Forum › Forums › Site Questions and Help and Features › Backhoe sub frame thread
- This topic has 35 replies, 5 voices, and was last updated 12 years ago by Len10.
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January 29, 2012 at 7:48 pm #30503
Is it me or is the Backhoe Sub Frame thread all screwed up?
Is this site infected again?
Hal??
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January 29, 2012 at 8:35 pm #34136
Well this is another fine mess you've gotten us into, Ollie!
There's definitely a problem of some sort there, but I have no idea why, of course. I suppose Hal will fix it. He must get sick of having to pick up after us…
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January 29, 2012 at 9:03 pm #34137
I went to post a simple text response and that mess is what displayed. This site needs help. I am not going to waste anymore time on it.
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January 29, 2012 at 9:44 pm #34138
I am planning on doing several videos of dozer steering clutch/brake issues augmented with still pics. It doesn't appear at this point that I can do it on this site.
I'm sure Hal is probably up to his proverbial butt in alligators, but a word from him would be appropriate now.
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January 29, 2012 at 11:32 pm #34140
Starting where I left off before the SNAFU:“Another reason for reinforcing the FEL subframe are two cutouts on the rectangular tube of the subframe. One is shown in the included picture. The other is on the inner side of the same tube toward the rear. As you can see from the picture, it is very roughly cut. It came directly from the factory this way. Does anyone know what they could be for?”
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January 30, 2012 at 6:43 am #34141
What's wrong with this thread? Why are there two of them? Does this site offer instructions anywhere about uploading photos. I tried to help this thread recently and expressed my confusion about photos. Result: no answer and now we have duplicate threads.
Why is CTOA so difficult?
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January 30, 2012 at 6:45 am #34142
First of all Len, I think you're doing a great job.
As for the cut-outs, I can only imagine they were made for access. No other reason. I would fish plate over. And they greatly compromise the section modulus strength of the tube.
Steve,
The other thread died on the vine, no way to post to it. When I started this thread it was an inquiry, and not meant as a continuance because of the category it's in. However, as far as I'm concerned it can continue here, or Hal can fix the site and move it where it belongs.
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January 31, 2012 at 10:40 pm #34148
Thanks Bob for the encouragement. I'll post some pictures of the subframe after I start fabricating the parts.
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April 30, 2012 at 10:30 pm #34479
I finally cut most of the parts for the subframe. Thanks Rich for the tip about the Longevity plasma cutter. Due to my inexperience with plasma cutting, I spent a lot of time with my angle grinder. I'll post pictures as soon as the parts are welded together.
In the mean time, does anyone have a good source for hex bolts? Due to the modifications I made the u bolts that attach the ROP are not long enough. I want to replace them with hex bolts (1/2-13 x 11 inches and 1/2-13 x 8 inches, grade 8, yellow zinc). Similar metric sizes would be OK too. The only source I can find that sells zinc plated bolts that long charges $15-20 per bolt. I found many suppliers that charge about $2 per bolt, but they are not yellow zinc plated (although they are grade 8).
When I'm ready to post pictures should I continue with this thread even though it's in the wrong category (the original thread became corrupted)?
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May 1, 2012 at 6:39 am #34480
You can start a new thread if you want I guess.
I'm surprized you found yellow zinc plated bolts at all because most all zinc plated products are silver colored. I think you will have better luck searching for di-chromate plated or cadmium “cad” plated fasteners, both of which are yellow-ish gold in color.
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May 1, 2012 at 9:32 pm #34481
I think most bolt suppliers use the term “yellow zinc” to refer to zinc plating followed by a chromate conversion coating. My understanding is zinc plated bolts always have a chromate conversion coating since zinc plating alone would corrode quickly when exposed to moisture. A zinc coating that appears “silver colored” is referred to as “clear zinc” or “blue zinc” and is less corrosion resistant than yellow zinc. I would be happy with a clear zinc plated bolt since I won't be using my tractor anywhere salt water.
I don't think cadmium plated fasteners are readily available anymore because of the toxicity of cadmium. Even the type of chromate conversion coating used has changed because of the toxicity of hexavalent chromate. The newer chromates are less toxic, but also less corrosion resistant. At least that is my rudimentary understanding.
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May 1, 2012 at 9:57 pm #34482
If'n ya wants corrosion resistance, just use hot-dipped galvanized fasteners. Much thicker coating and much more resistant to rusting.
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May 1, 2012 at 10:59 pm #34483
Just get the black carburized grade 8 bolts and coat them liberally with Cold Galvanizing Compound (spray can) before and after assembly, then finish paint with two coats. I have used this at sea for years.
You can get the bolts hot dipped also – for a nominal fee.
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May 2, 2012 at 1:52 am #34484
Yes, you can get the bolts hot-dipped, but you'll need to purchase ready-made HDG nuts for them – they have to be slightly oversize to accommodate the thickness of the hot dip galvanizing on the bolt threads. Try to put a regular nut on an HDG bolt and you'll quickly see what I'm talking about. You can guess how I learned this, I'm sure.
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May 2, 2012 at 8:55 pm #34492
My understanding is that grade 8 bolts should not be hot-dipped galvanized secondary to the risk of hydrogen embrittlement. I'm not sure how critical the use of grade 8 bolts is, but I want to over engineer the sub frame. I have no experience in structural engineering, so I'm basically flying by the seat of my pants.
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May 2, 2012 at 10:29 pm #34496
Galvanizing temps shouldn't be hot enough to cause hydrogen migration into the grain boundaries of the steel, I wouldn't think. But I'm NOT a metallurgist.
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May 3, 2012 at 5:17 pm #34501
From what I know, hot-dip galvanizing of grade 8 bolts is not a problem.
