Rolok size

Topic: Rolok size (Read 1052 times) previous topic - next topic

Rolok size

June 12, 2015, 01:42:21 pm

I called FT parts to buy some roloks and was told they have none and there is none available any where. FT is using huck bolts that require tool to install.
So I am looking for a source and or a similar product as I do not want to cut holes to install bolt and backer.

Re: Rolok size

Reply #1 – June 12, 2015, 01:58:17 pm

John,

OK-- my $.02:

I do not like anything that concentrates the force on only a small area of one wall (the interior wall) of a (maybe weakened by rust) box beam.

Cutting a hole in the fiberglass bottom and using a waterproof plug (if only a few), or remove a 6" piece of the fiberglass floor if all need reworking. is really pretty easy. The fiberglass is quite thin and a hole saw makes quick work of it.

This also allows you to use a proper backing. To me, a proper backing is 1/8" steel, 1 1/2" "tall" and 3" or so long. This spreads the load to the two horizontal parts of the box beam.

Re: Rolok size

Reply #2 – June 12, 2015, 06:32:51 pm

Let me post this for anyone going to Foretravel-- would appreciate your follow up:

Bulkhead Question

I have a question that came up in doing the inspection on the Crystal Ship yesterday.

Both bulkheads had been redone. Assume Wayne Musser did it, as it was Huck Bolted, not through bolted.

Also, the fiberglass 6" or so forward of the bulkhead and all the way across the bulkhead had been removed to give access, and a replacement panel properly screwed in place and waterproofed.

In the past, people believed that the Foretravel repair just used the Huck Bolts with no backing plate on the inboard side of the box beam. In other words, the force was concentrated on a very small area in the middle of only the inboard wall of a (likely) already structurally compromised box beam. NOT GOOD.

However, if, while he has access to the inner wall of the box beam he uses large "washers" to spread the load, it would be much better structurally. Best "washer" is 1 1/2" tall by 3-4" long 1/8" thick piece of steel with a hole drilled in the middle for the Huck bolt or through bolt. This would spread the compression load on the two vertical walls of the box beam where it should be. If this is what they do, I want to be able to let everyone on the Forum know it, rather than let a misunderstanding continue to send bulkhead repair away from Foretravel.

If you have either seen the "inside" of one of their repairs, of could talk with Wayne or someone at Foretravel, I would appreciate it and it would absolutely be a positive thing for Foretravel.

Thanks.

Brett

Re: Rolok size

Reply #3 – June 12, 2015, 08:17:24 pm

OK, my $0.02 worth. If you don't want to make access to the back side of the tubing from underneath, you can buy full thread bolts, use a long tap, tapping the near and far side. This way, you are not concerned about the load on the far .125" wall but have two walls to hold so are actually .250" in thickness IF there is no rust that has weakened the rectangular tubing. When you torque them down, you are pulling on both walls.

Without putting a nut on the far side, the torque required is much less for grade 5 or stainless fasteners compared to grade 8. If you put a nylock and washer on the far side, it's not an issue.

Best would be hot dipped galvanized or stainless in 3/8". Here is a site with stainless fasteners: Hex Tap Bolt 3/8"-16 18-8 Stainless Steel Try Fastenal to see what they can get.

To me, 316 stainless would be a slightly better choice over 18-8 as it is really impervious to salt water. Galvanic potential between the stainless and the angle iron or tubing is almost zero. Internet pricing is super reasonable for the fasteners. After looking at all the options and looking at ours, I opted for the 3/8-16 316 stainless all the way through with nylocks.

Cutting an access slot all the way across the coach to access the back side and then through bolting would be the best option. A cover could be easily made that would allow future access.

There are quite a few fasteners across each of the bulkheads. Just one fastener could lift the entire coach. This is why with with many broken or weakened from rust/hydrogen embrittlement, coaches still hold together.

Unless you clean the backside of the big angle iron of all the rust, pressure will continue to increase from rust jacking. Rust jacking can cause any fastener to fail.

