[Li'l Dave]

Do any of you Boulder/Denver monkeys know how to use Autocad pretty well? My father is making me a deal around me being able to replicate an outer MRP plate on Autocad. I have autocad on my computer, so I'm not asking for a free copy or anything, just some help in the design phase. Thanks, and let me know if you can be of any assistance in this matter.

Dave

 

[ChrisKring]

I don't live in denver but I can give you some quick pointers that would apply to designing in on any 3d cad system (autocad included). Btw: autocad does not suck that bad for mechanical desing. Sure, the surfacing package is not great. However, what do you need it for anyway to design bike parts.

Start off with a 2d profile of the ring.

1)I would start with a center point and put the bolt circle pattern in.
2) Then place the bolt circles in.
3) measure the outer diameter and make that circle
4) measure the inner diameter that contacts the crank flange and make that.
5) measure the inside diameter where it flares out.
6) fudge some curves in between these two inside diameters to make the "fingers" that attach the ring to the crank.
7) trim up the inside diameter and make it a polyline.

Now in 3d
1) Extrude the outer Dia. the thickness of the ring.
2) Extrude the bolt holes an inch long. Subtract them from the previous solid.
3) Extrude the inner Dia. an inch long and subtract it.

At the countersinks in the bolt holes.

In solid modeling (as opposed to wireframe or surfacing), you design a part just like you would build it.

good luck

 

[Li'l Dave]

thanks for the info, that sounds like a good way to get me started at least. then I'm just going to have to touch it up a bit. by the way, do you know if I can take an autocad drawing into solidworks? I have some mechanical engineer buddies that can help me render it that way. Well, I'll let you know what I can come up with, I'm having fun with this.