The question I was going to ask but has already been raised is: Why use grade 8 bolts? No real reason in this application as far as I'm concerned. Grade 5 is quite sufficient as you can see, and this or it's metric equivalent is used by most equipment manufacturers except in very special applications.
See ASTM bolt properties here (probably not what you expected).
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May 3, 2012 at 6:58 pm #34504
I know it's just symantics, but you say that you want to “over-engineer” the sub frame. In order to do that, you must first engineer it, and then exceed those specifications. I think what you really meant was that you want to “over-build” it.
In any event, here is some useful info that many of us take for granted in understanding.
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May 3, 2012 at 9:54 pm #34510
Here is a good explanation for which high strength bolts can be hot-dip galvanized. According to the table at the bottom, grade 8 bolt can't be galvanized.
Bob, you're absolutely right, I should have used the term “over-build.” Equipment manufacturers engineer their products so they know or should know what size and grade of bolts are appropriate to use. Since I don't have that knowlege I would rather spend a little more a bolt that has 25% higher tensile strength.
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May 3, 2012 at 11:39 pm #34513
OK, but I've personally witnessed hot-dipped galvanized grade 8 bolts and nuts. Someone else broke the rules, not me.
I think you are doing a great job on the sub frame and if it were me, I'd just go with grade 5 zinc coated and paint it. If you have issues with clamping power you can use fine threads. It's not like you will be using it on an ocean beach all year long. Or will you?
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May 4, 2012 at 2:48 pm #34520
I might just go with grade 5.
As for the ocean beach…..not a chance. I won't even use the tractor in the rain. Not even a drizzle. Furthermore by car hasn't seen the inside of my garage since I bought the tractor. My wife's car hasn't seen the inside either…something she's not too happy about!
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May 5, 2012 at 10:17 am #34524
Sounds like time for a carport or three car garage.
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May 5, 2012 at 12:14 pm #34525
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May 6, 2012 at 1:22 pm #34533
That's hilarious!
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May 15, 2012 at 9:11 pm #34605
Some of the sub frame parts are cut and welded. The hole shown in the picture is suppose to have a 1-1/8 in. diameter.
Due to runout the hole is larger and the pin that will be used to attach the backhoe fits too loosely. I plan to enlarge the hole and then use a category 3 to 2 lift arm reduction bushing (1-7/16 in. OD and a 1-1/8 in. ID). The reinforcing rings (one on each side of the plate) make the thickness of the steel 1-5/8 in. How much smaller should the diameter of the hole be, as compared to the OD of the bushing, if I install it with a shop press?
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July 17, 2012 at 10:09 pm #34888
I finally made some progress on the subframe. In case anyone's interested, the included picture shows the parts that make up the portion that attaches to the tractor. The yellow arrows point to pieces that belong to the loader subframe. The only modification I made to the loader subframe was to weld 1/4 inch plate to the sides of tube near the back for reinforcement.
The 2 large brackets are made of 5/8 inch plate. They slip over the axle housing and attach to the tractor at multiple points. I'll show how they attach in a subsequent post. The 9 inch wide plate bolts to these brackets, runs under the tractor and bolts to where the drawbar would normally mount.
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July 17, 2012 at 10:17 pm #34889
Below is the 9 inch plate shown mounted under the tractor. The hydraulic oil plug is still accessible through the hole.
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July 17, 2012 at 10:23 pm #34890
The 9 inch plate shown from another angle.
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July 17, 2012 at 10:29 pm #34891
A picture from the rear of the tractor showing the mounted bracket. The bracket is bolted to the axle, ROP, front loader subframe, fender bracket, and 9 inch plate. Now I need to make some modifications to the backhoe before I can mount it.
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July 18, 2012 at 1:35 am #34892
That's looking great, Len!
I'd suggest making an extended drain tube for the hydraulic, so when you pull the plug the stuff doesn't just run all over the topside of that nice new bracket. I should think that would work, anyway.
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July 19, 2012 at 7:42 am #34900
Thanks Rich for the input. If there's any interest, I can post pictures after I modify the backhoe.
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July 20, 2012 at 1:03 am #34903
Very nice work Len.
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August 10, 2012 at 9:23 pm #34975
Thanks Bob.
I had to bend 1/2 x 9 inch flat bar to get a 1 inch offset as part of the modification to the backhoe. As I don't have an acetylene torch, I needed to do the bend cold. I searched the web for help, but came up empty. I did bend some 1/2 x 3 inch bar as can be seen in the previous photos. I made a press using some old lumber from a defunct swing set and a 4 ton bottle jack. (see 3rd photo). If creaked a lot, but held up. For the wider bar, I made a bigger press and used a 20 ton jack. Although I used much larger timbers and more lag bolts, it wasn't strong enough. I had to reinforce it with angle iron (left over from the tractor crates). It's not very pretty, but it worked (1st photo) just barely (see bent bolt in 2nd photo).
I don't think the next smaller size jack (12 tons at Harbor Freight) would work. I had to really force the handle on the 20 ton jack.
The wood in the last photo was charred by my plasma cutter. Plasma cutting on a wood bench is probably not a smart thing to do.
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November 11, 2012 at 10:37 am #35245
I finally finished the subframe. The pictures below show a test fit. The unpainted steel is the portion that gets permanently mounted to the backhoe. The other picture shows the painted components that get attached to the backhoe
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November 11, 2012 at 10:45 am #35246
The next 2 pictures show the backhoe attached with the wheel off for clarity. The backhoe can be detached by removing the 2 upper 1 1/2 inch bolts and then lifting the backhoe to unhook the lower 2 pins.
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November 11, 2012 at 10:55 am #35247
The next 2 pictures show the final product. If anyone is interested I will be posting more pictures and a more detailed explanation in the week or two on Tractor by Net.
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