Roloks are not available from Foretravel as selling them for this application would expose Foretravel to liability for recommending this poorly suited fastener.

Pierce

Re: Rolok size

Reply #4 – June 12, 2015, 08:32:01 pm

Hi Brett,

Being an old unreconstructed structural steel draftsman for 10 years in a former life, my soul cries out for a cross-section drawing that shows both bulkheads.

Next, I doubt a 1/8 in by 1.5 in by 3-4 in long plate will do much good in spreading the compressive load on the box beam from the bolts. To paraphrase an old blues singer, "The will is strong but the won't is weak."

A single 1.5 in by 1.5 in 1/8 in thick ANGLE the length of the box beam will do a much better job of spreading the load. This is because the angle leg parallel to the ground is much stiffer than a 1/8 in thick plate. I would go for a 1/4 in thick angle myself. I'm guessing the box beam is 1.5 in tall.

Finally, it would be nice if the group put a spec together to describe what work needs to be done.

I'm staring at going to Sacramento to have my bulkheads inspected and possibly repaired and have yet to see one. Or a rolok.

best, paul

Quote

Let me post this for anyone going to Foretravel-- would appreciate your follow up:

Bulkhead Question

I have a question that came up in doing the inspection on the Crystal Ship yesterday.

Both bulkheads had been redone. Assume Wayne Musser did it, as it was Huck Bolted, not through bolted.

Also, the fiberglass 6" or so forward of the bulkhead and all the way across the bulkhead had been removed to give access, and a replacement panel properly screwed in place and waterproofed.
In the past, people believed that the Foretravel repair just used the Huck Bolts with no backing plate on the inboard side of the box beam. In other words, the force was concentrated on a very small area in the middle of only the inboard wall of a (likely) already structurally compromised box beam. NOT GOOD.
However, if, while he has access to the inner wall of the box beam he uses large "washers" to spread the load, it would be much better structurally. Best "washer" is 1 1/2" tall by 3-4" long 1/8" thick piece of steel with a hole drilled in the middle for the Huck bolt or through bolt. This would spread the compression load on the two vertical walls of the box beam where it should be.
If this is what they do, I want to be able to let everyone on the Forum know it, rather than let a misunderstanding continue to send bulkhead repair away from Foretravel.

If you have either seen the "inside" of one of their repairs, of could talk with Wayne or someone at Foretravel, I would appreciate it and it would absolutely be a positive thing for Foretravel.

Re: Rolok size

Reply #5 – June 12, 2015, 08:48:42 pm

Quote from: Paul Smith – June 12, 2015, 08:32:01 pm

Finally, it would be nice if the group put a spec together to describe what work needs to be done.

Contact Foretravel. They have already issued a white paper on the issue of bulkheads. It is not the responsibility of Foreforums to create a specification.

Re: Rolok size

Reply #6 – June 12, 2015, 08:50:10 pm

Does anyone have pictures of what we are dicussing.

Re: Rolok size

Reply #7 – June 12, 2015, 08:56:27 pm

So are you saying its forbidden for Foreforums MEMBERS to put a spec together?

best, paul

Re: Rolok size

Reply #8 – June 12, 2015, 09:19:02 pm

Quote from: John/Pat – June 12, 2015, 08:50:10 pm

Does anyone have pictures of what we are dicussing.

This is what a 1993 U300 with a very clean underbelly and no history of driving on salted roads has behind the bulkhead angle iron. Imagine just doing a quick repair without getting behind the angle iron and cleaning it. Sort of like sweeping the dirt under the carpet.

Since new owners arrive on the forum all the time, this is a topic that never gets addressed too many times. I tried to go back to the old posts but the archives don't seem to go back that far.

Pierce

Re: Rolok size

Reply #9 – June 12, 2015, 10:18:30 pm

How about this thought. If a thread rolling screw torques up, it's holding. If it doesn't, then something is giving.

