capability of the home mechanic. Given a saw and a drill press you can even make your own from round stock if necessary.
So far I'm kinda liking the softer steel pin & hardened bushing approach.

But now my curiosity is up and I'm wondering just what argument drove European & Japanese designers to favor different steels in the same application?
rScotty