Question on cutting the front cap hat channels on mid-90's buses.

[nikitis]

So I'm attempting the roof raise now, and I see where I need to cut and how to cut the front cap hat channels. Mid 90's bus.

This is the only clear photo I can capture of it being cut. You can see he wedged it to protect the back metal, but he plunged pretty wide in order to go all the way through.

My questions are it would seem to be easiest to use a plasma cutter, but he clearly did not. As wide as his cuts were it appears he used an angle grinder but he never specifies what size. Obviously a 4.5 or 5 in grinder won't cut it. It needs to go through the whole hat channel, with a wedge behind to protect and separate the sheet metal from the inner framing metal you have to cut.

Is this the work of a 7 in grinder or was a 9 inch grinder used to make the plunge cut? I need to know what to purchase.

(btw, a multi-tool will not cut this. It will cut through bulk of the hat channel but when you get to the flat parts of the hat channel it only scuffs it, Multi-tools seem to only cut if you are perpendicular to the metal, if the blades edge is parallel, it doesn't cut. I even bought the most expensive blade you can buy for the multi-tool claiming to cut metal and it will but not if it's parallel to the blade.)

 

[skydawg]

Might have been a standard 7 1/4" circular saw with a steel cutting blade. I used one quite a bit and it was surprisingly effective.

PS this is a strange choice of forum location for this question

 

[ewo1]

So I'm attempting the roof raise now, and I see where I need to cut and how to cut the front cap hat channels. Mid 90's bus.

This is the only clear photo I can capture of it being cut. You can see he wedged it to protect the back metal, but he plunged pretty wide in order to go all the way through.
View attachment 1331884


My questions are it would seem to be easiest to use a plasma cutter, but he clearly did not. As wide as his cuts were it appears he used an angle grinder but he never specifies what size. Obviously a 4.5 or 5 in grinder won't cut it. It needs to go through the whole hat channel, with a wedge behind to protect and separate the sheet metal from the inner framing metal you have to cut.

Is this the work of a 7 in grinder or was a 9 inch grinder used to make the plunge cut? I need to know what to purchase.

(btw, a multi-tool will not cut this. It will cut through bulk of the hat channel but when you get to the flat parts of the hat channel it only scuffs it, Multi-tools seem to only cut if you are perpendicular to the metal, if the blades edge is parallel, it doesn't cut. I even bought the most expensive blade you can buy for the multi-tool claiming to cut metal and it will but not if it's parallel to the blade.)

Die grinder and a chisel would work better, no deep cuts to be made. Was there an option to cut it further down and simply ad an extension?

Lastly, why isn't this question part of your build thread ????
Build threads = Motivation !!!

 

[nikitis]

I decided to just use the plasma torch lol. Was quick and easy. Took more prep to remove a few more rivets to bend it out enough to not blow through the skin. It will go to the build thread, just need to compile it.

 

[Mercuric Mind]

If I recall, I ended up using a combination of angle grinder, a sawzall with a multimaterial metal blade, and a BFH and chisel.