Jump to content

Recommended Posts

  • 1 month later...

I got my recovery lugs welded up, bit ahead of myself there lol, but they came with the laser cuttings for the new rear crossmember and the radius arm infills.

im also working on another gearbox crossmember, I wasn’t 100% happy with the other one, but will see how this one turns out 🤷🏻‍♂️
 

recovery eye is 20mm plate, mounting plate is 10mm. 2 passes at 180 amps.

 

 

F92D4E62-2743-452C-98F8-43B470DEAB95.jpeg

8F30423A-27F6-4278-B497-63CC3C852E1D.jpeg

04D00E98-C0BA-4684-96E9-31511CBAFE52.jpeg

  • Like 3
Link to comment
Share on other sites

They look beautiful and I'm sure they are more than strong enough, just welded recovery points make me uncomfortable. Please don't get me wrong I would use yours. When I made a recovery point for the ibex I used 10mm angle with webs and additional thickness welded on so the bolts went through the same bit of metal the load did.

Mike

  • Like 1
Link to comment
Share on other sites

@Blanco Im guessing those would be 'stick' welded. While 'stick' doesnt get the hype or glamor of 'Tig' there is nothing wrong with it in the right hands. The range of rods available and its ability to be welded in all conditions make it still the go to in many critical applications. I have only done it a few times, but have a great appreciation of it.

 

@miketomcat @landroversforever I understand the hesitation regarding welded recovery lugs. The way I see it there are many critical components on our LRs that are welded and see high cyclic loads (fatigue) and we dont give them a second thought. While there is some "controlled enviroment" they certainly are not 'NASA' spec. For a welded joint such as my recovery lugs, the general rule of thumb is that since the it can have a full fillet weld right around the lug to mounting plate, the fillet weld size (leg length) should be a minimum of 0.75 the thinner of the two materials. In other words, the weld will equal/exceed the strength of the mounting plate.  

Another view point (may or may not be moot) if we look at the volume of the 3.2tonne bow shackle pin that is in sheer, it has a 19mm dia pin, 20mm in the lug. Thats 5670mm3. The fillet weld (that is in tension) at 7.5mm leg length has a volume of 9281mm3

These recovery lugs are to always be used with a bridle (both lugs used at any recovery)

So no, no notch etc, only the fillet weld you see.

Edited by uninformed
  • Like 2
Link to comment
Share on other sites

Beautiful work but the design ro me looks better suited to a tail gate hinge than a recovery point?

Doesn't  the offset hole put the stress in a peeling down direction?

As I am NOT an engineer I have no idea what it's physical abilities actually are though.

Link to comment
Share on other sites

6 minutes ago, missingsid said:

Doesn't  the offset hole put the stress in a peeling down direction?

As I am NOT an engineer I have no idea what it's physical abilities actually are though.

I don't know where these will be mounted or used, but the"peeling" action you mention would depend on how they are mounted. Will these be mounted as shown, so mounted on top of something, as if they are that looks like a good design. I can understand the "peeling" action if mounted vertically with the hole at the top or bottom.

Lovely looking welds - so neat I thought they looked Tig welded!

Link to comment
Share on other sites

@missingsid @Dr Strangeglove they have the mounting plate in the vertical plane, recovery lug in the horizontal plane, shackle hole is vertical.

The hole is offset so the resultant force line continues through to the centroid of the chassis rail/crossmember attachment.

The welds are mostly in tension, the only bending moment would be any vertical change in height of the recovery line ( but generally very little) 

The welds are TIG, as with all my work on this build. 

  • Like 1
Link to comment
Share on other sites

On 7/18/2021 at 2:02 AM, uninformed said:

 

Another view point (may or may not be moot) if we look at the volume of the 3.2tonne bow shackle pin that is in sheer, it has a 19mm dia pin, 20mm in the lug. Thats 5670mm3. The fillet weld (that is in tension) at 7.5mm leg length has a volume of 9281mm3

T

Just to correct this point - the volume of the shackle pin in the plate is not what you are interested in and offers absolutely no insight into the strength of the connection. From a pin perspective, you are interested in the two shear planes where the pin exits the face of the plate.

The shear area (assuming no threads in the shear planes) is 19^2 PI/4 x 2 = 567mm2. You would then go on to calculate the shear capacity of the pin based on its yield strength, the bearing capacity of the plate, the capacity of the weld group and also potentially the tensile capacity of the weakest section of the plate. this will identify the weakest link. I wont bore you here with those numbers.

Another comment is that the configuration of the weld group will also be a factor in the strength of the connection - you cannot just compare sizes (ooo-err missus) and assume all will be well. Also, depending on the direction of the load, the weld will be in a combination of shear and tension / compression, not just tension.

Welded recovery points are absolutely fine if, and only if, they are appropriately designed and competently fabricated. (this is not a pop at the OP, just a statement of fact).

Lots of love,

Bish 

CEng MICE.

  • Like 2
  • Thanks 1
Link to comment
Share on other sites

@bishbosh feel free to bore me 👍

 

20mm plate was chosen as it’s the max thickness that comfortably fits the 3.2Tonne shackles I use.

10mm mounting plate was gut, 4x1/2” bolts because that’s good enough for a pintle should be fine for two combined recovery points. 
 

0.75 weld size rule was given to me by a engineer. 
 

Hopefully with good practice the welds will be mostly in tension. I don’t compete so set up time is not a real issue. 

Link to comment
Share on other sites

  • 1 month later...
34 minutes ago, Stellaghost said:

Curious, did you scrap the previous ones, asking because the welding around the bush section does not look as uniform as the previous ones you posted, nice work though regards Stephen

No.

that’s a added 4mm infill plate (both sides) over the top of the main webs. Looks worse than it is because I gave a quick sand and it highlights the highs/lows due to the heat discolouration left in the lows. But it is also not as pretty as the main web passes. Pre heat and no peddle makes it a little more tricky.

 

They will do the job though. 

Link to comment
Share on other sites

Got the Nissan bushes pressed in (really need to build mine) and bolted the arms and housing up. Castor and pinion are on point. 3 degrees at ride height and pinion is spot on for the double Cardin shaft.

still lots of clearance checking to do and double check.

 

 

9A1E4A66-7E39-4255-BEF9-FE81DFEF5752.jpeg

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy