Need advice on cutting metal

[priobe]

Hello all,

I am in the process of adapting the Kirkham ebrake to my non Kirkham replica.

I currently have a bracket that supports my Wilwood caliper on to my spindle with the manual Wilwood crappy caliper. Rather than cutting my bracket to make it fit, I would like to make a new bracket. By doing this in case something was to go wrong I could always go back to my oringinal setup.


The metal is approximatly 3/8 in. thick. This is not a complex piece to make ecept I dont know what would be the best way to cut the metal because it has a slight curve to it.

What tool other than a plasma cutter would cut such metal.

Also, how thick would the bracket have to be if I used Aluminum.

[lineslinger]

Can you post a picture of the bracket? The fact that it supports a brake caliper mandates some specific attention......
I use angle grinders, cutoff saws, sawzalls, cutting torch, mill, so much depends on the configuration of the piece and the metallic hardness required.

[Paul F]

'Slinger is right. Let's see a picture and we need to know what kind of metal and what kind of cut is required. Aluminum gums up a lot of tools. We also need to know what tools you have so we can suggest what to use or buy.

If it is steel, the lowest budget solution if you don't have any tools is an angle grinder with cutoff wheel. $15-$20 at Harbor Freight. Aluminum will gum up the angle grinder, but it might work depending upon cut.

[priobe]

Here are some pics I have in the gallery. I hope you can get an understanding by this

[Paul F]

So you want to make the red item from a piece of plate and weld on some other pieces?

[Ralphy]

My guess is your talking of going old school on this, or caveman style. Wow your doing a large inside radius. You can layout your outside dimensions. Then drill holes around the perimeter. After the holes you can bandsaw from hole to hole. You can turn a bandsaw blade some, by backing up and forcing the blade to one side. Once finished you can belt sand the contour. The Triangled area also can be drilled, then if you have a bandsaw blade welder you can put the blade through the holes, weld the blade to length, etc...
Next best would be if you had access to a Bridgeport type mill. You could hold the part ridged, then punch holes along that nasty inside radius closer.

That part requires a bit of work even at a machine shop.

I used to surface grind aluminum, we used Crisco grease, the aluminum goes into the grease and not the wheel, however that is not extreme grinding.

Ralphy

[mickmate]

If you're using aluminum instead of steel rule of thumb is to make it half the original thickness again. 3/8 plate steel would be replaced with 9/16 aluminum. Use a good alloy whether it's steel or ally. CRC 5.56 is a really good cutting oil for aluminum or kerosene is the old school solution. You can cut a lot of metal with a cutoff wheel in a 4" grinder, I like Pferd wheels as they give a good balance between cutting and wearing. A sawzall would also work well on plate like that.

[Ralphy]

mickmate,
Damn your right a sawzall would be a great idea. That to me is a wonder tool! If I had my choice I would make it out of aluminum. A trick I came up with, is to take about three or four cut off wheels and stack them to make a wider wheel. Then dress the wheels with a stone or as we call it a Dog Turd.

[mickmate]

Just match the blade to the material type and thickness, again rule of thumb is at least 4 teeth in contact with the metal being cut.

[RallySnake]

Priobe,

Using aluminum to make a brake bracket is a VERY bad idea.

I have had good results cutting steel of this size with a saber saw. You will need a lot of blades and a lot of patience.

Paul

[mickmate]

Interesting that they make most new calipers out of aluminum, why not the brackets?

[priobe]

Originally Posted by RallySnake

Priobe,

Using aluminum to make a brake bracket is a VERY bad idea.

I have had good results cutting steel of this size with a saber saw. You will need a lot of blades and a lot of patience.

Paul

I guess I could try with the Sabre saw.

I did not think it would cut through the steel so I was thinking maybe aluminum

[Paul F]

It will cut, but you will need a lot of expensive blades and time with that thickness. Sawzall might work through it quicker, but you have no bend radius. Ralphy's suggestion of drilling and cutting with the angle grinder will be faster. Especially on the outside cuts. Finish grinding the inside diameters with a carbide bit and then sand. A lot of work without a bandsaw or plasma, but it can be done.

If that's not for you, then go to the local machine shop. They can program that into the CNC mill and charge you $150 to cut the shape and inside openings. You'll have a nice clean part. You finish it by drilling the holes.

[mickmate]

Aluminum will be fine and easier to cut. If someone will let you use a bandsaw even a wood one will go through ally that would be relatively easy.

[lineslinger]

You know, I admire you for analyzing how to build your own piece, but this one might dictate a time to buck up and and by a manufactured piece. By the time you get the tooling together and perform all the layout, as well as actually try and fabricate the bracket you need......its going to take a long time.

The exacting alignment needed, and it is a brake piece, will be a big deal in terms of getting the proper alignment for fasteners, drilling, redrilling, honing, filing, etc.
You will be getting a serious workout climbing up and down checking the fitting and then making sure all the alignments are correct and the piece is built in the manner it needs to be in terms of strength and application.
Not trying to dissuade you, but more of a been there done that scenario.

[427mudflap]

If you think you can make one you should be able to make a drawing of it (remember you might have left and right parts) then layout and make a cardboard part, see if it fits, if so take your drawing to a small shop that does laser cutting. Get a quote, if its to high offer them less.
If you don't have a band saw don't try it.

[kobrabytes]

Originally Posted by RallySnake

Priobe,

Using aluminum to make a brake bracket is a VERY bad idea.

I have had good results cutting steel of this size with a saber saw. You will need a lot of blades and a lot of patience.

Paul

Odd, nearly all my suspension is aluminum!

[David Biele]

Ralphy,

I agree with Paul F, find a local machine shop with a CNC and talk with the owner and pay him cash. I own a fairly large machine shop and when people talk with me and need help I usually help them and I don't charge standard rates. We call it a 'G' job.

David

[Ralphy]

David,

Sure cheating always works! lol Just kidding, I figured he was looking for ways to make this part at home on the cheap. Giving him 10 ways to skin a cat by all allows him to look into his bag of tricks (tools). The issue I might be seeing is that the mounting holes appear to be countersunk. This is not a simple garage project by no means.

I know all about G jobs. I have worked most my life as a machinist and I do have access to 3 axis machines. Man that is great that you cut hobbyists some slack. I think you should be awarded 500 Club Cobra points.

[LMH]

I use a 4.5" grinder with a cut-off wheel for a lot of my cuts. Bandsaw would be better if you have some curve to it.
Larry