Plate thickness?

[Crazymanneil]

Hey,

As someone with limited experience working with steel I was wondering what thickness steel plate you guys would reccomend. I intend to use it to mount the gearbox and also (separately) to make brackets to suspend the bulk of my engine weight (60kg). From reading around it looks like standard harley transmission plate is around 5mm. I'm guessing 2x 10mm plates to take the engine weight as the mounts on the frame are 10mm.

Also need to make up a couple of additional braces from frame to back of engine. I've got 1.5mm wall 25mm steel tube.

All a bit of a guess for me. Sound about right? I guess I can try and if something breaks I can replace it with something heavier...

n

[coachgeo]

you might want to mention what plate your talking about. They might think your asking about the plate you should have put over the hole in your skull after they open you up to see what is making this guy crazy enough to build a diesel motorcycle.

From the conversation in your other thread will assume your speaking of a plate bolted to the block encircling the the flywheel, which acts as a bracket to hang things like the starter and tranny off of?

there is some harley pics in this site

http://www.richscyclecenter.com/engines ... index.html

Ultima with built in plate, might give you some idea
http://www.demonscycle.com/Shop/Control ... /SFV/31995

[Crazymanneil]

hey,

I'm going to use plate from the frame, under the gearbox (and mount gearbox on it) to the engine. I am currently guessing 5mm for that.

Then I am going to make 2 brackets to support the top of the engine which will take the majority of its weight. The lugs on the frame are 10mm thick so I was guessing something substantial there. Maybe 2x 5mm plate sandwiched together.

Then a couple of extra braces from the frame to the back of the engine at the middle which is what I got tube for but its only 1.5mm wall so not sure if thats enough or not.

Finally I'll also need to make a primary transmission plate like the one in the photo to keep the engine and gearbox the correct distance apart and also to carry a couple of bearings. Might make this out of alloy to keep the weight down though this would be the last plate I make up.

N

[johnfireball]

Hi crazy,
I used 6mm plate for the frame mounts on my dnepr daihatsu, they need to be rigid as they are quite long that is the distance between the frame and the mount holes is about 5". If yours are shorter you will get away with thinner mounts.
John.

[Sphere]

I've been taught to construct things with triangles and tube, L-bars of U-bars. I'm guessing that the weight of a 10mm plate will be significant. Remember that steel is roughly 8 tons per m**3.

[Crazymanneil]

Hmm I am considering 8mm plate at the moment but good point about triangles and shapes to add strength. Maybe I could use 6mm and some re-inforcing strips welded in. A good friend was round and we have worked out more or less how I'll mount the gearbox now. Will involve welding the support plate onto existing 10mm thick brackets so should be a good job.

n

[cumorglas]

Hmm I am considering 8mm plate at the moment but good point about triangles and shapes to add strength. Maybe I could use 6mm and some re-inforcing strips welded in. A good friend was round and we have worked out more or less how I'll mount the gearbox now. Will involve welding the support plate onto existing 10mm thick brackets so should be a good job.

n

8mm sounds about right if you slice up a couple of strips and weld them on perpendicular as ribs. you don't need to do a lot of this just where you have longer spans. I am i the midst of mocking this part on mine. being stateside i'll be using 1/4 and 1/8 plate. the front will be 3/4 alu. not so much because it needs to be, but because i have a bunch of it sitting around and it machines much nicer than the steel.

[cumorglas]

was just looking at the pics of the tiger with out engine. It appears to me that the engine is a stressed member. If that is correct I would not hesitate to get happy with ribs and what not to get that package as stiff as possible. a stock tiger handles pretty nice. in a large part due to how stiff the chassis is. where that engine is just about the worst place to have squishyness from a handling standpoint. it won't fall apart or anything it will just feel spongy going in to turns.

[Crazymanneil]

Superb comments cumorglas and I am inclined to agree. The frame is nice and chunky but as you say the original engine seems to be a stressed member. Its reassuring to hear your confidence that it should not break but you are probably right that it would affect handling. I'll go nuts with the welder I think and some nice thick plate. Also to make some re-inforcing arms that will go from the back of the engine to the middle of the frame.

Hopefully make some progress soon and have some pics to show!

N