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Corbet
04-17-2013, 10:57 PM
I want to come up with a better solution for the trailer chains on our pop-up (2500lbs). The current chains are too short, too small, and attached with a single small bolt. If I ever had a coupler failure a chain failure would only follow almost instantly:eek:

Pic below is my M101a set up. I like this and want to do something similar. Any ideas on how to duplicate the chain connections to the trailer frame.

Corbet
04-17-2013, 11:00 PM
Visited a few places today looking for ideas. At Fastenal I came up with these two possible solutions. Bolt these on, one on each side, through frame rail of trailer. Then use chain same set up as M101a pictured above

Corbet
04-17-2013, 11:03 PM
Next up, basically a small u-bolt. Again drill through frame rail and use one on each side. I would not need to use the threaded connector links with these. Just loop a chain ling through.

Corbet
04-17-2013, 11:06 PM
interesting little piece of hardware here. But I could not find a clevis or similar item to connect through the hole. These did not have any strength rating on them but looked plenty strong for the task. Definitely a step forward over the stock chains anyway.

Corbet
04-17-2013, 11:10 PM
I'm going to do some web searching to see what else I can find. But any thoughts or ideas are welcomed.

DaveInDenver
04-18-2013, 06:36 AM
The piece of hardware in your last photo is called a shouldered lower link pin. Those are the pins used on tractor 3-point hitches, so a farm supply will have all sorts of them in different sizes. Something to think about is the these fit into a ball at the end of the lower link bars and that little hole is to hold a lynch pin, not really designed to see much force. I wouldn't trust it for safety connection if you bolt through the eye.

You can kinda see how they work here, lower left of the photo.

http://www.mytractorforum.com/attachment.php?attachmentid=94387&stc=1&thumb=1&d=1267289559

The first photo is what's called an eye nut. It's designed as a lifting point, so they are rated for a roughly similar use. If you back that with a grade 8 bolt with a thick washer it should be safe. Rating depends on size, but a 1/2" heavy duty steel carries a WLL of 3,600 lbs and a 5/8 a WLL of 5,800 lbs. Bear in mind that weight is along its axis with the bolt in tension, if you rotate the load to put the bolt in shear it might be different.

What might be better is a swiveling hoist eye, similar to the lifting eye nut but can move through a range of motion. Added complexity and cost, but the rating remains the same regardless of how you load it.

http://www.angelfire.com/biz7/fleximate/images/SwivelLiftingpoints.jpg

You could just use a standard shoulder eye bolt (or sometimes referred to as a turnbuckle eye bolt).

http://image.made-in-china.com/2f0j00zMkTCJenfbGP/Shoulder-Type-Machinery-Eye-Bolts.jpg

Or the various tie-down tabs.

http://www.towshop.com/store/pc/catalog/small_ring_web_538_detail.jpg http://www.towshop.com/store/pc/catalog/eazliftforweb_0043-1_371_detail.gif

How about bolting or welding on a swivel tab.

http://images2.mcmaster.com/Contents/gfx/large/31665t43p1l.png?ver=15332683

DaveInDenver
04-18-2013, 07:03 AM
How about a variation on an engine lifting plate?

http://www.tdperformance.com/cache/ex_q75_w500_h500_images_ePIM_original_4151.jpg

http://static.summitracing.com/global/images/prod/large/sum-g1015.jpg

Corbet
04-18-2013, 07:25 AM
I like the hoist ring idea and thought of that, but too much money. I think I'm liking the wire rope clamp idea the most, as I can eliminate the threaded link which is a weak point in the system. I did find some that were forged and not malleable. Not sure if that part applies to the u-bolt section and it it would even matter?

5/16" chain, grade 70 is the size I'll probably use as it will work well with some gated hooks I found for the vehicle side. Maybe I'm just completely over thinking this and should just bolt the chain on with a grade 8 and big washer? I have a tendency to do that sometimes.

Threaded link I don't want to use if possible.

gahi
04-18-2013, 07:38 AM
This is the factory setup on my car hauler

DaveInDenver
04-18-2013, 08:03 AM
Gary, is that the way the OEM made it? In that configuration those lynch pins are fuses.

Instead of cannibalizing a rope clamp what about just using a u-bolt. You can get those graded AFAIK.

They do make chain bolt for bolting a link directly, I'd check with trailer and boating places.

http://www.smartmarine.co.nz/images/products/large/8021691_trojan_trailer_safety_chain_bolt_kit.jpg

If I was you I'd probably just weld (or maybe bolt and weld) an eye to the trailer frame.

