Cutting a 4" disk out of 1" steel plate

I have a piece of CRS, about a foot square and 1" thick. I want to cut out 2 disks about 4" in diameter. I will ultimately turn and
finish them into flywheels.
Given my tools, here are my options:
1. Rough out the disk with the gas axe, grind away kerf with angle grinder, turn on lathe.
2. Mount plate on rotary table, taking small passes mill out disk, finish on lathe.
3. Try to cut out disk with sabre saw, finish on lathe. Painful just thinking about it...
Any other options or suggestions?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

1) Call up metalmart and order two pieces of 4 inch round stock one inch long. It might cost you 20 bucks but look at the pain you are saving. I would also advise playing with the stock dimesions before ordering. I just ordered some bar stock and it didn't cost much more for 3 feet than 1 foot.
2) Find someone with a heavy duty bandsaw.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jim,
Just use the best tool available, and consider the value of your time.
Myself I would bandsaw the disks on my vertical bandsaw. Your method of "gas axe and grind" sounds doable if you can burn reasonably well.
As you say, sabre saw sounds painful.
Can you fit your gas axe to a crude circle cutting attachment jury-rigged?
One other method would be to phone metal fabricators in your area and check their price for disk burning from your material.
Also a scrap yard may have disks from boiler manufacturer's scrap pile.
As a final resort you could cut out the disks by drilling.........I used to do this before I got my band saw and modified it for metal cutting. I used 3/16 dia. drills because I had a lot of them.
Trust this is of some help.
Wolfgang
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Lacking a torch myself and often times needing roundstock and only having flat stock to make round out of, I resort to my rotary table and make em.May be a bit time consuming in some cases. I have made a heap of round items and disks form plate stock, and ifnish turn it on a lathe.Works fine....Fire axe may be quicker, but like I said I do not own one and I hate doing interuped cuts etc if I can help it.
I do have a metal cutting bandsaw which is what I rough out plate stock on now, which certainly would be better than using a sabre saw IMHO.
Doing it on a RT is not a bad job in all reality though.
wrote:

--
\|///
( @ @ )
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
use a cutting guide with your torch. best guide is one cut from 20 ga steel, supported about 3/8" off the surface. A piece of 1/2" plywood will do. Guide diameter is your rough out diameter minus the diameter of the torch head. Clean up the worst of it with the grinder, chuck it in the lathe. the first few passes aren't fun but it cleans up quickly.
I made a face plate and a chuck backing plate for my lathe out of 1" stock this way. Takes more time to talk about it than just do it.
Jim Stewart wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I've had good luck drilling a series of holes and then going to the cold chisel. John

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jim Stewart wrote:

Forget the saber saw. If it were me I'd certainly flame cut the plate.
This would be a good application for one of those Val-cut trepanning tools, just bolt the plate to your mill table and trepan your 4" disks. If you really knew what you were doing you could maybe grind a trepanning bit you could use in a boring head.
GWE
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Hole saw in a drill press, with a new saw it should take about 15 minutes per disk. Been there done it.
Best Regards Tom.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Flood with coolant all the while.
Joe Gwinn
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

And drill a chip clearance hole (or several) Geoff
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
azotic wrote:

Second this method
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
azotic wrote:

I like the general idea, however I'm not sure just any drill press is up to it. A friend and I did a 3 inch hole in 1" CRS this way in a little rockwell knee mill, and found that even on the lowest speed it was near stalling out - for 4 inches (or a bit over for finishing allowance) I'd probably want a bridgeport with back gears. Or maybe figure out some way to fixture the workpiece on the lathe carriage and use the lathe to spin the hole saw.
We drilled some 1/2" holes around the circumference to help with coolant flow and chip clearance.
I think we also had to flip the workpiece over half way through - alignment was easy as there was a pilot hole (the slug was waste in our case, we wanted the piece it was cut from)
Also, I wouldn't try to hold a hole saw of that size in a drill chuck. In our case we were able to grab a larger diameter part of it with a collet, rather than the narrow part meant to be chucked.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Circles out of plate is something I've done occasionally. I use a shop made circle device on the head of the c-torch. It's a modified cable clamp and some stock and rod. Center drill, set the radius and go. If everything is adjusted perfect the results are sweet. Finish on the lathe with a stub arbor.
DE
-
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Find someone with a good PLASMA CUTTER.
It will change your life as you know it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Gas axe, but center pop the middle of the disk, and attach a trammel point to the torch, approx 2 1/8" from the edge of the center hole, at the right height to keep the flame the correct distance off the steel. You _will_ be amazed at how smooth you can cut, once you figure this out. Of course, right sized, CLEAN tip, with correct cutting pressures for the steel indicated are assumed. I can email a picture, if you don't know what I'm talking about.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jim, Easy; Call McMaster Carr today, open package tomorrow. Machine flywheels tomorrow night, move on to next part
Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I have read at least a dozen other posts on this subject. Last Thursday our blacksmith club had its monthly meeting at a steel supplier's shop in our area. Right by the saw were lots of rounds of differing sizes, up to at least 6 inches diameter. I'd go with cutting your parts out of round stock that way. There were several posts about using a hole saw. When sawing out 1 9/16" diameter holes in 1 inch plate, which I do now and then, it takes a fair amount of power and about 2 minutes per hole at (too fast at 350 rpm). A 4" hole means 12 1/2" of cutting contact or 4 times as much as in my case. That's a lot! I also did this hole cutting on a Bridgeport EZ Trak. I can take 1/4" deep cuts with a 1/2" corn cob end mill and it went pretty well.
Pete Stanaitis --------------------------- Jim Stewart wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.