Cutting a sprocket from 30mm steel - tips?

[AD80]

Hey folks,

I have a sprocket for a trench cutter to make out of 30mm plate - The mechanised pierce of the hypertherm 125 is 25mm, so I'll have to start from the edge to cut the outside of the sprocket. It has a 50mm hole in the centre to be located on a shaft and welded - I guess I'll need to drill a hole for it to starts from.

What tips does everyone have - this is the thickest material I have cut to date!

Cheers,
Ant.

[plasmanewbie]

well i'm no pro but do test cuts in the known waste area of the material to practice that 50mm hole so you can get your speed down to where it will cut square as possible for that shaft to be welded. I would do a dry run also and pause the machine at both pierce points and just to a quick test fire of the torch to mark the locations of the holes to be drilled for the edge starts. Don't test fire too long or it will harden the surface making it tougher to drill. Best of luck!!

[AD80]

My first shot at edge starting on thick material

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[_Ogre]

nice cut quality!

[AD80]

Yes, I’m very pleased with the outcome! Great cut quality and it was all done using hypertherms recomended book settings.
As it was my first time doing an edge start etc - I contacted Swiftcut for advice, they kindly offered to send an engineer to my premises and gave me half a days training! Great service!

The picture shows the new sprocket on the old shaft and how worn it the old one was! This one will be welded to a new shaft. I was also impressed how true the hole was condsodering it was 50mm diameter in 30mm thick material.

BE3553BD-F101-43FB-BC01-C1B23BE7F90E.jpeg