Front loader for a B7200

[Paul Allwood]

If you haven't made your SSQA yet, you could consider instead doing the older proprietary Kubota quick attach. I only say this since it seems like all the implements you're going to use you're going to fabricate anyway. The Kubota quick attach is quite a bit lighter than an SSQA setup. I ended up putting one on my B2601 since in New Zealand basically nobody has SSQA, and I would have had to special order it. It was just as easy to order the older quick attach, and it meant I didn't have to modify my bucket.

Thanks Paul. You're right, I'll probably make the implements I'm going to use initially, at least for now. I hadn't considered the older style, and chose to make the SSQA style so that it is compatible with other things here in Australia if I do need to buy something, or even borrow an attachment from a friend. I'm also a bit far down the track to change now.

 

[Hugo Habicht]

PS - I used to model things like this in Solidworks which takes out a good bit of the guesswork..... I've now resorted to hand sketches and plywood or cardboard models, which often means more grinding and re-welding later, but it's the best I can do.

Hello Paul,

I use Visio (or LibreDraw) for planning geometries. Not as powerful as Solidworks but faster than making cardboard or plywood templates. You can group parts and rotate them around pivoting points, so easy to check angles and if you hit something I find it very useful.

Also this web site is handy to calculate deflection of steel sections, so you get an idea what is required so that you can keep the weight down: Link steel calculator

 

[Paul Allwood]

Hello Paul,

I use Visio (or LibreDraw) for planning geometries. Not as powerful as Solidworks but faster than making cardboard or plywood templates. You can group parts and rotate them around pivoting points, so easy to check angles and if you hit something I find it very useful.

Also this web site is handy to calculate deflection of steel sections, so you get an idea what is required so that you can keep the weight down: Link steel calculator

Thanks Hugo.

 

[North Idaho Wolfman]

If this is as far back as you can get the cylinder to go, it's very likely that there is a stop inside the cylinder that needs to be removed.

What bore and stoke is the cylinder?

 

[North Idaho Wolfman]

 

[Paul Allwood]

If this is as far back as you can get the cylinder to go, it's very likely that there is a stop inside the cylinder that needs to be removed.

What bore and stoke is the cylinder?

View attachment 160976

It's 2.5" bore x 8" stroke. This model of cylinder does use an internal stop, without it it's the same as a 10" stroke cylinder. I can only assume they do it so they have more common parts in manufacturing.

So with the internal stop in place, it still gives a stroke of 8" (LA344 spec is 7.7"). The stop can stay where it is - this is the stroke I want to match the LA344.

 

[Paul Allwood]

With the original geometry that was based on plywood and cardboard models, I ended up with a total bucket rotation of 110 degrees with my first set of steel brackets. I was aiming to match the LA344 that I'm roughly copying - this gets a total bucket rotation of about 140 degrees.

Out with the graph paper and pencil, ground off three of the original brackets and made new ones with some small adjustments. The hole in the bracket at the top of the dump cylinder moved up and forwards 13 mm. The holes in the brackets at the bottom of the dump cylinder moved down 18 mm.

The result:
- Total bucket rotation 139 deg
- Max roll back angle at 150 mm 30 deg
- Max dump angle at 1000 mm 72 deg
- Max dump angle at 1800 mm 39 deg

This geometry matches that of the LA344 as close as I can get it. It does put the pivot points closer to being in line at full curl and full dump than I would have expected before getting started on this project, but it appears to work for the LA344. If it turns into a problem, there's always the grinder. I won't know now until I can try it.

Next step - finish welding the bits I tacked in place then onto the SSQA and bucket.

 

[Paul Allwood]

A little more progress

After getting the geometry where I think I want it, I've made a SSQA receiver for the front of the loader. I could have bought some bits and saved myself a heap of time, but I don't reckon it's the same as making it myself.

Turns out I'm really bad at keeping things straight when I weld them. There was enough warping from end to end of the assembly that I cut and re-welded the main RHS cross tube - slowly and with everything well clamped. I also bolted the smaller piece of RHS to avoid warping.

