Routing mild steel in a 1/4" router

[Pykie]

Hey guys, was wondering if anyone could point me in the direction of a carbide 1/4" router bit that is able to cut mild steel?

It's for installing fire doors, there's a mild steel cap about 5mm under the door edge that you have to get through to install mortise locks etc, they're always a pain in the butt and even with a spade bit/hole saw, they always leave bumps that can't be filed back that grab the spade bits etc and that effect the lock body.

Was planning on using a router bit in a jig to cut the mild steel clean and perfect to the lock body and then continue with the mortise.

Anyone recommend a good bit?

 

[Bohdan]

Have you considered using a TC burr as these are designed to cut steel at high RPM.

 

[Svar]

Have you considered using a TC burr as these are designed to cut steel at high RPM.

I agree. I rout steel with carbide burrs. They are inexpensive and quite safe. For very small cuts HSS mills also work in hand held router.

 

[Bob D.]

I have no need to do this in the future that I can foresee, but I would
be interested to know how you handled the swarf/chips created by
working with metal. For me I could see possibly aluminum but not steel.
Pat Warner discussed routing aluminum in at least one of his books IIRC.

Did they require any extra or additional action or equipment to collect
or was it more or less the same setup you would use for routing wood.
Is the level of dust collection as good as for wood?

 

[Svar]

I have no need to do this in the future that I can foresee, but I would
be interested to know how you handled the swarf/chips created by
working with metal. For me I could see possibly aluminum but not steel.
Pat Warner discussed routing aluminum in at least one of his books IIRC.

Did they require any extra or additional action or equipment to collect
or was it more or less the same setup you would use for routing wood.
Is the level of dust collection as good as for wood?

Same setup as for wood. Metal shavings are heavy and not easily picked up by the vac, but you are not routing 1"x1" dados in metal either. It's usually very small amount of material, a small bevel, edge cleanup, key hole, etc. It's spark free at 10000 rpm, but you can simply do it without vacuum or start with empty bag if sparks are a concern.
Burr is safer for steel than end mill, but will gum up quickly in aluminum. I don't use woodworking bits for aluminum, they chatter to much.

 

[Svar]

Even though a burr in an air tool runs at high speeds, it performs more of a carving effect than edge chisel or end mill.

If you move your router in a controlled manner using a guide or a jig burr will produce the same effect as mill, just nor as cleanly and efficiently.

 

[Scorpion]

If you have to do it using a router I'd use a router that has rpm control and turn it all the way down.  Use a roughing endmill bit don't get too small.  Too small and you'll risk breaking easily.

You're gonna have to engage the metal slowly and let the mill cut the metal.  Adding pressure to go faster will just increase the risk of breakage.    Metal milling requires a consistent chip load or you'll risk damaging the end mill. 

Don't get carbide.  It's more brittle and really needs a consistent feed rate for the same reason.  Get high speed steel.  Coatings are a waste of money.

It's gonna throw hot chips so short sleeves may not be desirable.  Eye glasses are a must.  May want them to wrap around the sides.  Chips can ricochet.

Me personally...cutting metal with a hand router isn't my favorite idea. 

Sent from my iPhone using Tapatalk Pro

 

[Pykie]

From my experience using a 1940's Logan metal lathe at about 60-180 rpm for mild steel work at 5-10 thousandths at a pass for keyways and other milling work, I couldn't imagine using a router and and bit at high speed on steel, that would scare the heck out of me.

Even though a burr in an air tool runs at high speeds, it performs more of a carving effect than edge chisel or end mill.

Burr seems appropriate. A photo of what you're trying to do always helps. Maybe a stencil and a plasma cutter as an option?

As you can see by the right top image, on fire rated doors the whole door is clad in mild steel then the skin is added to the top. When you need to rout out for mortise locks, auto flush bolts etc, you hit the steel and have to cut it out, easier said that done doing it cleanly.

 

[Bohdan]

[member=59019]Pykie[/member]

Wouldn't putting a hole in the panel breach the fire rating?

 

[overkill19]

I used my 1400 and a Freud wood bit to do this! Worked great... just have to do it in baby steps. For mild steel I'd do the carbide burr

 

[Cheese]

I used my 1400 and a Freud wood bit to do this! Worked great... just have to do it in baby steps.

Hey [member=62698]overkill19[/member] , a couple of questions...

It looks like aluminum, is that correct?

Did you cut the pattern out with a jig or band saw first or did you route the pattern out with the 1400 router?

Did you use round over bits for wood on the edges?

It turned out nice...I like the blending. [big grin]

 

[overkill19]

I used my 1400 and a Freud wood bit to do this! Worked great... just have to do it in baby steps.

Hey [member=62698]overkill19[/member] , a couple of questions...

It looks like aluminum, is that correct?
4"x1/2" aluminum flat bar

Did you cut the pattern out with a jig or band saw first or did you route the pattern out with the 1400 router?

Did you use round over bits for wood on the edges?
Yes with bearing guide

It turned out nice...I like the blending. [big grin]

About 3 different grits of sand paper and 3m 3000 pad and it makes it shine pretty good...enough for back of trailer anyway