Top Cap Machinist?
 

Does anybody have a program to custom mill a new top cap for the Bravo drive? I know that Billet Marine is cutting some water cooled aluminum ones, but I'm looking for mine to be carved out of a chunk of stainless. I believe that there is a steel race that would need to be pressed in along with a bearing.

Will do. Please post your address for me. The board doesn't allow you to attach photos to e-mails.

There are two steel surfaces on the top cap. One is a flat ring, the other is pressed onto the aluminum tower. Both have bearings that rub on them.

There is also a center bearing that is pressed into the tower.

I see 3 surfaces that are critical. Proably half a dozen others that are important. I don't know how that flat wear surface is held in. Is this too complicated to reverse engineer?

My hats off to you machinists; I have to buy mine assembled and painted, don't know a bearing from a race. I have taken apart way too many things in my life that when re-assembled work but you have a few "extra parts' left.

I have to go to work and pay you guys!

I’ve been machining water cooled Billet Bravo caps since 1995 with great success. Be careful if you have some one reverse engineer them. Not all caps are the same from Mercury. We have found some that are way out of spec.
It’s funny how more people don’t use them. They are really an advantage on the left hand drive because all the force in pushed up. We also use full length studs to save the “case” if there is problem.
Next week I am running a new batch of caps. I’ll look into the costs of doing some in stainless since the machines will already be set up. PM me with your phone # and I’ll get back to you. Our aluminum caps are $ 299.95 with the drive shower and all the bearings installed. Check out the web site at: www.getrealperformance.com or call me at: 805-968-5672

Generally stainless cost’s over aluminum is about 40% more. I’m going to make a run of 15 pcs., that’s one full bar of material. I’ll keep everyone posted as soon as their done. I’m always open to new ideas for new products.

Guys, you need to remember that stainless is a piss-poor conductor of heat. The aluminum cap will pull significantly more heat out of the drive than a stainless cap will.

If rigidity is what you're after, there are several aluminum alloys that are pretty stiff. Good ole 6061-T6 is dang hard to beat when you are looking at the whole picture. Billet 6061 is tons stronger than the cast stock caps, and in my opinion, is strong enough (not the stockers, but the billet ones). Plus you retain the heat properties of aluminum.

I just don't see real benefit from using stainless.

My .02

They can case harden aluminum also.Can be chromed if he is looking for it to sparkle.

DAMN! mcollinstn all ways a ball buster! :D :D

Rag's

GRP-you have mail.

Mark, I'll contact you based off our conversations.

Hey, Rags, I wore my "Size Matters" Tee Shirt last night. It has a bottle of something I've never heard of on it.

We went to watch some jazz band at a local bar, and they didn't have any of it there.
What is that stuff?

I was thinking the same thing, stainless may cause excess heat buildup in the drive and add more weight to the boat:) If you did need something reverse engineered I could do it but in this case you'll probably be better off just buying it from getreal. A few years ago we reverse engineered a snowmobile crank case for a guy that does grass drags all year long. He wanted to use a standard crank and jugs but we added a forth cylinder and changed the intakes to give it more air then we machined it from billet.

What I was thinking was that if a new top cap was cut, then it could serve as a wing plate for the steering rams.

"Best" place for steering rams to connect is on the same centerline as the driveshaft. Above or below that gets into geometry changes as you trim up and down, but it's not a big deal and people mount them all over the place anyhow.

BMax does the steering boss thing right. Find a picture of one of them.

That is one of the things that is really complicating this steering install-the fact that I'm insisting on the correct geometry. It's really easy to screw this up. I've seen the wing plates bent up like a pretzel from messed up geometry. I'm not gonna go there.

I heard Billet Marine was looking at making a SS cap. Their aluminum water cooled cap is a nice piece.

Cord,

Max Machine Worx makes a nice cap, but not cheap @ $400. I'm replacing my Billet Marine caps with them soon. Let me know if you're interested in the Billet Marine caps. They would need new bearings/races.

Chris

As mcollinstn said...........
 

Stainless suck's for disapating heat.

For the about the same money your better off
using Titanium.

I don't know why your looking to use stainless
it heat's up very Quickly but take's forever to
cool down. Also can Warp easily if it get's to
hot. Grow's allot with heat which may not
be good with that fitted bearing. Only thing
that seems to be in your favor is the internal
water cooling.

Titanium is alot like aluminum, we use Titanium
at work allot because you can cycle the temps
up and down very quickly.

Nice and light, machines better than stainless,
very strong, and you can polish it to a mirror
finish also.

Good Luck
Cougarman

Now, wouldn't that just be trick. Polished titanium. That even sounds cool.

Titanium
 

Machine's really nice to, especially if your using
coolant while cutting it.

Stainless is a beast it's doable, but even with
coolant it's hard on everthing. Hard on cutter's,
your grinding disc, etc.

It's a very tough material, but yet very soft.
You need to really know your Stainless grades
so you can buy the right material for your
application. As with any metal !


Cougarman

**It's a very tough material, but yet very soft. **

"Soft" is not the right word. Gummy, Stringy, those are better descriptors.

And if the hone on your cutting edge isn't prepped properly, and you aren't using the right coolant, and are using too fast of a spindle speed or too slow of a feedrate, you will end up throwing more tools at it than you'd imagine. Not too difficult, though, if you got a handle on the above variables.

Still don't think it compares favorably with aluminum.

You guys crack me up. Machining stainless is no different than any other metal, as long as you use the right tooling, coolant, speeds and feeds. I grew up machining before CNC’s and can still remember grinding my own tool bits. With today’s equipment, and a little knowledge, it’s not that difficult. (75% of what I do is stainless).
I checked on the cost of titanium, "just" the material for "one" bravo cap is $840.00. I am machining a production run of aluminum caps this week. Anybody who wants to give a deposit for some out of titanium I’ll have them done in about 4 weeks. I'm going to make a set for myself, maybe even a set of trim tabs to go along. I'll post some pics. soon.

RedDog382, Why are you replacing your Billet Marine caps?

** Machining stainless is no different than any other metal, as long as you use the right tooling, coolant, speeds and feeds. **

Uhh, isn't that the case with ANY material?
For the "apprentice class" machinist though (including weekend machinists), stainless is a bit confusing. While you know and I know that you can hand grind just about any drill to perform satisfactorily with the "right" feeds and speeds, I've seen a LOT of guys (in my shop and in other shops) weld a lot of drill bits to stainless bar stock. I can't imagine that you haven't seen it also.

For the purposes of this thread, though, it may be a little nuts to harp on the different machinability issues of stainless versus other metals since nobody is acting like they are wanting to hacksaw a pair of caps out themselves.

Looking forward to your pix.

rbtnt,

Just discovered an impending massive melt-down in one of my drives. The boat was purchased without power, previously rigged with 950 H.P. motors, XR uppers (the fourth set of drives in 75 hours), and standard Bravo lowers. Lube was almost black, burnt, full of metal shavings. Vertical and prop shafts were twisted. There is some checking on the race of the top cap.

I am upgrading the entire drive with Max Machine Worx, including their power tower in the upper, XR lower with torsional alloy shafts, and top cap made of 6061-T6 mentioned by mcollinstn earlier. My drive showers are rigged to the Latham steering plates, so the water cooled passages on the Billet Marine cap are not being used.

I think the Billet Marine caps are a major improvement over stock, but I believe the Max caps are stronger and better.

I don't know what they sell for new, but I would make someone a good deal on them if interested.

Chris

I may be interested in the pair depending on the definition of "good deal".

mc