In a couple of the pics there's a bit that is simulating an attachment showing the pin engagement.

 

[chim]

Beautiful! I'm sure many others here also enjoy tracking your progress.

 

[Paul Allwood]

Beautiful! I'm sure many others here also enjoy tracking your progress.

Thanks Chim

 

[Paul Allwood]

Orange, orange and more orange

Got most of the bits painted yesterday, will hopefully get it all attached to the tractor tomorrow. After that, hoses, connect everything and see if it works. I hope it does.

Then I'll make a brake press to fold the bucket and start on attachments. And make something for ballast - not sure what this will be yet - maybe concrete ?? Open to suggestions.

 

[mdhughes]

Then I'll make a brake press to fold the bucket and start on attachments. And make something for ballast - not sure what this will be yet - maybe concrete ?? Open to suggestions.

There was a guy selling elevator weights and I bought 8 of them and cut them in half. They were 120 pounds full length..

 

[Paul Allwood]

There was a guy selling elevator weights and I bought 8 of them and cut them in half. They were 120 pounds full length..

Thanks

 

[Paul Allwood]

G'day all

The local hydraulic shop started making hoses today for the loader I've been building. The loader is going onto my B7200HSTD. It has a rated hydraulic flowrate of 15 litres/min (4 GPM).

The tech doing the work is making up 1/4" hoses. I questioned him about sizing, specifically whether 1/4" was sufficient. He seemed pretty convinced that it was.

I'm interested in your thoughts. Also interested if you have something I can point to for specifying hose sizes.

Many thanks

Paul

 

[PoTreeBoy]

G'day all

The local hydraulic shop started making hoses today for the loader I've been building. The loader is going onto my B7200HSTD. It has a rated hydraulic flowrate of 15 litres/min (4 GPM).

The tech doing the work is making up 1/4" hoses. I questioned him about sizing, specifically whether 1/4" was sufficient. He seemed pretty convinced that it was.

I'm interested in your thoughts. Also interested if you have something I can point to for specifying hose sizes.

Many thanks

Paul

There are numerous sizing references available by Googling. Here's one posted by @TheOldHokie some time ago.

Hydraulic connectors on a BX2380 or in general.

I have a kind of stupid question about these connectors. I have the BX2380 and want to learn a bit more about the hydraulic connectors. What type are they? Is there a good resource on how to rebuild them or repair them? I am looking into the no warranty period and what I should keep...

www.orangetractortalks.com

Kubota stretches the limits in some areas. For example, my L35 has 11 gpm available for implements but the loader and backhoe are plumbed with 3/8" lines, which is below the chart recommendation. However, the main lines in the pump circuit are 1/2". I think the logic is that the loader and backhoe flows are intermittent, while the supply and power beyond flows are constant. Also, the loader and backhoe are rarely used at full throttle, i.e. full flow rate.

Based on the above, I think 1/4" is appropriate for the valve-to-cylinder lines, but 3/8" on the main lines. What size is the pump discharge? I think the BX loaders are plumbed with 1/4" and they have similar flow as your machine.

Hopefully, @TheOldHokie will respond here.

 

[TheOldHokie]

G'day all

The local hydraulic shop started making hoses today for the loader I've been building. The loader is going onto my B7200HSTD. It has a rated hydraulic flowrate of 15 litres/min (4 GPM).

The tech doing the work is making up 1/4" hoses. I questioned him about sizing, specifically whether 1/4" was sufficient. He seemed pretty convinced that it was.

I'm interested in your thoughts. Also interested if you have something I can point to for specifying hose sizes.

Many thanks

Paul

The number one mistake DIY tractor owners make is oversizing hydraulic hoses. Hose and reservoir sizing charts tend to be oriented towards industrial and agricukturak systems operating at a 100% duty cycle. The concern there is heat buildup due to line friction and constant high pressures.

The main thing to remember here is your tractor has a MAXIMUM flow of 4 GPM at full rated engine RPM. Most of the time its running at lower RPM and flow is much lower - e.g. 2 GPM @ 1800 RPM.

