hole saws

[old jupiter]

Can't remember ever having hole-sawed stainless, but have drilled and sawed enough to know that besides wanting the right spindle speed and the right coolant, once the tool starts cutting you want to keep the pressure on and never let off until you're through. If you let the tool skid at all instead of making a chip, the stainless work-hardens to a point where you probably will just destroy your tool.

Interested to hear how your effort works out.

[Ltbadd]

Can't remember ever having hole-sawed stainless, but have drilled and sawed enough to know that besides wanting the right spindle speed and the right coolant, once the tool starts cutting you want to keep the pressure on and never let off until you're through. If you let the tool skid at all instead of making a chip, the stainless work-hardens to a point where you probably will just destroy your tool.

Interested to hear how your effort works out.

Good advice, I've used hole saws on .083 wall tube, but never bigger then about 2" dia.

[Ltbadd]

This thread would be much more helpful if one could easily post pics.......what a freekin' joke

[FusionKing]

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Awe.... some!!!!
Now post a pic of the OP's project so we can get a somewhat better idea of the challenges involved.

[Almond farmer]

Most threaded tank fittings have a shoulder that fits into the hole with flange on the external surface. Fillet welded between flange and tank wall.
would take an 8" square carbon steel , 1/8" and cut a hole the correct diameter for the shoulder on a milling machine with rotary turn table clamped to the mill transverse table. Cut a hole using an end mill tool. Probably take an hour.
Then tack weld or epoxy the plate to the end or side of the tank. Bend the plate if installed on the side of the tank , if the tank is round.
drill a small hole in the tank wall close to the plate hole edge and get a fine pitch narrow saw blade and a reciprocating saw and using the plate as a template guide, cut the tank wall. It may take a few blades since material is SS. It would be safe to perform and NOT damage the tank.
remove the template plate and install 6" fitting. Most steel supplies places have 8" square plate, precut.

[FusionKing]

Most threaded tank fittings have a shoulder that fits into the hole with flange on the external surface. Fillet welded between flange and tank wall.
would take an 8" square carbon steel , 1/8" and cut a hole the correct diameter for the shoulder on a milling machine with rotary turn table clamped to the mill transverse table. Cut a hole using an end mill tool. Probably take an hour.
Then tack weld or epoxy the plate to the end or side of the tank. Bend the plate if installed on the side of the tank , if the tank is round.
drill a small hole in the tank wall close to the plate hole edge and get a fine pitch narrow saw blade and a reciprocating saw and using the plate as a template guide, cut the tank wall. It may take a few blades since material is SS. It would be safe to perform and NOT damage the tank.
remove the template plate and install 6" fitting. Most steel supplies places have 8" square plate, precut.

Great idea!!
Except when you bend that plate around the tank, the hole becomes oval. And the mill part.....that depends on how well equipped he is.

[Almond farmer]

Is the tank cylindrical with semi elliptical or hemi spherical heads?
What is the tank diameter.
If cylindrical the plate can be bent using two square bars on the edges. Get a steel pipe and weld a smaller tube or pipe say 3/4" long where the rod from the bottle jack press fits into the tube socket. Place the tube in the center of the edge supported plate and use the bottle jack pressure to obtain the desired radius to match the tank diameter.

on the distortion thing., simple geometry layout of an ellipse, have to do some geometry calculations to get the correct major and minor diameters.
Then, inscribe a circle within the ellipse equal to the minor diameter.
The hole could also be cut on a small lathe using a face plate, i.e. Atlas 6" swing.

The jig saw guide plate could be placed on the plate, tack welded to the SS tank, then run the saw blade along the edge of the tacked on plate.

[ryanjones2150]

Holy smokes, it's not a space shuttle, it's a container for brewing beer. The ancient summarians brewed beer surely without sanitary stainless anything, it's nothing like a Michael Angelo or building a piano. Plasma cut the hole, clean it up and weld that mammer jammer. The longer you over think it, the less time you have to enjoy the bubbles of your labor.