Maybe like this:

http://www.unitex.org/site/catalogue/5000/images/5015.jpg

Then use a chain shackle to connect the chains to it. I don't trust those quick links and these are supposed to be /safety/ chains afterall.

http://www.1st-chainsupply.com/images/Attachments/misc/spchainsh.jpg

gahi
04-18-2013, 08:06 AM
Yes. That's the way it was built. Its a PJ trailer

wesintl
04-18-2013, 08:13 AM
In that configuration those lynch pins are fuses.
.

I don't think so. The shear strength of lynch pins depending on size is anywhere from 12-13k to 28K +

DaveInDenver
04-18-2013, 08:25 AM
I don't think so. The shear strength of lynch pins depending on size is anywhere from 12-13k to 28K +
True, but remember that pins are rated for double shear yield. It's better than a bolt here, but some being half round do give up cross section. I was just wondering if that was original, it works but seems to me to leave some room for end user error if someone does not replace them with with equivalent.

Corbet
04-18-2013, 08:37 AM
I like the pin system on the car hauler even tough Dave does not :o Gives you the ability to adjust the chain length for different vehicles. I always need extra chain for my 4x4 labs bumper as the chain eyelets are up under / behind the bumper.

I also like those chain bolts Dave posted. What sucks down here are my retail resources are so limited. Ordering two speciality bolts online is not cost effective and it pains me to do it. There is one trailer place in the county. See if I can get over there tomorrow.

rover67
04-18-2013, 08:42 AM
True, but remember that pins are rated for double shear yield. It's better than a bolt here, but some being half round do give up cross section. I was just wondering if that was original, it works but seems to me to leave some room for end user error if someone does not replace them with with equivalent.

It also seems that while there would be some shear load on the pins most of the force would go into bending the link over in the event of that chain being yanked.

DaveInDenver
04-18-2013, 08:44 AM
I like the pin system on the car hauler even tough Dave does not :o Gives you the ability to adjust the chain length for different vehicles. I always need extra chain for my 4x4 labs bumper as the chain eyelets are up under / behind the bumper.
I'll clarify, the way they did that is fine. If you do it yourself you need to make sure the slot is cut cleanly and just large enough for the link to fit through. If it's a hole, the pin will bend or pull through before the chain link bends. Also, I thought the OEM would put them on leashes so someone can't put undersized fastener in for lost pins.

OilHammer
04-19-2013, 10:46 AM
Sometimes I think you guys just like over complicating things for the sport of it.
While not as clean, why not just take the easy route and loop two chains through the "A" of the tonge and connect them via rated hardware? Or are we assuming the tongue triangulation is too far away or ripped off in the accident completely?

I'm not sure why you guys are dogging on quick links, some of them ARE rated and are even supplied by Reese as a product intended for towing.
A rated one:
http://www.homedepot.com/p/Lehigh-3500-lb-x-3-8-in-x-3-1-4-in-Stainless-Steel-Quick-Link-7443S-6/100299638

You rip through two of those, and you likely rolled your truck in the process.
Or, if you REALLY want sturdy, use these: http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=102174&catalogId=10001&langId=-1&storeId=11151&storeNum=50304&subdeptNum=50331&classNum=50333

You can find those cheaper than west marine, but good lord, 6,500# per link should suffice.

Corbet
04-19-2013, 11:00 AM
Sometimes I think you guys just like over complicating things for the sport of it.

I'm not sure why you guys are dogging on quick links, some of them ARE rated and are even supplied by Reese as a product intended for towing.


Oh, I agree. For me I guess is the challenge is to fabricate something that looks super clean and is still as strong or stronger than the standard solutions. So yes there is some sport to it:D

I used the quick links on my other trailer (3/8") and I'm not against using them, but on this project I'm trying not to. My only complaint is that for any given size the quick link is rated at about half that of the chain(grade 70). I plan to use 5/16" chain so the quick link in this case is rated at 2200lbs. That's a little under the gross trailer weight but with two in the system I should be good if I go that way. Anything will be better than the 1/8" chain that came on the trailer:eek: And in addition to the lack of strength my current chains are just too short.

OilHammer
04-19-2013, 01:21 PM
Oh, well if we are sporting...

http://www.fmcsa.dot.gov/rules-regulations/administration/fmcsr/fmcsrruletext.aspx?reg=393.70

wesintl
04-19-2013, 04:56 PM
I'm not sure why you guys are dogging on quick links, some of them ARE rated and are even supplied by Reese as a product intended for towing.
A rated one:
http://www.homedepot.com/p/Lehigh-3500-lb-x-3-8-in-x-3-1-4-in-Stainless-Steel-Quick-Link-7443S-6/100299638

that seems kinda chinsy :D

Corbet
04-24-2013, 04:54 PM
Well I ended up just bolting (3/8" grade 8) up the chains in the OEM location. Kept it simple. No threaded links needed. 5/16" grade 70 is plenty overkill for my application:thumb: