Power Route cutting steel

[oldtech]

Just a note. I have cut my first mild steel on my PR using High Speed Machining. For the test I cut out a 10x10mm square out of 16 gauge mild steel. I did not use any cooling, but I did use compressed air to help move the chips.

I used the following speed and feeds as determined by GWizard for 1045 steel (from Home Depot - the type of alloy is not specified).

Speed Tiger 1/16" end mill on 1/8" shank

RPM: ~14000

Surface speed: 76 m/min

Cut depth: 0.6 mm

Cut width: 1.5875 mm

Feed rate: 146 mm/min

Plunge rate: 60 mm/min

Deflection 0.0034 mm

I measured the square after cutting and got 10.01 x 10.01 mm using Mitutoyo digital calipers. The finished cuts were clean and smooth.

According to GWizard, I should be able to cut brass, tool steel, high carbon, stainless, cast iron, and titanium using this machine with a 1/16" bit.

[oldtech]

I've also been successful in cutting an M3 nut using the same material, feed, and speeds. For cutting the threads I used a manual M3 tap. It's just a 6mm diameter hexagon with a 2.5mm hole for the threads.

[kevin]

That's pretty cool. Are you planning a project using steel or just testing the machine's capabilities?

[oldtech]

Since the tests have been successful I'm preparing, as we speak, to cut out a mounting panel for my linuxcnc mesa 2i25-7i76 controller box for my Power Route 4th axis mod. It's a long story which I will post details on in the future. Right now I did not want to mount electrical components that could get hot on a wooden base. So I needed a metal base for mounting.

I could have used aluminum, but I read in cnccookbook about using High-Speed Machining for harder materials and decided to give it a try.

www.cnccookbook.com/high-speed-machining-trochoidal-milling-hsm-speeds-and-feeds/

The secret is to use smaller bits with feed and speeds in the range of the Power Route. This keeps the torque and resulting deflection within manageable limits.

The main limitations of smaller bits are:

1) More time to remove larger amounts of material
2) Less stick out which means that the ability to machine deep pockets will be limited

In the future, I will try even harder materials and will consider using those materials in future projects.

[kevin]

Sounds like an interesting project. Hope you post pics.

[oldtech]

BTW I'm also impressed by Sherline mini machines. The basic idea is to again is to match the tools and techniques to the machine that you have. Their demo of cutting steel threads using a hand-operated lathe is impressive. You don't need big powerful machines unless you need to produce commercial quantities at high speed.

I still remember seeing my Dad's shop when I was still in grade school. The lathe he worked on was driven by a complex ceiling-mounted belt-pulley system driven in turn by a big engine (only one engine for the entire shop of dozens of machines). Nothing moved very fast and the machines were big but not complex, yet he was able to machine parts to 1/10000 of an inch. This was long before cnc or metric anything and would be viewed as dangerous and very primitive today. If you were not careful you could get caught in those moving belts especially when changing speeds. You did not have the option of turning off the engine - you had to do it on the fly. The belts were leather and 4-5 inches wide.

[oldtech]

Today I cut out 4 custom power supply mounts using the same material, feed, and speeds. I did discover that end mills need to have a byte into the material. For this mild steel using a slow ramp spiraling down caused a significant burr to form along the cut. So I dropped the ramp and that fixed it.

After the cut, I then bent the mounts along each of the score lines.

[oldtech]

I cut out the electronics mounting plate from 16 gauge mild steel today. I did have to make two attempts because the material slipped during cutting on the first attempt. The second attempt went smoothly.

The plate is 280mm x 380mm and 1.5mm thick (11 inches by 15 inches). As a part of the cutout, I drilled 2.5mm holes for mounting the components. These will be tapped manually for M3 screws so that components can be mounted from the top.

[Bruce]

Jun 17, 2020 3:08:55 GMT oldtech said:

BTW I'm also impressed by Sherline mini machines. The basic idea is to again is to match the tools and techniques to the machine that you have. Their demo of cutting steel threads using a hand-operated lathe is impressive. You don't need big powerful machines unless you need to produce commercial quantities at high speed.

I still remember seeing my Dad's shop when I was still in grade school. The lathe he worked on was driven by a complex ceiling-mounted belt-pulley system driven in turn by a big engine (only one engine for the entire shop of dozens of machines). Nothing moved very fast and the machines were big but not complex, yet he was able to machine parts to 1/10000 of an inch. This was long before cnc or metric anything and would be viewed as dangerous and very primitive today. If you were not careful you could get caught in those moving belts especially when changing speeds. You did not have the option of turning off the engine - you had to do it on the fly. The belts were leather and 4-5 inches wide.

That sounds like the old craftsman trades at Silver Dollar City in southern Missouri.  I can watch those guys work for hours.   

[oldtech]

The shop I described was in Pitcher, OK (now a toxic superfund site razed to the ground). My Dad also got to work on some of first cnc machines in the '50s and '60s.