Posted By: GKMOPAR
Sheet metal cutting - 01/18/14 04:33 PM
What is the best way to cut the two 4" scoop holes in a Demon hood? Too big for a hole saw and I'm affraid a jigsaw will be a rough cut even with a fine blade.
Sheet metal cutting
Posted By: mattsmopars
Re: Sheet metal cutting - 01/18/14 04:59 PM
I cut holes under the twin scoops on my duster. I was able to find and use a 4" hole saw from potters. Then cleaned up the edges with a carbide bit. Then used the factory rubbers.
Matt
Matt
Posted By: RapidRobert
Re: Sheet metal cutting - 01/18/14 05:02 PM
I used a sabersaw with a fine blade (as you described) to cut a circular piece of metal out of the side of a washing machine sitting in the back yard for an anticav plate. The cut was nice & smooth & I dont have much metal working experience. I was surprised that it came out that nice. Go slow & keep your eye on the blade, keeping it on your circle
Posted By: flypaper
Re: Sheet metal cutting - 01/18/14 06:01 PM
a electric or pneumatic 4 inch cut off tool 
Posted By: DAYCLONA
Re: Sheet metal cutting - 01/18/14 08:07 PM
Quote:
What is the best way to cut the two 4" scoop holes in a Demon hood? Too big for a hole saw and I'm affraid a jigsaw will be a rough cut even with a fine blade.
Well you can hack your way through the hood with hole saws, jig saws, etc, or you can do it professionally, find someone that does Industrial Electrical work to borrow a Greenlee set, or perhaps there's an Agricultural/Industrial tool rental store in your neck of the woods, use a Greenlee hyd. punch/knock out set, simple to use, drill a 3/4 to 7/8" dia hole in the center of the hole you want to open up, install the dies upper half on top, thread the lower die on the shaft untill it hits the underside of the hood and all the slack is taken up from the die, then just pump the handle of the jack, and presto, nice clean hole, no burrs, no chipped paint, no metal distortion, nothing, just a clean hole...practice the set up on a piece of scrap metal until you learn how to assemble the die, and any spacers required, because you want to do it once, and do it right
FYI, you want an Industrial Grennlee set up, as they range up to 6" hole dia.'s
Posted By: DAYCLONA
Re: Sheet metal cutting - 01/18/14 08:16 PM
Here's a small Greenlee...
Posted By: DAYCLONA
Re: Sheet metal cutting - 01/18/14 08:26 PM
I use a Greenlee punch to knock the holes out in the top's of Charger fenders for under the fender scoops...no distortion, no mess, it takes longer to drill the 7/8" dia hole required for the arbor than it does to punch a hole...every car builder should have a set 
mike
mike
Posted By: GKMOPAR
Re: Sheet metal cutting - 01/18/14 08:27 PM
Thats pretty slick..
Posted By: DAYCLONA
Re: Sheet metal cutting - 01/18/14 08:40 PM
Quote:
Thats pretty slick..
Gerry, if you decide to use a Greenlee punch set, I'd use a Uni-bit to drill the required hole for the arbor...and you could also generate a hole using a small "hand" Greenlee, that requires a 3/8" dia starting hole, then you use the "hand" Greenlee to open up a hole for the arbor shaft on the hyd unit
FYI...Greenlee's are also available to make square and rectangular and oval holes in sheetmetal
Posted By: dirt
Re: Sheet metal cutting - 01/18/14 09:52 PM
you could try it with offset aviation snips. I have cut 8' lengths of 18 GA steel with them and you can also cut fairly tight curves . you would just need to cut a hole to get them started .
midwest aviation offset snips
midwest aviation offset snips
Posted By: Stanton
Re: Sheet metal cutting - 01/18/14 10:31 PM
Hole saw ... run it backwards. Takes longer but it will do a nice job.
Posted By: cbusters
Re: Sheet metal cutting - 01/19/14 05:45 AM
Quote:
you could try it with offset aviation snips. I have cut 8' lengths of 18 GA steel with them and you can also cut fairly tight curves . you would just need to cut a hole to get them started .
midwest aviation offset snips
Snips will stretch the metal and a hole saw will heat and warp the metal. Use the knockout punches.
Posted By: Alaskan_TA
Re: Sheet metal cutting - 01/19/14 06:45 AM
Quote:
it takes longer to drill the 7/8" dia hole required for the arbor than it does to punch a hole
Start small. Drill a small hole for a 7/8" punch, then move up to the big punch with the larger arbor.
Posted By: elitecustombody
Re: Sheet metal cutting - 01/20/14 12:52 AM
Drill, air body saw,die grinder with carbide bit for clean up or Greenlee kit
Posted By: astrobuf
Re: Sheet metal cutting - 01/20/14 04:24 AM
I've actually had very good luck trepanning sheet steel using a Malco circle cutter.
http://www.amazon.com/Malco-2-Inch-12-Inch-Cutter-Accessory/dp/B000289542
The Greenlee punches would be great, but very expensive.
I've used my Malco to cut up to 8 inch diameter circles using a hand drill. It worked surprisingly well.
Astrobuf
http://www.amazon.com/Malco-2-Inch-12-Inch-Cutter-Accessory/dp/B000289542
The Greenlee punches would be great, but very expensive.
I've used my Malco to cut up to 8 inch diameter circles using a hand drill. It worked surprisingly well.
Astrobuf
Posted By: GKMOPAR
Re: Sheet metal cutting - 01/20/14 05:07 AM
I do like the greenlee but it is a bit expensive for the limited times I may use it. The Malco cutter looks like a more affordable alternative.
Posted By: astrobuf
Re: Sheet metal cutting - 01/20/14 05:30 AM
Just practice a time or two before you do the real surgery. Go slow, have someone help you, say by spray oiling the cutter as you work your way around. Test the cut radius as I've noted the scale on the tool is off by a a bit (1/32 or so on 8 inches diameter in my case)
Astrobuf
Posted By: DAYCLONA
Re: Sheet metal cutting - 01/20/14 06:00 AM
Quote:
I do like the greenlee but it is a bit expensive for the limited times I may use it. The Malco cutter looks like a more affordable alternative.
Dude,...google is your friend, Sunbelt Equipment and Tool Rental in Hilliard Ohio, your home town, rents Greenlee equipment 5274 Cemetery Road Hilliard Ohio call them at 614 876 2605
Mike
Posted By: GKMOPAR
Re: Sheet metal cutting - 01/20/14 09:10 PM
I checked it out online with Sunbelt Saturday and did not see it listed. I called them today and they did not have one local but could get it. It would cost about $100 for them to ship it from another location and rent to me.
Posted By: DAYCLONA
Re: Sheet metal cutting - 01/20/14 11:49 PM
Quote:
I checked it out online with Sunbelt Saturday and did not see it listed. I called them today and they did not have one local but could get it. It would cost about $100 for them to ship it from another location and rent to me.
Gerry, sounds good! if you go this route, you'll need the 3 1/2" Greenlee punch as the actual hole size punched is 1/2" larger, I measured my set, the 3 1/2" punch will give you a hole dia of 4.020", just a whisker (5 human hairs actually) over 4" the Greenlee pn# for the 3 1/2" die pcs are:2982AV for the punch, and pn# 2981 for the die, make sure the set you rent has those, as Greenlee makes multiple set cases up to 6"
Mike