I think in all (or almost all) of the pictures I looked at of bulkhead repairs, the inside face of the tubing is in very good shape, even if the outside is very rusty and "rust jacking". My bulkhead has no rust jacking, but even if it did, I think it is not unsafe to assume the box beam is in decent enough shape to use thread rolling or blind bolts. The worse that could happen is the bolts won't torque up.

There are not enough pictures around to do a statical analysis, but from what I see, the only real rusting occurs on the outside edge due to road salt, etc. Even wet bay leaks tend to flow along the floor and get in between the outside face of the tubing and the angle iron. Spread this apart, do a very good cleaning/rust treatment, and then apply a good rust preventing paint.

The design flaw is not the blind fasteners. It is lack of good corrosion prevention.

Re: Rolok size

Reply #10 – June 12, 2015, 10:20:17 pm

Quote from: Pierce & Gaylie Stewart – June 12, 2015, 09:19:02 pm

This is what a 1993 U300 with a very clean underbelly and no history of driving on salted roads has behind the bulkhead angle iron.

Pierce

Pierce, how long is that Rolok bolt in your picture?

Re: Rolok size

Reply #11 – June 13, 2015, 12:18:30 am

Krush,

Think it was 2 1/2" or 2 3/4". The sharp end goes a bit past the far threads. The new stainless as I remember are 3" but could be a quarter longer to be able to take the nylock. I bought a box of 50 for less than $30 from a east coast fastener company.

I never broke one off. They had all failed sometime in the past.

Pierce

Re: Rolok size

Reply #12 – June 13, 2015, 04:22:56 am

Quote from: John/Pat – June 12, 2015, 08:50:10 pm

Does anyone have pictures of what we are dicussing.

If I ever get a weekend when it does not rain I will get under the coach and take some pictures, I may even get around to fixing the bulk head lol. I have not drawn the box beam and angle iron together yet so a good look is possible.

I have removed a 6"+ path along the inside of the box beam the full width of the coach. I have double nutted and removed most of the Rolox (broken) bolts, the rest that will not come out I will sister bolt along side them.

This should give a good look at how this box beam is secured (or NOT secured) and how the bolts fail. It will also show the separated angle iron.
I will use a 3/8" zinc - grade 8 - 3 1/2" bolt with a 1/8" x 1 1/2" backing plate that will run all the way along the inside of the box beam. I will secure the bolt with a grade 8 - zinc - hardened nut, and grade 8 zinc washer, that will be up against the 1/8" backing plate. Between the 1/8" steel backing plate distributing the load the full width of the coach and the extra steel spreading the bolt/nut from the large washer this should give me almost a 1/4" of steel around the bolt/nut area.
WAY better than what the factory used.

Re: Rolok size

Reply #13 – June 13, 2015, 11:05:01 am

Quote from: wolfe10 – June 12, 2015, 01:58:17 pm

Cutting a hole in the fiberglass bottom and using a waterproof plug (if only a few), or remove a 6" piece of the fiberglass floor if all need reworking. is really pretty easy. The fiberglass is quite thin and a hole saw makes quick work of it.

This also allows you to use a proper backing. To me, a proper backing is 1/8" steel, 1 1/2" "tall" and 3" or so long. This spreads the load to the two horizontal parts of the box beam.

If you don't mind, please summarize again the size hole you recommend cutting, and the type (and source) waterproof plug you recommend. Thanks!

Re: Rolok size

Reply #14 – June 13, 2015, 11:18:28 am

David,

Here are the plugs I used: 1 3/8" Heyco plug PN 3837. But, any waterproof plug should work fine-- they will not be submerged (hopefully!), but will be exposed to road splash. If you can find 1 1/2" waterproof plugs, that would make the steel "washers" easier to get in.

Bulkhead Repair-- A Comprehensive Look

Re: Rolok size

Reply #15 – June 13, 2015, 10:27:20 pm

Quote from: Lon and Cheryl – June 13, 2015, 04:22:56 am

If I ever get a weekend when it does not rain I will get under the coach and take some pictures, I may even get around to fixing the bulk head lol. I have not drawn the box beam and angle iron together yet so a good look is possible.

