Help me find this end mill bit please

[BlackdogGS]

4 flute, 1/4” dia, 1” length of cut, 4” overall length

I’m coming up empty, where can I get these?

 

[GrantCee]

Here you go (wait for it to stop loading - it refreshes several times while it does the search):


https://www.mscdirect.com/browse/tn...0+4288247891+4288247527+4288247828+4288247914

 

[BlackdogGS]

Here you go (wait for it to stop loading - it refreshes several times while it does the search):


https://www.mscdirect.com/browse/tn...0+4288247891+4288247527+4288247828+4288247914

Thanks! I’m not a machinist and I’ve been using some apparently cheap mill ends as I seem to be going through them rapidly. I’m milling some 7075 aluminum and the cutting edges are chipping off. I’m using a router. Hopefully this one you linked will get me through the project.

 

[American Locomotive]

You should probably be looking at 2 or 3 flute end mills, not 4 flutes.

I'm not a machinist either, but I have worked for a large CNC machine shop. They typically used 2 or 3 flute high helix angle end mills for aluminum. Standard 4 flute end mills often have trouble evacuating chips, so the cutting edges end running over their own chips.

 

[DocsMachine]

If you're using a router, chances are you're turning it WAY too fast. A typical router turns at 20,000 RPM or so, while a typical manual milling machine might see 3,000 RPM.

No matter what you do, if you're overspeeding it by that much, you're gonna get chips and broken tools.

It's not impossible to do, of course, people do ti all the time. Just figure the endmills are consumable like a cut-off wheel, and you're gonna go through a couple of 'em per job.

Doc.

 

[txvwnut]

Slow that bit down your turning it too fast. Either get a mill or a router speed control, in my mill I run around 600 or so rpm when milling aluminum and I watch the bit for buildup of sticking aluminum.

 

[Provincial]

Without some kind of controlled feed rate (meaning moving the tool a specific distance for each revolution of the cutter) you will have problems with "crashing" the cutter. This is why milling machines have lead screws to feed the table.

You could feed a 4-flute cutter 40 inches per minute to take a 0.0005 cut per tooth, but you need to move the work precisely that amount, not average 40 inches/minute.

 

[Doug Arthurs]

Try a cheap router bit. Not sure what you are doing exactly but with some wd40 as cutting fluid you might bring your cost of milling down.

 

[Doug Arthurs]

I meant a carbide tipped one.

 

[bugnut]

American Locomotive has it correct. Speed is way high unless the depth of cut is really small. The deeper the cut, the more material per revolution, the harder to evacuate. Lube like kerosene, wd40 or the like, air blasting the chips out of the way, etc. Got to get the path cleaned and lubed.

 

[Cypherian]

https://www.onsrud.com/Products/40158.asp It can be done with the right bits check with these guys.

Cypher

 

[glend123]

Also, do you need it that long? If it's hanging out 3" thats not good for tool life either.
Get a 2 flute carbide tool, chuck it up so the bare minimum is sticking out. Get you feed rate and rpm right, and lube it with wd-40 or kerosene or odorless paint thinner, otherwise the aluminum will stick to the cutting edge and build up.

 

[HenryAZ]

I like Maritool for machining bits and other accessories. Personalized, fast service.

 

[Barrymaxx]

Probably a 80% er.

You need to take your time. We did 3 of them with the same endmill. I probably took an hour to do each. Its tedious but the result is fantastic.

 

[BlackdogGS]

80% ar receiver?

 

[BlackdogGS]

Can the chipped end mills be ground to renew? It's just the tip that's chipped and it looks like I could grind the tip off to be usable again.

 

[txvwnut]

If it’s the end they can be ground but you need a fixture to hold the end mill at the proper angle for grinding.

 

[American Locomotive]

Yeah, the fixtures to regrind them are tricky, as there are a lot of different angles you need to account for.

But like I mentioned earlier, a 4-flute end mill is not the right tool for what you're trying to do.

 

[BlackdogGS]

I was thinking about just grinding 1/4” on the end square. No?

 

[Provincial]

I was thinking about just grinding 1/4” on the end square. No?

If the end of the cutter will not be engaging the work, yes that would work as long as you are working from a free edge. It will not cut on the end.

If you grind it, go slow and use coolant or water to keep it from heating up and losing temper.