Best way to get a perfect 3-7/8" hole in 16 ga steel?

Post by **Redneck7** » Fri Nov 06, 2009 12:16 pm

My roommate can take it up to the metal shop in the Architecture school, I can order a hole saw, worst case I'll get someone with a steadier hand than I to use a jig saw etc...just curious what the best tool for the job is here. Need 2 holes around 3-7/8", maybe 3-15/16" and really didn't want to buy a $25 hole saw for two of them, especially if there was a better way.

Thanks
Ryan

Post by **willhf1011** » Fri Nov 06, 2009 12:33 pm

how close do they need to be to size? plasma/ torch/ saw and then grind would be pretty precise

Post by **Redneck7** » Fri Nov 06, 2009 2:09 pm

willhf1011 wrote:how close do they need to be to size? plasma/ torch/ saw and then grind would be pretty precise

Press fitting gauges into the holes is the goal...

Post by **willhf1011** » Fri Nov 06, 2009 9:25 pm

If you have access to a die grinder and don't want to buy a hole saw then i'd say cut them out rough and then open the up with the die

Post by **jonesy** » Sun Nov 08, 2009 12:27 pm

hole saw / drill bit will always be about .015 too big ..... FYI. so press fit wont happen.

the only way to get a press fit for those guages (assuming you mean a true press fit / interference fit) will be to undersize the hole and finish it out to size by hand ....

or find a machine shop with a CNC to mill it out ... which will be your best bet.

but since you say gauges ... im assuming you dont mean a true press fit ... and im assuming that you have probably 1/8" to 3/16" to play with because of the bezel on the face of the gauge .... holesaw or undersize it / rough cut it and then open it up with a burr on a dremel / die grinder

thank me later.

Post by **MILLER** » Sun Nov 22, 2009 12:32 am

You dont have to have a CNC. You can use an adjustable boring head on a regular mill. Maybe the metal shop might have one, or something similar.

Post by **jonesy** » Fri Nov 27, 2009 3:33 pm

MILLER wrote:You dont have to have a CNC. You can use an adjustable boring head on a regular mill. Maybe the metal shop might have one, or something similar.

yeah ... boring bar on a mill will definitely do it ... but clamping that dash piece will be interesting unless you back it with a block that you dont mind milling through. a regular vice will run the possibility of bending or distorting the piece.

Post by **MILLER** » Mon Nov 30, 2009 7:01 pm

That's what the sledge is for.

Post by **Redneck7** » Mon Nov 30, 2009 9:22 pm

You guys somewhat lost me. My experience in machine shops is limited to "Richardson, go drop [part X] off at the machine shop" followed by "Richardson, go pick up that part..."

Really only get the before and after (and the invoice).

My priorities have slowly been shifting over the past few weeks to primarily worrying about moving out and making sure I graduate, so I haven't really given it much more thought, will probably ask my roommate to take it up to the metal shop and just ask for the 2 holes I've drawn on the metal to be cut, however they want to cut them.