spring assemblage settings?

[hugo]

Hi,

I had my track tension spring unit dammaged when my track was thrown off.
The bolt is bent.
It was a nice struggle to get it all loose. Those nuts don't like a bent bolt.

When i was sepparating the unit the bolts were in the position of the red arrow.



I never did get it. In my opinion this thing was not able to plumage (or bounce) like it is supposed to.

so i got into my books and came with this setting. Is this correct?



I have read that i need to tight the big spring about 4 inch. is this correct?






Ps how about my welded cast iron front cap!!! Not bad for a amateur!!! And self learning welder!
2 small pieces were broken of bij impact (track trown)

hugo

[jdemaris]

Hi,

I had my track tension spring unit dammaged when my track was thrown off.
The bolt is bent.

I hope that's not a standard piece of threaded rod you're sticking in there. That thing gets a lot of tension on it when assembled, and is dangerous. Putting a grade 2 or grade 5 threaded rod in there would make it a time-bomb.

[hugo]

I hope that's not a standard piece of threaded rod you're sticking in there. That thing gets a lot of tension on it when assembled, and is dangerous. Putting a grade 2 or grade 5 threaded rod in there would make it a time-bomb.

Thanks for the warning!!!

I got a M 24 (0.944879 inch. About 15/16") grade 8.8 steel. That is an european standard.
We have a lot of quality grades.
4.8 quality.
8.8 quality (that is used for industial use)
9.8
12.8

I found that 8.8 has a pulling strengt of 800 N/MM2

Is it safe enough?

Thanks, Hugo

[hugo]

Hi

I have the 'bolt' analysed for the pulling force.

(I had to ask it to my lovely girlfrend who is a student at an university.)

Its about 200 Kn (very safely calculated

Thats 44961.79 pound-force lbf

Is it safe??
considdering the spring is old.
Or can i adjust it to 15 7/8 '' (give the track spring a little less tension)

thanks, hugo

[Maynah13]

Just thought I'd jump in with a handy bolt grade chart...

http://dave-s.com/Portfolio/ref/BoltProp.htm

[jdemaris]

Hi

I have the 'bolt' analysed for the pulling force.

(I had to ask it to my lovely girlfrend who is a student at an university.)

Its about 200 Kn (very safely calculated

Thats 44961.79 pound-force lbf

Is it safe??
considdering the spring is old.
Or can i adjust it to 15 7/8 '' (give the track spring a little less tension)

thanks, hugo

I'm not a metal expert. I CAN tell you that the original bolts bent and broke when hit hard. We had to change quite a few in 350s. I hated putting the new bolts in, with the big press. Once assembled, and you hold that thing in your hands -it could kill you - if pointed at you and bolt broke. I had one once put a hole through a concrete block wall. I put it in the same category as working on big split rim truck wheel/tire. Once installed in the crawler - it can't hurt anyody. If it breaks - just makes the track ultra tight.

The original Deere bolts were billet-steel, axle-grade ASTM A17. Probably had a tensile strength of 80,000 lbs and a yield of 50,000 PSI. 1" diameter bolt by 21". I think the new bolts from Deere are equivlent to a grade 8 or 9 - but Deere isn't very good about giving exact specs. If you've got a metric grade of 10.9 or up, it's probably fine. I only mentioned the threaded rod because GOOD threaded rod is usually special order item - and local stuff is usually no better than grade 2. I order a lot of B7 rod for track adjusters.

[Maynah13]

According to the Bolt Reference chart in the link I posted above, a Euro grade 8.8 bolt is equal to a US grade 5. That's rated at 91,000 psi and a tensile of 113,784 psi

I tried to look up the A17 grade, but it doesn't seem to exist anymore. The A17D grade listed on the jdparts specs doesn't even show on a Google search.

When it comes to safety, you can't be too careful, but if you trust the information available, then he's okay. Naturally, if he can go to a 10.5, that's even better. Not being able to find a definitive spec on the original makes me want to be extra cautious.

Robert

[jdemaris]

According to the Bolt Reference chart in the link I posted above, a Euro grade 8.8 bolt is equal to a US grade 5. That's rated at 91,000 psi and a tensile of 113,784 psi

I tried to look up the A17 grade, but it doesn't seem to exist anymore. The A17D grade listed on the jdparts specs doesn't even show on a Google search.

When it comes to safety, you can't be too careful, but if you trust the information available, then he's okay. Naturally, if he can go to a 10.5, that's even better. Not being able to find a definitive spec on the original makes me want to be extra cautious.

Robert

A17 was replaced a long time ago - first to A273, and then ASTM A711. But that only gives you a range that that alloy falls into.

I've got to rummage around my shop and find an old bolt and look closely to see if Deere even has marks on it. I have several that broke, and I saved as big punches. They're a pretty nice hunk of steel, similar to the Deere load& depth shafts used in farm tractors.

Considering that Deere now charges $100 each for those bolts, I'd like to think they've got some good hardened alloy steel in them. I know a place that sells those bolts in 10.9 grade for $18 each (1" diameter, 21" long, and 6" of thread). So, either Deere is making a big mark-up, or their bolt is even a better grade.

[Maynah13]

It'd be interesting to see what markings were on one. I wouldn't necessarily go by cost, though. Mother Deere wants $220.00 for the oil cup on the air cleaner of my 450B that I can get for $27.50 elsewhere

If my math is good, then 113,784 psi turns into 784 N/mm2. That would be a grade 5 US or 8.8 Metric. This is about 50 tons of force per inch, if any of this helps.

Anyway, no argument here to err on the safe side, just gathering knowledge in case I have to replace one myself at some time.

Robert

[jdemaris]

I wouldn't necessarily go by cost, though. Mother Deere wants $220.00 for the oil cup on the air cleaner of my 450B that I can get for $27.50 elsewhere

I don't know what the heck is going on with Deere parts and prices. Deere used to be very good about not having extreme markups on prices for parts they bought elsehwere. But now? I just priced a new Cessna gear pump - same Cessna # as used in 350 and 450 crawlers, Case and Ford backhoes, etc. $800 or more from Deere and $350 something, over the counter from Case. Same pump ! I don't understand how that can happen, unless Deere no longer wants customers with old machines?

So yeah, I understand that price does not always reflect supreme quality.