Tube to plate; Best way?

[Photog_Dave]

I'm needing to weld 1in mild steel tube to 1/8in plate. There will be a plate at either end of the tube. It is a basic engine support on a motorcycle project.

The two ways I can see me doing this are
1/ cutting the tube 90 deg and welding it flat to the plate (see fig 2)
or
2/ drilling a hole through the plate slotting it in and welding it at both sides. (see fig 1)

I've done a quick sketch showing what i mean if you can understand it.

I'm wondering if any of you Pro's out there would recomend any of these or is there a third better option.

 

[oz.]

I'd go for drilling a hole and welding both sides. You could put some small triangle bracing on as well

 

[craigthewelder]

I'd just weld it straight to the plate, that should be plenty strong enough.

 

[pedrobedro]

Straight to the plate here as well, that's how I made the mounts that held my car engine and they never budged. It was a lot heavier than a bike engine as well. I used 40x3mm RHS to a 3mm plate, oddly I can't see your pictures.

 

[Bsmith]

Straight to the plate. 1/8" plate will bend before decent welds will give here.

 

[hotrodder]

Only a small portion of the drawing loaded so i don't know if a breather hole was included for method 1. I'd go straight to the plate as well but drill a small hole in one of the plates (centred on the tube) to allow for expansion of the air inside as it's heated

 

[Photog_Dave]

Hopfully this one loads up better.

Thanks for all the quick responces. Especially like the tip on drilling the hole Hotrodder It's the little tips like that that I need to learn. Once I get going with it I'll put some pictures up (mmmm maybe do a project thread)

4/1 in favour of straight to plate so far. I think from what you guys are saying either would be strong enough.

One extra little question/variable to throw in, is the engine is a big single and the vibrations are going to be quite strong, do you think that is going to cause any problems?

 

[dopplershift]

Are you going to use any rubber/synthetic bushes, or bolt straight the to steel mounts you're making? I would have thought bushes would be preferred?

 

[Photog_Dave]

Are you going to use any rubber/synthetic bushes, or bolt straight the to steel mounts you're making? I would have thought bushes would be preferred?

I've been trying to source these on line but not getting any joy withe sizes. If anyone has anysuggestion of a good suppier it would be appreciated. The engine is a Husaberg 650 single so the vibrations are going to be a factor.

 

[hotrodder]

...One extra little question/variable to throw in, is the engine is a big single and the vibrations are going to be quite strong, do you think that is going to cause any problems?

Will make things more prone to fatigue failure, cracks growing from any weld defects/sharp edges etc will be more likely.

You could add a vibration damping mount quite easily, there are universal mount kits available (that'll be an expensive source, just the first link with useful pics from google). If you have the kit available to make most of the bits needed then you caould just buy the bush part and make the mount to suit it

 

[pedrobedro]

Are the mounts going to be horizontal and bolted at both ends ? They would be better angled down and supported from underneath and you could use Land rover engine or Fiesta gearbox mounts to support them and suppress some vibration. Both are cheap and easily applied.

 

[Photog_Dave]

I like all these suggestions. It's very easy to come up with a plan and get fixed on it then not see if there is a better way.
Below is what I'm looking at.
There are two drop down parts on either side of the engine though the scribble only shows the one.
I have through your suggestion been looking for appropriate sized bush to use though finding one that will be a good size is difficult (I'm limited on the diameter of the short horizontal bars due to engine casing. I may be on to something with these guys

 

[pedrobedro]

You can use bushes without the outer metal sleeve or buy polyurethane bushes from kit car manufacturers. These are used in a lot of other applications, you can find outer tubes to fit them and weld what you want before you fit the bush in the tube. Those ones are 90p each + p&p in the Triumph Herald section.