Topic: Machinists with aluminum experience

[greenjeans]

I can get 5052 H32  aluminum and have it cut on a waterjet with any file that I provide at a pretty reasonalble cost.

Been reading a little on the different grades of aluminum and have a couple questions -

Would a shape cut with a waterjet be accurate enough for something like a triple ?    The file is accurate - just wondering if you would have to consider the width of the stream of water or would the machinery handle that ?  I would imagine that you could tell the jet to cut on either side of the lines in the file - Or would it have to be machined differently ?  Milled etc.

I can also have the same company annodize the part.   Supposedly hardening the part further.   Any thoughts there ?

[HondaMan]

The shape should be close, but I think final centering and dimensional finishing would still be needed. When we do waterjet parts for the machines, they are referred to as "rough cut" surfaces (we build automation machinery where I work). If we have to precisely locate anything in these parts, they are milled (or CNC'd) to position and tolerance, like normal parts.

Anodize: it makes the surface a little harder and more scratch-resistant (or makes pretty colors!), but otherwise doesn't add a lot of strength.

Hey: I heard Frank came by your place on his epic American ride?

[Markcb750]

You certainly could cut out the outside shape with the water jet, the taper that would be in the outside of the part would be similar to the casting draft in the original components.

You would need to make the the fork & stem features by drilling & boring.  creating the clamp and its threaded features would need a drill, c-bore & tap.  A saw cut to split the clamp. 

I would increase the wall thickness around the fork clamps significantly, because the aluminum will deform more from the clamping motion and will need thickness to approach the original part's strength.

Aluminum does not harden during the anodizing process, the surface does get hard, harder than heat treated steel, but this is only microns deep, not significant to the strength of the finished part.  I do not know the exact specifications of the alloy you have but most aluminum will harden with aging due the allowing element  copper which precipitates from the crystal structure causing the aluminum to harden and gain strength.

Look over Joker components, you will note their part's size & design features to create a good triple tree component. 

Good luck, sounds like fun!

[calj737]

Everything they said, but if you do want to make your own triple, I'd step up to 6061. It's a neglible cost difference but the strength is better. The Joker products (I have their tree actually) is from 7000 series according to their website. I had to press the stem back to suit the 550 from the 750 design, and it took a 55 ton press to do. Talk about tolerances...

Their stuff is pretty dang elegant and very well made to Mark's point.

[754]

Stay away from 5052.  Better formality, and welding than some alloys,  but lwer strength Can't you bring your own piece.
 Around here the water cuts seem very perpendicular, it's plasma that usual angles a bit.

Are you trying to cut the fork holes in the triple accurately?  Not the best idea, but could work. Cutting the other features no problem.

[Garage_guy_chris]

Your gonna have additional machining to do after the water jet no matter what you do.  you still need the holes and threads for the fork pinch bolts and the stem pinch bolt. i would also suspect you will need to machine pockets for the stem. 

If it was me doing it with a minimum of tools and or knowledge
1. have the outer profile and holes (done undersize) cut on a water jet,   
2. mount on vertical mill and bore holes to proper diameter with boring head
3. do finishing work on mill pinch bolts and pockets with an end mill
4. Finish the outer profile with a belt sander or spindle sander. 

[greenjeans]

oh well - I probably won't be doing this afterall.   I make signs and a company that I use for lettering can do the watejet cutting - they only use the 5052 and aren't keen on me supplying my own material.     I was just thinking that if this might work, I'd give it a shot.

Hondaman - yes, frank stopped by for the night on his ride.   Was he able to stop by your place in CO ?

[bjbuchanan]

They probably only do 5052 because they have a little machine. I was on an air national guard base once, touring the facilities and they do in house water jet.  Their machine is a monster as far as waterjets go, they make any repair pieces in house for their planes

You can get finer work through more time in the machine. You would still do a final boring and everything but good machines blow your mind with what that funny looking water can do

[Vicman]

We do quite a bit of "job shop" waterjet work. As mentioned above, I would not recommend 5052. 7075 would be my first choice for two reasons, first strength, second it polishes up much better than 6061 which would be my second choice mainly for cost.
We approach our waterjet parts the same as Hondaman. Rough out the shape and put it in a mill.