How to make this?

[RWD3M]

Hi chaps,

I need to make this:

80 x 40 x 3 box with a couple of 22 x 16 tubes welded inside, then a slot through the whole lot. Getting the tubes into the box are straightforward but the slot is perplexing me just a little.

The slot is about 1/2" wide and about an inch in length. I have a drill press and a small mill (EMCO FB2 clone).

In my head I'm thinking once the tubes are welded in place, punch a 1/2" drill through whole lot on my pillar drill, and then use the mill to turn the hole into a slot. Am I that far off?

I've had a little play with the mill on just a piece of 22mm tubing and TBH, it didn't seem like it wanted to make the holes on it's own. This is likely because I really don't know what I'm doing with it and/or I'm using the wrong bits?

Any light you can shed would be most gratefully received.

 

[RWD3M]

Hmm.. not sure that attachment is going to work. It should be a 3d object that can be opened with a 3d viewer.

If it doesn't perhaps someone can let me know how to upload it?

 

[Mark 2]

Obj and the relevant mtl file all snuggly zipped up.
A sketch might suffice, have you a fag packet to hand?

 

[bourbon]

CAD please. (that's cardboard aided design. aka back of a fag packet)

 

[m_c]

Is it meant to be that big, or have I imported it in the wrong units?

 

[addjunkie]

Skip driiling on a drill, drill the holes in the mill, itll save setup time. Slot drill then a milling cutter! Or just drill two holes and use a file

 

[Brad93]

Two flute centre cutting endmill. Punch through and then make the slot in one hit. Plenty of oil.

 

[raph68]

You’re not far off at all. Drill press first is what gets people into trouble. Clamp it once on the mill, spot drill, then use a centre-cutting 2-flute end mill to plunge and slot. If it felt like the mill didn’t want to cut before, that’s almost always cutter choice or speed, not you.

 

[RWD3M]

View attachment 524171

Is it meant to be that big, or have I imported it in the wrong units?

Probably yes. The box section is 40mm x 80mm.

Thatis actually just the end section of what I'm fabricating which is overall, 700mm x 300mm x 80mm.

I'll be making the part with the slots in it before welding it to the two bits of box section at the ends so a piece 220 x 80 x 40.

 

[RWD3M]

Two flute centre cutting endmill. Punch through and then make the slot in one hit. Plenty of oil.

You’re not far off at all. Drill press first is what gets people into trouble. Clamp it once on the mill, spot drill, then use a centre-cutting 2-flute end mill to plunge and slot. If it felt like the mill didn’t want to cut before, that’s almost always cutter choice or speed, not you.

I'm pretty sure that's not what I was using. I may not have one so will endeavour to find one. Thanks chaps!