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TRX
02-05-2012, 12:56 PM
I have several pieces of low-carbon (1044 alloy) steel. I need to cut some slots in them, 9/16" wide by 1-1/4" deep, 6" long from side to side. I will be using an old Gorton 8-1/2D vertical mill. approximately Bridgeport size. I plan to use a 1/2" 2-flute end mill.

The mill originally had a flood coolant system, but it's gone now. I've been using oil and a brush or a spray bottle. Since I'd like a nice finish on these parts, I think I might need something better. It's time to add a coolant system anyway. I got a sheet of 1/8" Lexan to make some guards, and now I'm wondering what type of system is most appropriate for this particular job.

Since all the drains are already there, I can add a flood system. However, since this is a fairly deep slot I've been wondering about re-cutting chips. Is this likely to be a problem? Would a mister and compressed air to clear the chips be more appropriate?

DFMiller
02-05-2012, 02:05 PM
Best results will occurr if you get rid of the chips. If you are doing this manually just get rid of chips every pass. I have a mist free system that uses lots of air and a few drops of coolant to get rid of the chips. A wet dry vac can help.

I expect the experts will give you better tips.
Dave

lakeside53
02-05-2012, 09:30 PM
If you don't have coolent, blast the slot/cutter with air to remove the chips.

TRX
02-07-2012, 08:21 AM
I think I'll try flooding with cutting oil. I have a 5GPM gear pump and a 5-gallon bucket on hand. As soon as the electric motor gets here I'll build a bracket and driveshaft.

The pump has a screened pickup to keep the big swarf out. Is there any benefit to filtering the smaller particles out? I can add an automotive 1-quart spin-on filter into the pressure line easily enough.

lakeside53
02-07-2012, 12:17 PM
The auto type filter may stop any decent flow - your pump may not be able to develop the pressure required. Area is key... add some some panty hose spread wide with the pump inside.

If you're worried, put a magnet near the pump intake.

Impeller pumps (shaft drive, not "magnetically coupled" as with aquarium pumps) as found on on 7x12 bandsaws or many lathes work well for this type of thing - they can pass grit - gear pumps tend to wear out (eventually). I recently replaced a gear pump on a big Amana bandsaw that had many layers of large area filters and traps. Used a HF immersion pump - about $15... Supposed to be temporary 6 months ago... magnetic coupling is a pain, but the owner would rather clean it out than replace what's working.

Going to be messy on and around a BP!

TRX
02-07-2012, 02:50 PM
I don't think I'll have any trouble forcing oil through the filter. The pump is a small block Chevy oil pump. They're simple gear pumps. I have a 1/4hp motor that should drive it OK. A battery drill or speed wrench will make enough pressure to squirt oil across the garage if you forget to put the oil pressure sender in, so I should have plenty of power.

I was sort of hoping someone would recommend a water-base coolant and lots of air to clear the chips, but I guess I'll do it the old-fashioned way. At least I know that'll work. "There's no kill like an overkill."

For regulation, I'll splice a tee and a ball valve into the pressure hose, to divert unwanted oil back to the bucket.

I bought a 20' stick of 3/4x1/8" angle iron to frame the flood box with, and I have some metal shelving I can cut and bend to make a base tray. I should have enough scrap Lexan to make the box.

I know some oil will still get out, but no sense in making any more mess than I have to.

DFMiller
02-07-2012, 02:57 PM
TRX
I did say that already
"I have a mist free system that uses lots of air and a few drops of coolant to get rid of the chips."

Dave

bborr01
02-07-2012, 03:18 PM
I think I'll try flooding with cutting oil. I have a 5GPM gear pump and a 5-gallon bucket on hand. As soon as the electric motor gets here I'll build a bracket and driveshaft.

The pump has a screened pickup to keep the big swarf out. Is there any benefit to filtering the smaller particles out? I can add an automotive 1-quart spin-on filter into the pressure line easily enough.

No to the flood cutting oil. It will be toooo thick and gummy and create a bad mess, not to mention smoke that will blind you.

Use a water based coolant. I did jobs like that regularly when I was working and used a spraymist to keep things cool and an air blowgun to clear out chips when they started piling up. I don't like using a spraymist in a small area like my shop so I instead use a small squeeze bottle with a pin hole in the top. Squeeze a little coolant on things to keep things cool and lubricated, then a blowgun to remove excess chips as needed. I have seen guys in job shops use a 12oz coke bottle with a pinhole drilled in the cap. You don't need to stop cutting to clear the chips. Just alternate between the coolant and the air.

As to flood coolant, you need enough pressure on the flood to remove the chips from the slot that you are cutting. CNC machining centers are a good example of that. Most of them have several nozzles coming at the cutter from various directions to clear chips away. Just dribbling flood coolant will probably not be enough to clear the chips away.

Hope this helps.

Brian

bobw53
02-07-2012, 03:36 PM
I think the oil is overkill. A low carbon steel cuts perfectly fine and dandy dry, so you aren't really worried about that. CHIPS, that's going to be your problem.

I'm not totally clear on if your slot goes out the edge of the part, if it does, you've got it made. Just a light air blast or a mist if you must from the uncut to the cut side, chips will blow right out easy.

Closed slot, you'll just need more air pressure.

Likewise with coolant.

For cheap water soluble, head on down to any oil supply company and pick up a bucket of generic soluble oil.

Be aware that it is very easy to blow your chips back into the cutter with an air blast. Lighter thinner chips will move easier with air and with coolant, if you hit it just right, sometimes they will actually float out for you.

Ryobiguy
02-07-2012, 03:47 PM
I have several pieces of low-carbon (1044 alloy) steel.

Not to be a nit-picker, but isn't 1044 medium-carbon steel?

TRX
02-08-2012, 05:03 PM
I dunno; my reference material only has "high" and "low" to pick from.

beanbag
02-09-2012, 06:19 AM
If you run a coated carbide cutter, you can do it with air blast only. If you keep a consistent feed, the chips will just shoot right out.

If you want to run coolant, you have to use the right level, based on your experience. Either use very little in combination with air so that they chips can still blow out, or use a lot and have the chips wash out. The worst is to use an intermediate amount such that the chips stick around and clog everything up.

Because chip clearing in a slot is poor, it is extra important to run a consistent feed to get consistent chips.

derekm
02-09-2012, 03:29 PM
find a friend with a horizontal mill :)
it will be much easier