Cutting stainless

[AnthonyExmouth]

What would be my best option for cutting nice curves in 2-15mm 316 stainless? I make up parts for my boat at had to knock up a new pintle and gudgeon at the weekend. I did the best I could to get a semi circle cut but it's really rubbish. It'll work but would have been nice to get a better radius on it.

 

[Morrisman]

Some sort of laser cutting would be the best way, at that thickness.

 

[Agroshield]

Please clarify that you mean a minimum of 2mm and a maximum of 15mm. That is a difference of 7 1/2 times in thickness. It is unlikely that whatever works well on 2mm will work well on 15mm. Hence, you might need at least two options, one for the thinner end and one for the thicker stuff.

Is it a tool you want to do the work yourself or a process (cnc plasma, cnc laser, cnc waterjet) that will produce the desired results?

 

[AnthonyExmouth]

Some sort of laser cutting would be the best way, at that thickness.

The 16mm would be rare. Mostly 3-5mm. Only reason I had 15mm this time was because I sandwiched some 10mm flat between some 3mm angle to beef up the the fitting. Could have cut it before welding it together.

 

[AnthonyExmouth]

Please clarify that you mean a minimum of 2mm and a maximum of 15mm. That is a difference of 7 1/2 times in thickness. It is unlikely that whatever works well on 2mm will work well on 15mm. Hence, you might need at least two options, one for the thinner end and one for the thicker stuff.

Is it a tool you want to do the work yourself or a process (cnc plasma, cnc laser, cnc waterjet) that will produce the desired results?

Just something for myself. It's mostly 3-5mm I use but sometimes beefed up with some thicker flat bar.

 

[Kram]

Plasma is a good option. With a radius attachement or guide template it can get very neat cuts.

 

[Erie Fred]

What are your skills to drawing the parts in CAD ?

 

[AnthonyExmouth]

What are your skills to drawing the parts in CAD ?

It's really not that kind thing I need. It's more about making custom boat parts and just being able to round out things to make them look nicer. Not precision parts.

 

[Erie Fred]

It's really not that kind thing I need. It's more about making custom boat parts and just being able to round out things to make them look nicer. Not precision parts.

I didn't ask that.

 

[AnthonyExmouth]

I didn't ask that.

I've never had to make precise drawings.

 

[Erie Fred]

I've never had to make precise drawings.

So be it.

 

[Agroshield]

With a radius attachment or guide template it can get very neat cuts.

As above. And you can make the template out of plywood or MDF. Draw the curve with a pair of compasses. Jigsaw roughly to size, sand so that half the line disappears. That would be good if you have a curve blending into a straight or a curve that changes direction or radius.

It might be good to say what size of radius you might use - a 6mm rounding over of a corner is different to a 300mm curve.

 

[AnthonyExmouth]

As above. And you can make the template out of plywood or MDF. Draw the curve with a pair of compasses. Jigsaw roughly to size, sand so that half the line disappears. That would be good if you have a curve blending into a straight or a curve that changes direction or radius.

It might be good to say what size of radius you might use - a 6mm rounding over of a corner is different to a 300mm curve.

In this situation it was some 50mm angle 100mm long that I wanted to make a sort of semi circle cut on one half so when it was bolted to the transom it had a full leg bolted and the semi circle sticking out so it looked a bit nicer.

 

[Misterg]

just being able to round out things to make them look nicer. Not precision parts.

Belt sander / linisher is your friend in that case. Get it as close as you can with a grinder (or whatever) first.

 

[AnthonyExmouth]

Belt sander / linisher is your friend in that case. Get it as close as you can with a grinder (or whatever) first.

How does one of those cope with stainless? I did wonder about one of those. I would like one.

 

[Misterg]

How does one of those cope with stainless?

Fine, if you get a decent quality belt. (You may want to keep a belt(s) just for stainless to avoid possible problems with rust staining.)

 

[RichardM]

Jigsaw and a pack of these:

https://www.screwfix.com/p/bosch-expert-t118ahm-sheet-stainless-steel-jigsaw-blades-83mm-3-pack/933pf

 

[AnthonyExmouth]

Jigsaw and a pack of these:

https://www.screwfix.com/p/bosch-expert-t118ahm-sheet-stainless-steel-jigsaw-blades-83mm-3-pack/933pf

I've tried those in the past and not with much success. I ended up buying a band saw which works well but only for straight cuts.

 

[Barking Mat]

Once you've plasma'd stainless it will be well difficult to grind to perfection. Get it laser cut.

 

[AnthonyExmouth]

Once you've plasma'd stainless it will be well difficult to grind to perfection. Get it laser cut.

Most of the things I do are making good or making replacement parts on the day for working boats. Don't have the time to send off for laser cut parts and as much as I'd love a CNC laser it's a little out of my reach. I'm liking the rough cut with grinder and then belt sander idea if that's going to work.