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Topic: Safety blocks (Read 6949 times) previous topic - next topic

Safety blocks

Hi every one, i did search for the information about safety block to place in frame when dumping the airbags to be able to get under the Rv
A- are they available to buy?
B- what size they are supposed to be?
C- can i just cut some 4x4 pieces to use?

Edmond
1998 u295

Re: Safety blocks

Reply #1 –
I went to harbor freight and bought eight of the 2x2x12 hitch extensions. They work perfectly (except on my IFS front) but that's another story. They store neatly next to the basement drawer too.

Re: Safety blocks

Reply #2 –
I use 12" 4x4 PT blocks
Have used them for 10 years now.

Re: Safety blocks

Reply #4 –
What is the process for adding these blocks? Can one person do it?

Re: Safety blocks

Reply #6 –
One Hint: Make sure your air pressure is at the maximum =  120# so that the rear of the coach lifts all the way up. The rear is the heaviest, and it takes more air pressure to lift it. 

Re: Safety blocks

Reply #7 –
Quote from: James Bock –
I went to harbor freight and bought eight of the 2x2x12 hitch extensions. They work perfectly (except on my IFS front) but that's another story. They store neatly next to the basement drawer too.
I second this approach, thick sidewalls, affordable, tough. Don't drop them on your toes.

Re: Safety blocks

Reply #9 –
4x4 lumber does work just fine also.

Re: Safety blocks

Reply #11 –
Quote from: rvquestion –
Sorry , what PT stands for?
Because i think carrying 8 twelve inch 2x2 tubing with 1/4" wall is to much of weight
I believe PT probably refers to "pressure treated" ground contact lumber.

I will respectfully disagree with Justin and Dave.  It is possible (however improbable) for a wood block like shown in the photo to split down the grain.  If one was to fail, the others might also give way in a cascading event.

In my opinion (everybody has one), it is safer to use steel safety stands as recommended earlier in this thread.

The weight of 8 steel stands will be insignificant compared to all the other junk you will accumulate in your storage bays.

HOWEVER, it is your coach and your life, so you should do whatever seems safest and most appropriate to you.  DWMYH

Re: Safety blocks

Reply #12 –
When I bought my coach it came with wooden blocks and I made my own as I wanted them longer.
As a retired Heavy Duty Mechanic I had be blocking heavy equipment with wooden blocks for years
without any problems. the blocks I am using are 3 x 31/2 and are hardwood.

Re: Safety blocks

Reply #13 –
Chuck's correct, the weight of 8 stands isn't going to matter too much. 

As far as safety, solid steel would be better than tubing.  Of course the safest thing would be to never get under there. A person can paralyze themselves with "what if" scenarios.

Re: Safety blocks

Reply #14 –
I've had a question about aluminum square tubing for safety blocks from another forum member. I suggested he find out the strength of the aluminum before using, I prefer to use steel 1/4" wall personally. Jim. 

Re: Safety blocks

Reply #15 –
The compressive strength of 3/32 round tubing is the weight of the coach individually, but they must be placed perfectly square. The 1/4" square tube gives you endless safety factor even if you put the in out of square. 1/4 in aluminum alloyed would be fine. I use 1/8" galvanized pipe with no concerns. BUT I was taught never to use wood on end with the grain.  Figure 4000+ lbs per square inch 4x4 =  12.25 sqin. 14000 lbs each Any internal flaw would go undetected till it failed. Lots of stories about Model T spokes made from oak failing being to brittle. 🤷most metal has some engineering and will support a lot of weight end to end in compression.

Key takeaways
A 2" x 2" x 0.250" ASTM A500 Grade B steel tube has a minimum yield strength of 46,000 psi.
For a 1-foot length, this tube is more likely to fail by crushing (yielding) than buckling.

 DWMYH

Re: Safety blocks

Reply #16 –
Can someone speak to how flat the coach should be in order to use blocks? I feel like if I am on uneven ground there would be risk of twisting rhe body. Is this an issue or am I over thinking it.

Re: Safety blocks

Reply #17 –
I would think if you can put them all in its level enough

Re: Safety blocks

Reply #18 –
Well, the steel tubing is undoubtably stronger than wood, but  to me it seems more likely that a piece of steel square tubing is more likely to "kick out" under pressure if improperly placed on the steel frame. Probably unlikely but possible.  I would want a plate ( or channel iron) welded to the ends to prevent this from happening. 

According to the chart above (Dsd post) pressure treated yellow pine at almost 8,500 lbs before crushing, I feel it's a very safe option. I always use all eight blocks ( 8 x 8500 =  68,000) and we weigh about 28000 fully loaded.

I may switch to steel one day but I would want something welded to the ends so there is no way they could slip.

Re: Safety blocks

Reply #19 –
Quote from: FourTravelers –
Well, the steel tubing is undoubtably stronger than wood, but  to me it seems more likely that a piece of steel square tubing is more likely to "kick out" under pressure if improperly placed on the steel frame. Probably unlikely but possible.  I would want a plate ( or channel iron) welded to the ends to prevent this from happening. 

According to the chart above (Dsd post) pressure treated yellow pine at almost 8,500 lbs before crushing, I feel it's a very safe option. I always use all eight blocks ( 8 x 8500 =  68,000) and we weigh about 28000 fully loaded.

I may switch to steel one day but I would want something welded to the ends so there is no way they could slip.
So everything is level. The ends are cut square. They always stay in position when lifting coach to remove. I agree with you but cant imagine one kicking out. I've never had one fall out unloaded even in high winds. I've even heard of one of our members forgetting to remove one and driving down the road without issue. You would only need a button for the tube to go over??? Scott