I have removed a 6"+ path along the inside of the box beam the full width of the coach. I have double nutted and removed most of the Rolox (broken) bolts, the rest that will not come out I will sister bolt along side them.

This should give a good look at how this box beam is secured (or NOT secured) and how the bolts fail. It will also show the separated angle iron.
I will use a 3/8" zinc - grade 8 - 3 1/2" bolt with a 1/8" x 1 1/2" backing plate that will run all the way along the inside of the box beam. I will secure the bolt with a grade 8 - zinc - hardened nut, and grade 8 zinc washer, that will be up against the 1/8" backing plate. Between the 1/8" steel backing plate distributing the load the full width of the coach and the extra steel spreading the bolt/nut from the large washer this should give me almost a 1/4" of steel around the bolt/nut area.
WAY better than what the factory used.

Re: Rolok size

Reply #16 – June 13, 2015, 10:38:06 pm

You can see in the 4th picture that features the rolox bolt, how the bolt has rotted and failed from rust. The head is still attached and it will torgue up, but you can see how its rotted out in the middle. Only the bolt head that is threaded into the angle iron remains and appears to be a functional bolt, obviously it is NOT!
I will get this joint all cleaned up, painted, and the through bolts installed. I will be happy when this project is another that won't have to be visited again.

Re: Rolok size

Reply #17 – June 14, 2015, 10:04:13 am

Quote from: Lon and Cheryl – June 13, 2015, 10:38:06 pm

You can see in the 4th picture that features the rolox bolt, how the bolt has rotted and failed from rust. The head is still attached and it will torque up, but you can see how its rotted out in the middle. Only the bolt head that is threaded into the angle iron remains and appears to be a functional bolt, obviously it is NOT!

That is why I don't believe in the torque test! The head and first threads rust into place with the rest broken off in some cases. "Only the bolt head that is threaded into the angle iron" No threads in the angle iron, just rusted solid.

You have a pretty severe case in my opinion. You need to be able to see inside the tubing to see what condition it's in. After making sure your tubing is intact, I would sandblast everything visible and between the angle and tubing also using a Sawzall at an angle to reach up and get rid of the big chunks before blasting . You can rent the equipment if you don't have it. A HF PRESSURE sandblaster costs around $100 and does an outstanding job and a good size compressor can be rented. Will need a good filter mask to go with it. After that, I would treat the bare metal and then probably spray galvanize it (spray cans) and then use the most rust resistant paint I could find. Sandblasting gives great "tooth" to the metal for painting. I your case, I would make up some rectangular plates perhaps 5/16" thick to use under the nuts/washers on the far side. You no longer have the quarter inch total used by the Roloks so the 1/8" far side of the tubing will take all the force and yours don't look that good. Most any kind of corrosion protected fastener will finish the job. I would go 3/8" as no harder to drill that size. Grade 5 or stainless is all you need and with the number of them, it should be stronger than new.

After looking at the photos, to do a complete job, I would pull all the insulation and clean up everything. How is the other bulkhead?

A nice neat job documented with photos will be a selling point when the time comes and will help sell it. A partial repair can and will take thousands off the price and limit the potential buyers. You were lucky not to have had a failure.

Any of the pressure type (not syphon) work great: Search results for: 'sandblaster'

HD 4" or 4 1/2" grinder for cleanup before blasting: Search results for: 'grinder'

The medium TPI of the long metal blades will reach up between the angle iron and tin/tubing: Search results for: 'sawzall blades'

Pierce

Re: Rolok size

Reply #18 – June 14, 2015, 10:58:35 am

Brett what if one was to use a 1/8" u channel that goes from angle iron to the box that is degraded.

Re: Rolok size

Reply #19 – June 14, 2015, 11:31:40 am

That would certainly provide a stiffer clamping mechanism than a 1/8 in by 1.5 in plate. The downside of an exposed channel is the lower lip of the channel offers a convenient place to collect trash.

As everyone here knows by now this issue is very confusing to me.

