Thread: Question on reinforcing 1/4" steel

I'm fabricating a bracket for a mower deck so I can use on another tractor. What I need is a basically a flat bar of steel to mount over a pulley.

The bracket will span 14" and I'm trying to use 1 1/2" wide x 1/4" A23 hot rolled steel. The bracket will be mounted 5" above the deck by two 3/8" thick x 1 1/2" wide pieces of the same steel.

The deck weighs about 130 lbs and the two lifting points will be about 4" from each end.

Belt clearance is an issue so I'm trying to use the 1/4" steel over the 3/8".

My question is, could I use a small piece of steel near the center of the brace to keep it from flexing?

Granted, I positioned the 1/4" steel across two pieces of wood 12" apart to test for flex and with 200 pounds on top, it barely moved 1/16". The 12" gap I used was factoring in a 45 deg support under each edge of the bracket.

I don't think I would have any issues, but just looking for some advice on making this 1/4" thick piece of steel more rigid.

If I have to use the 3/8 I can make it work but the 1/4" stock gives the belts more room to flop around a little.

Here's a pic of the test bracket made out of wood. This cross piece is 7/16" but I won't be using one that thick.

This is with the deck in the down position, when raised it's very tight to the drive belt.

Should give you an idea of what I'm woorking with.

Welcome to the forum.
Pedantic I know, but a small piece of steel in the middle of your brace will not stop it flexing - it just won't flex as much.
In something like a mower where I would expect a bit of jolting and bashing to happen I would say the deeper* you can make that brace the better; whether that is with 3/8" material or 1/4" with reinforcing depends on what you can fit in. I don't know where the critical points are for your clearance issues are, but I would even be tempted to consider a brace made out of say square hollow section (we can get stuff down to 5/8" square here although it is hard to find), stepping it in places and perhaps with 1/4" or 3/8" material at really tight spots.
The other suggestion I would make is perhaps make the cross piece so that it bolts on (use nyloc nuts). At least that way if it does tend to bend with use you can take it off and straighten it easily.

*to maximise rigidity the depth of the section is key. A solid piece will be slightly more rigid than a hollow piece of the same size but will weigh a lot more.

Michael

Thanks for the tips.

I would like to make the top piece removable instead of the entire bracket. I did however design it to be unbolted from the deck, but having a removable top portion would be nicer.

I see what you're saying about going deeper...I could possibly go to 1 3/4" but that's going to be a stretch....no pun intended.

Here's a sketch of the bracket.

The red boxes are at the base and would be a reinforcement 90 deg to the vertical pieces.

The 45 deg lines would be reinforcements to the top piece.

The two black lines on top depict the mounting tabs for the lift hangers and will have a 5/16" hole drilled in them.

I think that the bracket may want to bend (bow inwards) at the section between the two corner braces. The outside corner braces would stop bending there. How about two gussets made from the same 1/4" plate welded between the sections, outside the lifting points and meeting with the point where the corner braces are?