Straightening a Logrite

kelLOGg · August 30, 2021, 09:56:35 AM

A customer forgot his 5' logrite when he delivered logs - it has a bend in it and I thought I would offer to straighten it for him. I have a 20T hyd cyl that extends about 20" more. I plan to use it and a heavy chain and give it a shot. I have straightened steel ramps this way but never an aluminum alloy. The bend is not in the plane of the hook so it looks like it got run over by a big truck. Since it is someone else's property I don't want to screw it up. Any advice? I will check with him if FFers think it is safe to try.

GAB · August 30, 2021, 10:07:32 AM

If I was considering that task I'd use a hydraulic press and some Vee blocks.
GAB

Tacotodd · August 30, 2021, 10:16:07 AM

Get hold of LogRite and see what they can tell you as far as strength retainment goes. I'd also take the hook off to keep it from spinning in the press if you aren't right next to it.

charles mann · August 30, 2021, 11:30:41 AM

As GAB said, V blocks or better yet, a pipe mandrel designed for bending pipe

mike_belben · August 30, 2021, 11:55:34 AM

vee blocks in the press. roll it in the blocks and mark the high spots so you know exactly where to press.

KirkD · August 30, 2021, 11:58:16 AM

We use to use a wide hardwood v-block on bent motorcycle forks. They have less of a chance of creasing than metal.

Tam-i-am · August 30, 2021, 12:04:12 PM

It is not that big a bend so Vee blocks and a press should get it to relax nicely.

Southside · August 30, 2021, 02:06:41 PM

How you gonna feel when he tells you that bend was custom done to allow for finger room when loading his trailer and his late father-in-law toiled for days to get it just right? ;D

Old Greenhorn · August 30, 2021, 03:13:24 PM

I have done these type things before, it can be more tricky than one might first guess. Because it is not yours and you are trying to do something nice and not make it worse, you have to be careful. V-blocks will work but they will leave gouges in the shaft where there is a line of contact and you reach the force necessary to effect a reverse bend. What you really need is surface contact around the radius to spread the load out. So if I were doing this, here is now I would go:

make 3 blocks from hardwood with grooves in them to match the outside radius of the shaft, two of these should be longish, 8-10" to again spread the load out, the 3rd should be around 4-6" long, this is your pusher block. On the 3rd one try to have the groove perpendicular to the grain to minimize splitting potential.
Find the high spot and center of the bend and mark it. Place the high spot straight up and right under the arbor. Space the two evenly away from the center, start with them as far apart as possible. Begin your pressing and watch carefully to see where the shaft is reacting. Adjust your blocks as needed to prevent adding new 'alternate' bends. Heating the bottom side would help, but the paint will be gone. Take you time. When you get close, you will likely have to overbend it so be careful. You can measure the distance from the bottom of the shaft to the deck to know how far you went, then release, check it, and if it needs more, go a little deeper on the next push. If you don't measure you won't know where you were.

Take your time, take your time, take your time.

Tom King · August 30, 2021, 03:24:49 PM

I would rather pull it back out, than push it. Secure, and padded on the hook end, and a long padded pipe over the handle.

I'd like to know what type of aluminum it is first though. Some would crack, and be better to leave it alone.

kelLOGg · August 30, 2021, 04:14:09 PM

Now I know it is certainly a job for someone else - like a machine shop. Here's what I did (after talking to the owner who said "by all means") and then gave up on.

I could over-bend it easily but it wouldn't stay bent. I wasn't going to apply more force for fear of introducing another bend near the ends and of the lack of stability of my setup. Glad I stopped before doing a favor turned into a mistake.

Silverfoxfintry · August 30, 2021, 04:36:10 PM

Most aluminium alloys "age harden" this means that you can soften the alloy by heating above the critical point. The alloy will soften. Straightening the now soft alloy is now much easier.
The original strength will return to the metal in a couple of days.
Aluminium alloy rivets are annealed before use. If not kept in a freezer they harden again in about 24 to 36 hours.
Interesting, when cigar tubes are formed, the process happens to fast for the alloy to work harden.
(Or so I remember from college lectures 50 odd years ago)
Hope this helps.

Silverfox.

Old Greenhorn · August 30, 2021, 04:41:56 PM

Silverfoxfintry, this is a steel hook if I recall correctly.

Actually that setup you have is a pretty good idea and as long as the shaft does not snap around on you it should work. BUT I have no idea what Kevin has used when he designed that hook. Since it is their 'Xtreme" hook I am going to guess he picked a higher end high tensile steel. From what I have seen of Kevin's design skills and habits I have come to respect his abilities as someone who has a good handle (pardon the pun) on it and knows exactly what he is doing and more importantly why. (In short, the guy has "game".)
SO I am thinking if there is a chance to fix that, heat will be needed. There is no way knowing what the after effects will be once heat is applied because you are basically annealing the material and letting the grain structure re-organize a little bit. You would need to know the exact alloy being used and what production processes it has already been through. Anything else is guessing, at best. But even a blind squirrel finds a nut once in a while. :D It could work, maybe.
You gave it a good shot and were probably very smart to stop when you did. Maybe give LogRite a call and see what Kevin thinks. One thing is for sure, those hooks are tough!
@Tam-i-am any thoughts?

GAB · August 30, 2021, 07:24:44 PM

Quote from: kelLOGg on August 30, 2021, 04:14:09 PM
Now I know it is certainly a job for someone else - like a machine shop. Here's what I did (after talking to the owner who said "by all means") and then gave up on.

I could over-bend it easily but it wouldn't stay bent. I wasn't going to apply more force for fear of introducing another bend near the ends and of the lack of stability of my setup. Glad I stopped before doing a favor turned into a mistake.

Looking at the setup in reply #10 I find the most appropriate item in the picture to be the street sign.
GAB