The latest is reinforcing a tube with thru bolts, etc. My question is, "Are we bolting to something that has already been hollowed out and is it already a "whitened sepulchre?"

In other words, at the end of the day is there a strong path for loads?

best, paul

Re: Rolok size

Reply #20 – June 14, 2015, 12:57:48 pm

Paul I agree with you the more I read the more I feel Foretravel dropped the ball and should accept some responsibility for the issue. However, it looks like FT is taking the easy way out using buck bolts. In a degrading box beam it seems to me just postponing for the next owner

Re: Rolok size

Reply #21 – June 14, 2015, 01:12:56 pm

Yes, they are but much less expensive to have it done that way. They probably gave other options.

Foretravel did drop the ball on this and a few other things but check how many balls have been dropped by other SOBs. Foretravels are still a prize compared to others.

Pierce

Re: Rolok size

Reply #22 – June 14, 2015, 01:32:21 pm

IMHO the best way is with angle iron the full length ans coat all with cold zinc spray before bolting together. Then spray with a Rubberized undercoating before closing up bottom.
JohnH

Re: Rolok size

Reply #23 – June 14, 2015, 01:47:01 pm

Lon's box beam doesn't look to be in that bad of shape....looks mostly like surface corrosion on the front side and if it's been dry, not progressing. The outside (angle iron side) is what usually has the problems.

Re: Rolok size

Reply #24 – June 14, 2015, 02:55:51 pm

With rare exception, the Rolocks break 4-5 thread in-- where they enter the first/outboard wall of the box beam. Can they break other places? Once in a while. At one time I carried a collection of over 50 Rolocks all but a few broken at that point. Finally, after the bulkhead issue was "brought out of the closet", I ditched this ballast.

Also, remember, we live in the south and most of the coaches I inspect are NOT exposed to road salt. Suspect exposure to road salt brings a whole other level of problems. The serrated (locking) heads on the Rolocks leave the bolt standing slightly proud of the angle, forming a perfect entrance for water, or worse salt-ladened water. If you go back to my original writeup on bulkheads (now 6 years ago), you see that 1/2 can of automobile undercoating at the end of the job makes an excellent sealant for this water path. AND, THIS IS SOMETHING THAT ANYONE WITH A "PERFECT" BULKHEAD WOULD BE SMART TO DO. Water migration from the wet bay IS, repeat IS another common cause of rear bulkhead failure. When there is rot around the drop down sewer door, it is quite easy for the water to wick through the foam and soak the front of the rear bulkhead. Same for leaks on the passenger's side of the wet bay from leaks around the water pump/overflow.

As already mentioned, the angle beam should be overdrilled so the Rolock torques not on it, but ONLY on the two walls of the box beam. Yes, I have inspected two coaches where the angle had smaller holes and the Rolocks torqued on the angle-- a QC issue.

What I have never seen is a bad/separated bulkhead without finding at least handful of broken Rolocks when doing the "torque test". Yes, in Lon's 4th picture above, it is difficult to tell where the bolt is broken, or even if it is broken. Could even be the bolt is intact and the walls of the box beam denigrated. Not sure I would call that good news.

Lon did an excellent job of pictorially documenting the structure. And, without question I agree with his decision to remove that 6-8" section of the floor to properly repair the bulkhead.

And, from the pictures, you can tell that 2 minutes looking under your coach will tell you if you have a really bad bulkhead. It will NOT tell you if you have 4-5 broken Rolocks that need to be replaced, as the more that are broken, the more torque they put on the remaining bolts.

Totally agree, with Lon in opening the whole bottom, clean, chemically treat rust, coat with rust proofing (including drying out and coating the inside of the box beam) and use angle as a "washer"between the fore/aft members of the basement floor. Through bolt with 3/8" bolts. "You are now free to move around the country"

BUT, as Don has cautioned, using the right force on the right point to separate and then bring back together the bulkhead will be beyond most backyard mechanics. Don-- are you still hiring out as a consultant???

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