Big mag drill cutters

[fizzy]

I have a Rotobroach Panther which is brilliant.
It states capacity up to 40mm. I have used 42mm no problem at all. Could I go a lot bigger - say 60mm or even 80mm?
Drilling mild steel - about 8mm thick.
Obviously the slowest speed and plenty of soluble cutting oil.
I need to drill out the webs on I beams to lighten them.
Or would I be better off with hole saws?

 

[slim_boy_fat]

Plasma

 

[123hotchef]

I have used 70mm on my one with only 1 speed, it was a bit fast for the cutter really but it did no harm.

 

[Robbie260]

I have a Rotobroach Panther which is brilliant.
It states capacity up to 40mm. I have used 42mm no problem at all. Could I go a lot bigger - say 60mm or even 80mm?
Drilling mild steel - about 8mm thick.
Obviously the slowest speed and plenty of soluble cutting oil.
I need to drill out the webs on I beams to lighten them.
Or would I be better off with hole saws?

Would depend on the cutter and how thick the material your wanting to drill is and weather there is sufficient clearance between the chuck and the magnet too allow such a cutter to fit. Rotabroaches are pretty solid units have seen them mercilessly abused, dropped off scaffold, drowned, run over etc etc and still keep on working. So I don’t believe an over size cutter would wreck one just take it really slow plenty of cutting fluid make sure it’s sharp and if it stalls don’t let it sit there not turning switch it off. By a good quality cutter as you will still need it even if you find you have to hire a bigger one.

 

[Kram]

I was looking at mag drills, most dont appear to have clearance for the bigger cutters?

Holesaws can work but they dont have chip clearance and need to be peck drilled. They are really intended for wood and thin sheet metal.

I guess 8mm is too thick for one of those hydrualic hole punches?

 

[fizzy]

Good point about the clearance - will have to check mine.
The drill itself sits nicely in the channel.
Really is an excellent bit of kit - and British made! Noisy though.

 

[fizzy]

Plasma

My plasma cutting skills are seriously lacking. Or maybe it's my cheap Chinese Cut 50 thing.

 

[gaz1]

My plasma cutting skills are seriously lacking. Or maybe it's my cheap Chinese Cut 50 thing.

come off it its you

to be honest id cut a hole and swap to plasma if im doing alot of cut outs in ibeams to reduce weight

 

[Kram]

You need practise then plasma if you have one, sounds ideal for it.

 

[fizzy]

How do you cut a nice round hole in an I beam with a plasma cutter?
I know you can get those compass things but no room for them.

 

[MattH]

My plasma cutting skills are seriously lacking. Or maybe it's my cheap Chinese Cut 50 thing.

Cut a small thin ply template out that sits in the web and has an oversized hole that you can run the edge of the nozzle around.

 

[fizzy]

I just worked out how much weight I would save on my 3.5 ton trailer.
25kg. Hardly worth all the effort.

 

[Munkul]

Half the reason why the clearance is limited on a rotabroach - say a nominal 40mm capacity - is exactly to stop you putting a huge oversize cutter in the forces are way higher. Even a 40mm cutter in a panther/commando 40 is a bit much, brand new its not bad but once it gets some wear and maybe a damaged tooth... it starts wandering, and it will flex the tool something rotten.

I'd make a guide of some form, and plasma it. Faster and easier.

 

[Agroshield]

If you go too mad, I'd be worried about the magnet letting go. It holds with a certain force. The cutter requires a certain pressure to encourage it to remove material. Bigger cutter, larger perimeter, larger force needed to achieve the same cutting pressure, magnet has to work harder. Couple that with a thin web which is not helping the adhesion and it might be dicey.

 

[Kayos]

My sds is rated to 22mm in masonry, regularly used to drill 30mm
My combi drill is rated to 35mm in wood, I use my 127mm holesaw often

Manufacturers are just over cautious.....

 

[MetalMonkey]

My combi drill is rated to 35mm in wood, I use my 127mm holesaw often

Maximum drill capacity refers to the diameter of a drill bit, it is just a reference for torque – obviously the load on a hole saw is completely different and the diameter can't be directly equated.

 

[brightspark]

Maximum drill capacity refers to the diameter of a drill bit, it is just a reference for torque – obviously the load on a hole saw is completely different and the diameter can't be directly equated.

verry true i was cutting some 50mm holes on some sheet steel using the pillar drill and hole saw and it didnt like it

 

[nickk]

Other thing to remember,use proper cutting oil,not soluble oil,that’s more for washing the kerf clear and cooling.

 

[Justme]

Other thing to remember,use proper cutting oil,not soluble oil,that’s more for washing the kerf clear and cooling.

Is it not the same stuff but a different % mix?

Sure the last gallon I bought have a few ratios for different use.

 

[nickk]

Cutting oil is quite a refined and engineered chemical with a lot of clever additives that considerably aid cutting,especially on tougher metals.