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Discussion Starter #1
I would love to be able to build this:
Styrene Cab

In brass rather that styrene...I think I could handle the soldering, the only thing that prevents me from building a cab in brass is "how to cut the brass sheet??"  /DesktopModules/NTForums/themes/mls/emoticons/blink.gif


I use the "score and snap" method for styrene..and a good old-fashioned x-acto knife..but how do you cut nice straight lines in brass sheet?


(I would need to work with 1mm and 0.5mm thick brass for this particular project)


hand-sawing is no good..I cant cut very straight by hand.."score and snap" wont work..x-acto blade and a ruler wont work..


metal shears are no good because they bend/warp/distort the sheet like crazy as you cut..


what to use then??


thanks,


Scot


 


 
 

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There are a number of things. Dremel cut-off wheels would be at the top of the list. Nibblers help. You can get shears that are a little finger that doesn't warp so bad. You can also get a number of small rotary saws. Then comes the machine tools. Fine toothed blades in table saws, band saws, then comes milling machines. We've even used CNC water jets.

John
 

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I am afraid there is nothing for you do but dig out a 32 TPI hack saw and a steady hand...

regards

ralph
 

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If you use a good quality pair of snips and cut so that the waste is to the underside (usually the right of the shears) then the part you are left with is usualy straight.

That has been my experiance.

Regards Rod
 

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Discussion Starter #6

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A small variable speed bandsaw equiped with a metal cutting blade is wonderful


for this kind of work...


Paul R...
 

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My mini table saw might work!  /DesktopModules/NTForums/themes/mls/emoticons/shocked.gif


This saw:


http://gold.mylargescale.com/scottychaos/On2/On2-coach-page2.html


might work for me! I just tested it on some scrap brass.


the "diamond blade", same one I used for the styrene,


can cut through 1mm thick brass..slowly..although I dont think it would do well for anything thicker.


it gets REALLY hot..(the brass that is being cut) ..have to wear gloves while holding it..


and the blade will probably dull quickly..but it might do the job in this case, for such a small cab..


Dont need the speed controller like you do for the styrene..the speed controller is to keep the plastic from melting.


Im going to buy some brass and try it out!


Scot


 


 


 
 

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Here's an idea, Scot:


Invert your saber saw under a cobbled-up table of some kind, with the blade protruding upward through the table top.  Use a very fine-tooth metal cutting blade and set the "orbital" motion of the blade to zero, if it has that adjustment.  Slow the speed way down with one of the cheap router speed control units from Harbor Freight.  Cut just on the waste side of your cutting lines and hand finish to the line with a fine file.


For internal openings, drill one or more pilot holes big enough to admit the saber saw blade.


The table top should be as close to "zero clearance" as possible.  Failing that, tape your brass blank to thin plywood and cut both at once.


GO SLOWLY!


Regards, Dawg :cool:


P.S. Don't try to cut thin brass on your table saw.  Very risky (IMHO).  A very-fine toothed blade in a slow-running bandsaw will work, but won't do internal cuts, like windows.  


 
 

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Discussion Starter #10
Posted By dawgnabbit on 01/05/2008 3:56 PM


Here's an idea, Scot:


Invert your saber saw under a cobbled-up table of some kind, with the blade protruding upward through the table top.  Use a very fine-tooth metal cutting blade and set the "orbital" motion of the blade to zero, if it has that adjustment.  Slow the speed way down with one of the cheap router speed control units from Harbor Freight.  Cut just on the waste side of your cutting lines and hand finish to the line with a fine file.


For internal openings, drill one or more pilot holes big enough to admit the saber saw blade.


The table top should be as close to "zero clearance" as possible.  Failing that, tape your brass blank to thin plywood and cut both at once.


GO SLOWLY!


Regards, Dawg :cool:


P.S. Don't try to cut thin brass on your table saw.  Very risky (IMHO).  A very-fine toothed blade in a slow-running bandsaw will work, but won't do internal cuts, like windows.  


