[bingles104]

Hey guys, I'm in the process of modifying my '92 to fit a custom subframe and have a question about modifying the frame "wings". I want to reduce their overall presence to flow with the look of the bike, but have read varying advice on cutting aluminum. Given that it is on a bike, a circular or skillsaw is out of the question. I have read that using a sawzall with a carbide tip blade, dipped in wax (to prevent gumming) may work, but I have no experience with this particular application on aluminum. I am trying to achieve the most precise cut as possible, but understand I will have to smooth it out and refine. Has anyone done this before or recommend the best way to go about doing this? I have seen various levels of this done so I know its possible to an extent (see pics below). Any advice would be greatly appreciated!


Here are the lines I'm looking at cutting...

Other Examples

 

[SEBSPEED]

Angle grinder and a cutoff wheel will make quick work of that.

 

[makenzie71]

I would personally be pretty reluctant to take an angle grinder to that. Too much potential for breaking the blade.

I would suggest not doing it at all, really. However, if you are going to do it the best way will be with a low tooth count reciprocating saw and slow cutting. Slow on both blade speed and forward motion. And be sure to take numerous breaks to keep cutting temperatures down and to keep the cutting area clean.

 

[Mongoose]

its cast aluminum... its softer than wood.. hack it off just make sure there's enough meat for the shock mount.

 

[sebwiers]

Its not that much cutting. If there's room to work, just use a hacksaw. Hand powered tools are often ignored, but work great for some jobs. Its a bit more work using hand tools, but its also harder to accidentally fuck something up real bad.

 

[bingles104]

Angle grinder and a cutoff wheel will make quick work of that.

Thanks, that was my initial thought, but was a little worried given some of the advice I've heard. Def a fast cut though for sure!

I would personally be pretty reluctant to take an angle grinder to that. Too much potential for breaking the blade.

I would suggest not doing it at all, really. However, if you are going to do it the best way will be with a low tooth count reciprocating saw and slow cutting. Slow on both blade speed and forward motion. And be sure to take numerous breaks to keep cutting temperatures down and to keep the cutting area clean.

That is what I have heard as well - avoid heating it up by going slow.

Its not that much cutting. If there's room to work, just use a hacksaw. Hand powered tools are often ignored, but work great for some jobs. Its a bit more work using hand tools, but its also harder to accidentally fuck something up real bad.

I think I may go this route...I like the idea of not accidentally botching the whole thing as easily with something powered and 32-tooth hacksaw blades are dirt cheap.

 

[yantosh]

i cut welded on ally subframes with a hacksaw, they tend to spring and grab . but as Seb says, cut off disc , just pop a decent face guard on

 

[bingles104]

i cut welded on ally subframes with a hacksaw, they tend to spring and grab . but as Seb says, cut off disc , just pop a decent face guard on

So you recommend using the angle grinder? It didn't gum up on you at all?

 

[yantosh]

it can do , hacksaw and a sanding disc to clean up wouldn't take too long , suck it and see ? possibly get discs made for cutting ally

http://www.ebay.co.uk/itm/5-X-DEWAL...M-CUTTING-GRINDER-DISCS-AC46TBF-/391697524051

 

[XxGRYMMxX]

ive used my angle grinder to cut alu before too, just go slow and dont press hard. itll grab more the hotter/softer it gets.

 

[titan]

grinder, nice thin blade avoid snatching the blade should be fine as everyone else has said wear safety gear just incase.

thinner blades tend not to carry through the air as much if they break off thicker blade can hurt a lot.

 

[shinyribs]

Is aluminum known for making cutoff discs snap and fly apart? When did that start? Never broke one in the past 20 yrs.

Everything mentioned in the thread will cut it just fine.

Fuck that bit about dipping sawzall blades in melted wax. That would last all of 1 blade stroke and sounds incredibly complicated for no reason at all. Just use oil if you're concerned with clogging.

 

[makenzie71]

A cutting disc will cut it just fine...and it's not that aluminum likes to grab graphite discs...but a cut like that would require a very steady and firm hand. Also, a cut off wheel will make a radius cut. It's not that it won't work, but it's not the right tool for the job. The correct tool for the job is a straight, low TPI saw.

 

[MikeGyver]

Never broke one in the past 20 yrs.

You're doing it wrong.

 

[HickLife]

Is aluminum known for making cutoff discs snap and fly apart? When did that start? Never broke one in the past 20 yrs.

Everything mentioned in the thread will cut it just fine.

Fuck that bit about dipping sawzall blades in melted wax. That would last all of 1 blade stroke and sounds incredibly complicated for no reason at all. Just use oil if you're concerned with clogging.

I've heard of the aluminum clogging grinding disks, then heating up and causing the aluminum to expand and the disk blowing apart. Idk how true it is though, never seen it myself


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[Mongoose]

I've heard of the aluminum clogging grinding disks, then heating up and causing the aluminum to expand and the disk blowing apart. Idk how true it is though, never seen it myself


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i think it's more pressure related.. disks get loaded up real quick and stop cutting as well..

ive never been a plow a disk metal kinda guy, but i know there are people who do.. in steel i suppose its not as big of a deal as it'll keep cutting but alum.. it wont want to and prob goes pop.

 

[shinyribs]

Grinding discs are one thing, but Seb was talking about using a cutoff wheel.


You can't grind aluminum. File or sand.

 

[SEBSPEED]

Well, you're not grinding, you're cutting... so you use a thin cutoff disc on the grinder. I have a small bosch grinder that's been my go-to for zipping off all sorts of stuff from carbon fiber to 2" thick cast AL frame sections... all done with cheap 4.5" harbor freight thin metal cutoff discs.

I do have a pair of steady meat paws tho

 

[SEBSPEED]

Hacksaw will cut that with ease, but I'd have an easier time cutting a straight line with my cut off wheel.

 

[mcantar]

Angle grinder gets my vote, too easy for blade to wander with a hacksaw or sawzall... not to mention the back clearance needed to use them well.
Then finish out the shape with a hand file and then hit it with a DA.


If you're that worried about discs grenading, well, quit being a pussy. Replace the disc and continue working.
99.9% of the time it happens, it's from misuse of the tool.