Someone familiar with tractor 3 point "in general?"

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67Dart273

67Dart273

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So this backhoe I bought is set up for 3 point but that is not how I'm mounting it, and the little Farmall 100 (Super A) doesn't have either 3 point or "fast" or "quick" hitch anyhow.

I've now got the lower pin support frame completed, and what positions the hoe at "top" is what amounts to a 3 point adjustable center (top) link. It came with one, seems to be 15/16 thread, and uses 3/4" dia pins, which fit the hoe. Please don't ask me "what class hitch."

I intended to unscrew either end to see if the tube was threaded further in, but neither will come out. It almost appears that they screwed on the threaded end collar, "bunged up" the threads to make them captive, and then welded the collar to the tube.

This link has to keep the entire hoe from tipping forward / back under heavy work load and jerking, etc

MY QUESTION IS how far out can I safely unscrew these as it needs to be fairly long. Would, say, 1" of thread "inside the tube" be OK?
Below, one of the support arms, 2" very heavy wall square tube, with 1/2x3" flat welded to outer side for added stiffness. Mount plates same material, 1/2x3, drilled together to match, 5/8 bolts. The mounted plate hole as you can see has been sawed open so the pin can drop down, then the outer plate bolted on to retain
IMG_1595cs.JPG

The hoe showing the lower pins which "were" 3 point
IMG_1596cs.JPG

The upper adjustable link attachment, which also "was" the seat bracket. 3/4" pin
IMG_1597cs.JPG

The adjustable upper link, 3/4" pins, 15/16 thread
IMG_1598cs.JPG

Showing the threads and lube? holes. The ends will not come out. Again, the question, do you think the tube is threaded further in, or just the welded collar on end? How much thread do you think makes it "safe?" Seems like the tube must not be threaded...............
IMG_1599cs.JPG


"How it mounts." You back up to it, and jockey to get it aligned. You get close enough to install the PTO pump, and now you have power. Diddle the hydraulics if need be to get the mount pins above the bracket plates. Back on in, Diddle the pins into the slots, and install the retainer plates and bolts.

I've had that part done and so far so good. Tomorrow I need to work on the center / top link
 
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My rule of thumb is 3-5 threads min, but more the better. If I'm putting the link in compression, I'm fine with 2-3 threads. But in tension I want no less than 3 full turns. I haven't found much good guidance for this either though, but I've used my rules of thumb plenty when pushing and pulling a few thousand pounds of slash, snow, dirt, etc and I've yet to fail the top link or impale myself when working in reverse. I also abuse the ever living hell out of my stuff, its ridiculous. If you knew you were going to put a massive load on the link, I would try for no less than 5 threads..

You can buy different length top links too.
Some top links the ends will come out, others they won't. Tractor supply and North 40 both have a few choices of length in stock. Best to measure what you need, then take your tape with you because the lengths advertised on the links are about as useful as hitch classes.

Class rating of hitches make no sense, it's best ignored completely. 3/4 pins are common, that's what my Ford 3000 3cyl uses. They make sleeves to size up/down, but 3/4 is probably the most common anyway.
 
Thank you. I just looked this up. The hoe has 7/8 lower pins and 3/4 top link pins, and "according to a chart" that makes it a "class 1" hitch, for all that's worth, LOL

I think what I'll do is get the anchor point in place for the top link--forward on the tractor, and then figure on cutting and beefing and extending the tube so I can have more "rod" internally. That will help prevent buckling, more threads or not
 
67Dart273 said:
Thank you. I just looked this up. The hoe has 7/8 lower pins and 3/4 top link pins, and "according to a chart" that makes it a "class 1" hitch, for all that's worth, LOL
Click to expand...

Yeah, it's all so confusing because stuff gets advertised as whatever but doesn't always match.
My hitch is considered class 1, but is 3/4 on all three pins.
I've bent the 3/4" plate that the pins are attached to on my box blade when I rammed a snow berm in reverse and it didn't move. I had my top link fully extended to 3 turns engaged to get the back of the box blade to bite in reverse. No issue with the top link.

I bent the **** out of a subsoiler, both the cross arms and the blade, when pulling stumps on a steep hill. Same thing.

So I've overloaded it in both directions and lived to tell the tale.

With your subframe, you should be good. I'd be more worried about the gap at the trans from the previous mod cracking the trans or engine block, but only if you get into moving boulders or digging out black locust stumps or something crazy.
 