In addition, the vast majority of the time in an open center tractor system the oil is circulating at neutral circuit pressure which is around 100 PSI.

I agree with your hose shop. The 1/4" hoses are rougly equivalent to 1/2" steel tube and adequate for a loader application on that tractor.

Dan

 

[barts]

I'm interested in your thoughts. Also interested if you have something I can point to for specifying hose sizes.

I used 3/8" line (about 4' long) from the pump to the spool valve; 1/4" lines everywhere else on my B5100 w/ a converted B219 loader from a B7100. Like yours, I used a 4 gpm pump, driven from the front PTO.

I am sure I could have used 1/4" line from the pump to the spool valve; I very rarely operate the loader at high engine RPM, and a bit of extra transient pressure drop from the pump to the spool valve (which has an integral relief) doesn't affect anything important. I ordered fittings, hoses and the pump from surpluscenter.com. Unlike the original loader, I added a filter in the return line and added a pressure gauge on the input to the spool valve. The suction line from the reservoir to the pump is 1/2", matching the original; the ~14" long drain line from the filter exit to the reservoir is also 3/8" hose iirc.

 

[Paul Allwood]

The number one mistake DIY tractor owners make is oversizing hydraulic hoses. Hose and reservoir sizing charts tend to be oriented towards industrial and agricukturak systems operating at a 100% duty cycle. The concern there is heat buildup due to line friction and constant high pressures.

The main thing to remember here is your tractor has a MAXIMUM flow of 4 GPM at full rated engine RPM. Most of the time its running at lower RPM and flow is much lower - e.g. 2 GPM @ 1800 RPM.

In addition, the vast majority of the time in an open center tractor system the oil is circulating at neutral circuit pressure which is around 100 PSI.

I agree with your hose shop. The 1/4" hoses are rougly equivalent to 1/2" steel tube and adequate for a loader application on that tractor.

Dan

Many thanks Dan, really appreciated.

 

[Paul Allwood]

I used 3/8" line (about 4' long) from the pump to the spool valve; 1/4" lines everywhere else on my B5100 w/ a converted B219 loader from a B7100. Like yours, I used a 4 gpm pump, driven from the front PTO.

I am sure I could have used 1/4" line from the pump to the spool valve; I very rarely operate the loader at high engine RPM, and a bit of extra transient pressure drop from the pump to the spool valve (which has an integral relief) doesn't affect anything important. I ordered fittings, hoses and the pump from surpluscenter.com. Unlike the original loader, I added a filter in the return line and added a pressure gauge on the input to the spool valve. The suction line from the reservoir to the pump is 1/2", matching the original; the ~14" long drain line from the filter exit to the reservoir is also 3/8" hose iirc.

Many thanks Barts. Did you also build your own loader ?

 

[Paul Allwood]

There are numerous sizing references available by Googling. Here's one posted by @TheOldHokie some time ago.

Hydraulic connectors on a BX2380 or in general.

I have a kind of stupid question about these connectors. I have the BX2380 and want to learn a bit more about the hydraulic connectors. What type are they? Is there a good resource on how to rebuild them or repair them? I am looking into the no warranty period and what I should keep...

www.orangetractortalks.com

Kubota stretches the limits in some areas. For example, my L35 has 11 gpm available for implements but the loader and backhoe are plumbed with 3/8" lines, which is below the chart recommendation. However, the main lines in the pump circuit are 1/2". I think the logic is that the loader and backhoe flows are intermittent, while the supply and power beyond flows are constant. Also, the loader and backhoe are rarely used at full throttle, i.e. full flow rate.

Based on the above, I think 1/4" is appropriate for the valve-to-cylinder lines, but 3/8" on the main lines. What size is the pump discharge? I think the BX loaders are plumbed with 1/4" and they have similar flow as your machine.

Hopefully, @TheOldHokie will respond here.

Many thanks ProTreeBoy. When you say "the main lines", do you mean the line from the hydraulic block to the valve and the line from the valve power beyond port back to the valve ?

And thanks for the link to the sizing chart.