 



 


 


Thanks Dawg.. "my" saber saw?? I wasnt aware I had one! ;) (Actually..I dont..not even sure what a sabre saw is)
P.S. Don't try to cut thin brass on your table saw. Very risky (IMHO)


why? what risk are you thinking of? the blade spins downward at the front..so as you feed material to the front of the blade, the spinning balde is forcing material down, into the table, not up..the only risk I can see over cutting styrene or wood is heat..the metal gets hot! other than that, how is it any different than using that saw to cut styrene or wood? (it goes without saying, but its good to say anyway, that safety glasses are ALWAYS worn! ;)


thanks, Scot
 

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Scot,


It's not the "down at front" that's bad, it's the "up at back."  If the workpiece contacts the rear of the spinning blade, it can pick it up and throw it back at you.  This is called "kickback."  Thin sheet metal can vibrate and distort during cutting and sooner or later will get into the wrong part of the blade.  Brass is especially "grabby" and prone to this.


You don't want thin sheets of brass coming back at you at speed.  Think ninja...


You probably don't have a saber saw then, but they're handy and not too expensive.  Sometimes called "jigsaws", they're just  hand-held reciprocating saws designed for cutting curves in thin sheets (of wood, metal, what have you).  The attached picture shows one.


Regards, Dawg ;)


P.S.  the diamond abrasive blade may be a little safer, but the heat may distort your workpiece.  I wouldn't be inclined to do it that way myself, but if it works for you...well...that's what counts, I guess.  Let us know how you make out.
 

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Discussion Starter #12
Dawg,


thanks for the advice on the "kickback"..definately something too keep in mind!


but I think in my case it wont be an issue..


im building an On2 scale cab..small..the material being cut wont even reach all the way to the backside of the blade.


maximum cut length will be 1.5"..and its 3" from the front to the rear of the spinning blade.


but still.. I totally understand what you mean by "think ninja"../DesktopModules/NTForums/themes/mls/emoticons/blink.gif that would not be fun..


If I do end up using this saw for brass (not sure yet, might stick with styrene) I will rig up a rear safety sheild..so if anything does get caught and flung upward, it will hit the shield before it hits me..


thanks,


Scot


 
 

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As far as straight lines go, you will probably have to dress them with a file, when the cutting is done.

Files are strange - you HAVE to have a new one to do anything on brass. A new file cuts brass like a hot knife through butter. An old file just rubs and rubs but will hardly remove any brass, though it works fine on steel.

So, go buy a couple of new files and mark your old ones, if necessary, so you will remember to only use them on steel. You'll find working with brass is a treat with new files.
 

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Scot, get a carbide blade for your mini saw I use one on my table saw. But the best tool I use is a bandsaw with a metal cutting blade. Mini saw blade are available from Mirco -Mark.  GOOD LUCK


Dave
 

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Scot
Maybe the following article in PDF format that I made from Larry Mosher's MLS topics when he built the Gilpin Gold Tram car, will be of help to you. If I remember correctly he mentioned that the bench shear that he purchased cost around $60US.
Gilpin Gold Tram Car
Larry Mosher

(File Size - 1.8MB)
 

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Hi Scot,


One thing I've been using quite a bit to make square/rectangular holes in brass sheet stock is a nibbling cutter available from MicroMark as their part number 81477.  I drill a hole large enough to insert the bit through and then cut close to the scribed lines.  I make a point of going just a bit shy so that I can clean up any irregularities with a file.





Llyn
 

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Scot,
In looking at your proposed project, you say you are okay with soldering. Have you considered fabricating it up from strip stock? That is available from most hobby shops and you won't need a saw. Just use a Dremel cut-off wheel to cut the pieces. Clamp them down to a stone tile or ceramic foam and have at it. Fill the joints with solder and file smooth.
John
 

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Scot,

If you intend to do a lot of brass fabrication in the future, you might want to consider getting a small sheet metal shear. Once the blade is adjusted, it is possible to equip them with highly accurate (=/- 0.005") back gauges to make repetitively cutting strips from sheet stock to high tolerance quite easy.

Grizzly sells several small shears that would be more than adequate for this type of modeling. G6089 would be a great choice as it is a triple combination (shear, brake and slip roll) machine - ideal for modeling.

Brian
 

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Discussion Starter #20
Posted By John McGuyer on 01/06/2008 2:12 PM
Scot,
In looking at your proposed project, you say you are okay with soldering. Have you considered fabricating it up from strip stock? That is available from most hobby shops and you won't need a saw. Just use a Dremel cut-off wheel to cut the pieces. Clamp them down to a stone tile or ceramic foam and have at it. Fill the joints with solder and file smooth.
John


 
John, thats a very good idea! :) that could work..im going to explore that idea more! thanks, Scot
 
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