67Dart273 said:
So this backhoe I bought is set up for 3 point but that is not how I'm mounting it, and the little Farmall 100 (Super A) doesn't have either 3 point or "fast" or "quick" hitch anyhow.

I've now got the lower pin support frame completed, and what positions the hoe at "top" is what amounts to a 3 point adjustable center (top) link. It came with one, seems to be 15/16 thread, and uses 3/4" dia pins, which fit the hoe. Please don't ask me "what class hitch."

I intended to unscrew either end to see if the tube was threaded further in, but neither will come out. It almost appears that they screwed on the threaded end collar, "bunged up" the threads to make them captive, and then welded the collar to the tube.

This link has to keep the entire hoe from tipping forward / back under heavy work load and jerking, etc

MY QUESTION IS how far out can I safely unscrew these as it needs to be fairly long. Would, say, 1" of thread "inside the tube" be OK?
Below, one of the support arms, 2" very heavy wall square tube, with 1/2x3" flat welded to outer side for added stiffness. Mount plates same material, 1/2x3, drilled together to match, 5/8 bolts. The mounted plate hole as you can see has been sawed open so the pin can drop down, then the outer plate bolted on to retain
View attachment 1715958341
The hoe showing the lower pins which "were" 3 point
View attachment 1715958342
The upper adjustable link attachment, which also "was" the seat bracket. 3/4" pin
View attachment 1715958343
The adjustable upper link, 3/4" pins, 15/16 thread
View attachment 1715958344
Showing the threads and lube? holes. The ends will not come out. Again, the question, do you think the tube is threaded further in, or just the welded collar on end? How much thread do you think makes it "safe?" Seems like the tube must not be threaded...............
View attachment 1715958345

"How it mounts." You back up to it, and jockey to get it aligned. You get close enough to install the PTO pump, and now you have power. Diddle the hydraulics if need be to bet the mount pins above the bracket plates. Back on in, Diddle the pins into the slots, and install lthe retainer plates and bolts.

I've had that part done and so far so good. Tomorrow I need to work on the center / upper link
Click to expand...

To answer your question directly, the threads are only on the welded in collar. Not any deeper. The way you describe the manufacture is pretty spot on. The threads go in after welding but the male threads get boogered after assembly to prevent a user over loosening and injuring themselves.
 
Phreakish said:
I'd be more worried about the gap at the trans from the previous mod cracking the trans or engine block, but only if you get into moving boulders or digging out black locust stumps or something crazy.
Click to expand...

Ok you lost me here........? what previous mod?
 
67Dart273 said:
Ok you lost me here........? what previous mod?
Click to expand...

I thought I remembered in another thread you described the tractor having been previously modified to use a different clutch or starter or something and there was a gap left between the engine and trans? Maybe that was someone else? Stuff tends to blend together.
 
LOL that was Dad's old '28 Farmall "Regular" that I grew up with. It has a frame, and a factory space between the bell and gearbox. He modified the coupling down in there, and added a flywheel to install a starter.

010_8s-jpg-jpg.jpg


My tractor is a "100" just a modernized "Super A" and about a step and a half bigger than a Cub
 
On that one, I am almost certain the tube is not threaded. The diameter of the tube on the inside of the collars looks to be too big an ID to support the 15/16 threads.
 
67Dart273 said:
LOL that was Dad's old '28 Farmall "Regular" that I grew up with. It has a frame, and a factory space between the bell and gearbox. He modified the coupling down in there, and added a flywheel to install a starter.

View attachment 1715958358

My tractor is a "100" just a modernized "Super A" and about a step and a half bigger than a Cub
Click to expand...

LOL, now I get it. I skimmed over some of the other thread. Gets me in trouble every time.
 
On any thread the general rule of thumb for engagement for maximum strength is 1-1/2 X thread diameter.
 
That lower mounting set-up where the drawbar goes could be tough on the rear 'bullgear' castings.
They will crack.
Been there.
 
TT5.9mag said:
On any thread the general rule of thumb for engagement for maximum strength is 1-1/2 X thread diameter.
Click to expand...

True. High strength fastener design guidelines tend to agree. My 3-5 threads is based on pitch tolerance studies that show that only approx 3-5 threads of most fasteners actually engage mating surfaces. The longer a threaded engagement, the more likely the condition becomes.
This is one of the major reasons for torque to yield bolts. It gives a greater chance of engaging more threads by stretching the faster into as much engagement as possible.
It also assumes axial load, and no shear. I would definitely stay at 1.5-2x diameter if any shear is present.

