Straightening 4mm Steel Plate (Anchor Roller Side Plates)

[nigelmercier]

Update on my anchor roller thread

I've removed the axles from the side plates using an 8mm drill, followed by a countersink bit. I think I'm good to go now, except for one problem. Some years ago the anchor roller got bent, and was hammered back into shape without removing the rollers. The sides are 4mm stainless, and one is bent by about 4mm over the long side, and a few wrinkles elsewhere...

I'd like to get it flat again. Any suggestions?

 

[sarabande]

the wrong way to do it is to put flat on hard surface, and give it an enormous wallop with a sledge hammer. It will bounce viciously and try to eat you...


I think I would use a gert big workshop vice, trap the side plate against one or more small 5 - 10 mm pieces of round bar in the right place, and gently squeeze hard on the vice handle, thereby reducing the curvature a bit at a time. I suspect you will improve the looks, but never make it pristinely flat again though.


Other more sophisticated methods are no doubt available from real engineers.

 

[coopec]

Nigel

Four mm is not thick so you should be able use a 3lb hammer (or a 10lb sledge hammer) on something solid like an anvil or maybe an RSJ beam. I'm quite sure you can't press it straight. (I would not hammer the stainless directly as you will mark it.)


This panel is only 1.5mm thick so it probably won't help much but they do mention using heat.

Whats the best way to straighten sheet steel | MIG Welding Forum ...
www.mig-welding.co.uk › ... › Metal Forming
Sep 12, 2012 - 18 posts - ‎9 authors
What is the best way to remove a crease, my knowledge of sheet metal work would fit on the back of a postage stamp. tigler, Sep 12, 2012.

Fundamentals of flame straightening. - BOC
https://www.boconline.co.uk/.../Fundamentals-of-Flame-Straightening41...
Table : Selection of torches for flame straightening. Workpiece thickness. Nozzle size for flame straightening. Gas consumption. Mild steel. Stainless steel.

 

[rogerthebodger]

Update on my anchor roller thread

I've removed the axles from the side plates using an 8mm drill, followed by a countersink bit. I think I'm good to go now, except for one problem. Some years ago the anchor roller got bent, and was hammered back into shape without removing the rollers. The sides are 4mm stainless, and one is bent by about 4mm over the long side, and a few wrinkles elsewhere...

I'd like to get it flat again. Any suggestions?

The only real way to straight the plate to nead flat is to use a hydralic car jack in a steel framr supporting the edges of the bend and placing the jack at the centre of the beng and gently operate the jack

Your local garage may have a press that will do the job they use then for pressing in wheel bearings.

The only thing you are doing to do with a hammer is to damage the "polished surface and then you will have to polish it again which will be a ball ache.

PS I made mine but it doesn't look as good as above.

 

[coopec]

My experience with stainless steel is that it is really hard to bend. According to google, a good workshop vise can exert a force of 1000lb. (half a ton)

Maybe if you used a bench press which could exert 5 ton you would have a better chance.

I know when I had my bow roller setup made people were turning me away and they had 100 ton presses. Eventually they used a 1000 tonne press (but I think they could have done it with a fair bit less) Try bending a 3/8 rod - it takes some force!

 

[ghostlymoron]

TBH the only way you're going to get them really straight is to get new cheeks made. I would imagine there's some metal fabrication skills in the Canaries but it may test your Spanish to find them although the marina guys should know.

 

[nigelmercier]

Thanks for the replies.

I've got it at home to work on it, so I could take it to a "man". I can actually bend it flat by standing on it, but of course it springs back. I'll try some packing pieces to raise the edges.

 

[sarabande]

My experience with stainless steel is that it is really hard to bend. According to google, a good workshop vise can exert a force of 1000lb. (half a ton)


That's the point of using small pieces of rod as leverage points to magnify the force at the points of contact. You can lift more in a wheelbarrow, than you can by bare hands.

 

[rogerthebodger]

Thanks for the replies.

I've got it at home to work on it, so I could take it to a "man". I can actually bend it flat by standing on it, but of course it springs back. I'll try some packing pieces to raise the edges.

Nigel you need to control the over bend quite precisely else you will keep overbending it then turn it over to bend it back. Each Time you do that the stainless steel will work harden making it more difficult to bend again.

You will never get it tully straight but you can get it better than it is now by little at a time using a precise method of bending. If you want it trully straight the only way is replacement.

Believe me been there and got the tee shirt.

 

[coopec]

the wrong way to do it is to put flat on hard surface, and give it an enormous wallop with a sledge hammer. It will bounce viciously and try to eat you...
.

Sarabande

On reflection that is probably very good advice.

I tend to forget that even as a 5/6 year old I was using an axe/sledge hammer to help Dad cut firewood for the wood stove and as a result my aim is quite accurate. (I suppose most people have never wielded an axe or sledge-hammer.)

 

[nigelmercier]

Thanks for the replies, I've got them reasonably flat now. The kinks I removed by holding in a vice and bending with a pair of big Stillsons. The general warp by packing the edges on my workbench and using a G-cramp to pull to the bench. Over-bending could be adjusted until it was correct on release.