What's new
What's new

End mill as a slitting saw, practical smallest diameter

Bill D

Diamond
Joined
Apr 1, 2004
Location
Modesto, CA USA
I was wondering, since I do not have a horizontal mill or a right angle attachment, What is a practical diameter endmill to use to cut 1/2 steel plate in a bridgeport type vertical mill. I figure it will have to do it in several deeper passes. 1/2" seems wasteful. Would 1/4" be prone to packing with no flood coolant or air blast. Just a manual mill with brushed on cutting oil.
In theory a 1/16 endmill would be more efficient but I am sure it would also be easy to snap off if anything goes wrong.
I do not think a smaller diameter would cut any faster anyway. Is there a rule of thumb like the diameter should be about the same as the final cutting depth?
Old school manual mill. No high speed spindle, flood coolant, air blast or power feed. Do not care about max speed just want a reasonable rate of cut with no chip packing problems.
Bill D.
 
Bandsaws are more efficient if available. I have even read about hand-held circular saws that can cut steel plate if the cut is straight.

Larry
 
Milwaukee do a really nice metal cutting circular saw, I think evolution and Makita too, great up to 1/2” ear muffs and visor, apron too, they spew tiny hot chips if your not careful they get you, good thing is shoving bevels on is easier than grinding, ( there’s even a roller version for pipe but I can’t remember the make), plus plasma cutting is definitely something to think on, edge not to bad, however they are more stock cutting than slitting, none are precise in fact nothing can really duplicate a horizontal with a slitting saw, well ok there’s edm and water jet but if your pockets were that big you wouldn’t be asking, I have a small horizontal mill, only a 2’ table I got for cheap, it’s ancient but still delivers a good cut with care ( though the leadscrew nut could use replacing, it’s on the list).
1/8” is the smallest endmill I’d try, to me that’s scary small especially long ones patience required with them, start with a short one move to next size and so on, turn the work over and go from the other, if possible
Mark
 
I would grab whatever was closest to me if I were on a manual. Otherwise 1/4 or 5/16 if I had go looking. We use 1/4 on the cnc for cutting out shapes in plates. I don’t think I would go less than 1/4.
 
I think a saber saw with a metal cutting blade would be faster and have less breakage than a 1/8" end mill. Or even than a 3/16" one. Perhaps somewhere around 1/4" or 3/8" diameter end mills you may break even between the two tools.

I have cut thinner steel plate with my saber saw. It isn't super fast, but it does work and quite safe if the blade does break as it will be under the steel you are cutting. Do use some cutting oil with this and a blade with the correct number of teeth for your thickness (6-10 TPI).

Another thought would be a track saw with a metal cutting, carbide tooth blade. You could make several passes, gradually increasing the depth on each one. The track will allow the blade to follow the same path for each pass. I am not so sure about the use of a cutting oil or coolant here due to the carbide. But PLEASE DO USE PROPER SAFETY GEAR FOR THIS. GOGGLES FOR SURE! Perhaps a shop apron and something I don't often recommend in the machine shop, gloves to protect your hands. And clear any flammables from the path of the sparks - THERE WILL BE SPARKS!
 
I know a lot of people like to "do it themselves" but sometimes your best option is to buy a piece of
material cut to size and avoid all the headaches. If you really need to do it yourself I would be
prepared to sacrifice some material and use a 3/8" or 1/2" roughing endmill. Something in those
sizes would walk through 1/2" plate pretty quickly and save you a LOT of aggravation...
 
Circular saw suggested above got me thinking... Bridgeport mills have that attachment point on the back for the shaper accessory. What if one mounted the circular saw in there, then the table can be used for cutting plate as one would do with an angle attachment and a slitting saw in vertical orientation. Might be a bit scary though :D
 
Thanks for the feedback. I had thought 3/8 would be pushing it. Sounds like I was correct. I will look into that metal cutting blade at Home Depot. Clamp on some angle iron as a guide and go to town. If I was really brave and stupid I could use it in a mill as a slitting saw.
Bill D
 
sounds like you want to do it cheap........... best bet, call around to local shops, one of them have a bandsaw or plasma cutter that would take 5 minutes to cut 1/2" thick. bandsaws have about the same material loss as a plasma give or take 0.030" kerf.

hell your local steel supplier should do it for you also.
 
Hi All:
For those of you who posted about a 1/8 endmill being super small for use on a Bridgeport...I have some news for you.
For what the OP is trying to do (through slotting) you can do a really good job of it if you plunge rough and make sure you use a stub flute cutter with a relieved shank.
I'd run it balls out for spindle speed and run a stepover of maybe 0.007" or so, and just peck it with the quill.
1/8 diameter 4 flute carbide is pretty strong against end load...once you get the hang of it I doubt you'll have any trouble.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 
Hi Thermite:
You wrote "That doesn't make it a good idea, NOW."

I'm having a hard time understanding the point you wish to make.
Are you saying plunge roughing on a manual mill is an obsolete technology?

Should I have advocated for the OP to just toss it up on the wire EDM? or maybe the laser, or the waterjet?

I'm baffled...enlighten me please.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 
OK, NOW I get it:
I was stuck on the notion that the OP wanted to slot something to make a pinch clamp or similar and wanted to do it on the manual mill with a little cutter.
It never occurred to me that he might want to use it as a cutoff saw to chop up a bar.
You are correct, of course, and re-reading the OP's post, I cannot see where i got my original notion.

Musta pulled it out of thin air!:crazy:
Gettin' old really sucks...you start imagining things!

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 
Nowt to do with the value of a vertical mill .... as a vertical mill.

Makes a poor excuse for an ignorant saw is all. Squaring-up material by milling - if/as/when need-be, is a whole different tasking. Also subject to better methods.

Would one mill steaks off a beef carcass, bread off a loaf, or bacon off a pig's belly - just because they had a BirdPort mill?

On second thought.. don't answer that.

Time for Forrest to jump in with thoughts on lard and olive oil as cutting lubes.
Bill D
 
I like Marcus' plunge cutting suggestion.

Sure a shop with the correct saw could do it in much quicker and more accurately, But is the time it would take to load it on a vehicle, drive to that shop, wait around for the cut, drive back and unload less than it would take in house? Seems unlikely for one or a few parts, and the $$ saved would pay for one (or several) carbide endmills.
 
Chain drill it then use an end mill to neatly connect all the holes. That way you won't get the swarf buildup that breaks small end mills.
 








 
Back
Top