In practice, I've never had a design fail in axial tension when following the 3-5 thread rule with coarse threads in like materials. I double it if threading into aluminum or titanium though. 2.5x in magnesium, and like I said: if shear is present, go for no less than 1x diameter (1.5-2x preferred).
 
70 Buster 340 said:
That lower mounting set-up where the drawbar goes could be tough on the rear 'bullgear' castings.
They will crack.
Been there.
Click to expand...
I'm still thinking of "how to beef that. This tractor is really set up poorly for that purpose. There's a huge boss up on top of and behind the gearbox, but there's a removable piece behind it which might be dangerous to put vertical weight upon. The right side has a mount point that could be used I think.

This will not be used for digging much, and likely "lightly used." I bought it more "thinking" to lift stuff like outboards. I visualize the bucket being "off it" most the time.........
 
70 Buster 340 said:
That lower mounting set-up where the drawbar goes could be tough on the rear 'bullgear' castings.
They will crack.
Been there.
Click to expand...
What have you had, by the way, in similar tractors, and what equipment and used caused the damage?
 
Seen it on Cubs, 100 and a 130 I had.
Cub had the 'one arm' loader, 100 was busted when I got it an the 130 had a home made 3 point with a super big and heavy grader blade and dual rear wheels.
Sometimes they crack right at the bolt boss and sometimes they'll crack where the brake rod goes in to the bullgear housing.
 
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70 Buster 340 said:
Seen it on Cubs, 100 and a 130 I had.
Cub had the 'one arm' loader, 100 was busted when I got it an the 130 had a super big and heavy grader blade and dual rear wheels.
Sometimes they crack right at the bolt boss and sometimes they'll crack where the brake rod goes in to the bullgear housing.
Click to expand...
Thanks. Sounds like the 130 was "heavily abused."
 
Phreakish said:
True. High strength fastener design guidelines tend to agree. My 3-5 threads is based on pitch tolerance studies that show that only approx 3-5 threads of most fasteners actually engage mating surfaces. The longer a threaded engagement, the more likely the condition becomes.
This is one of the major reasons for torque to yield bolts. It gives a greater chance of engaging more threads by stretching the faster into as much engagement as possible.
It also assumes axial load, and no shear. I would definitely stay at 1.5-2x diameter if any shear is present.

In practice, I've never had a design fail in axial tension when following the 3-5 thread rule with coarse threads in like materials. I double it if threading into aluminum or titanium though. 2.5x in magnesium, and like I said: if shear is present, go for no less than 1x diameter (1.5-2x preferred).
Click to expand...
I completely agree with your line of thinking here. And I’ll add one thing, when I design something, (although it’s impossible in some circumstances), I try to eliminate any possibility of the connection failing in shear. At the very least mount in double shear.
 
TT5.9mag said:
I completely agree with your li e of thinking here. And I’ll add one thing, when I design something, (although it’s impossible in some circumstances), I try to eliminate any possibility of the connection failing in shear. At the very least mount in double shear.
Click to expand...

I was at an event over the weekend that required attendees to use very low folding chairs. Mine failed and is now permanently reclined because they used aluminum rivets in single shear.
I cannot understate my hatred of single-shear connections, LOL.
 
Phreakish said:
I was at an event over the weekend that required attendees to use very low folding chairs. Mine failed and is now permanently reclined because they used aluminum rivets in single shear.
I cannot understate my hatred of single-shear connections, LOL.
Click to expand...
Ok that’s funny. I am the same way. My fabrication background comes from building off road race trucks. At SEMA last year there were more trucks than anything else outside. I couldn’t help but pick out every dangerous single shear mount for steering and suspension.
 
TT5.9mag said:
Ok that’s funny. I am the same way. My fabrication background comes from building off road race trucks. At SEMA last year there were more trucks than anything else outside. I couldn’t help but pick out every dangerous single shear mount for steering and suspension.
Click to expand...

It's spooky what some people think is good enough.

My Ford 3000 came with a loader attached, but the front end is super skimpy. I've broken 3 spindles already. One because I didn't appreciate just how skimpy it was and was trying to back up with the wheel turned hard over while lifting a 2500lbs log. The other two were just from the front end being loaded a little goofy while maneuvering with a modest load in the bucket. Wish I could find a tractor junkyard to rob a 3400 front end from!
 
I admit this little gal is "pretty light." I've actually had the rear wheels off the ground with the loader trying to move something, but generally I'm "fairly" careful I think. I've even seen pictures/ videos of several of the "compact" tractors of various kinds broke in half.
 
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