End mills to start with?

[ACHiPo]

I would actually recommend getting import mills. You will break some, especially the smaller sizes. Better to have that happen with cheapos than Niagras. Now, that being said, the problem with working with cheap mills is it will be hard to know what is your fault and what is because the mill is junk. Just assume it's your fault--when feel comfortable moving to good mills you will be very pleasantly suprised.

 

[WCraig]

Niagara 20080 1/4” HSS USA E7 Microshield/GP

Newbie here--that 1/4" Niagara, is it intended for chamfering edges?

Craig

 

[WCraig]

It’s a 1hp RF-30 clone, 2100 max rpm.

I've found the online tool from Little Machine Shop useful regarding MAXIMUM speeds and feeds:

Speeds & Feeds

The premier source of tooling, parts, and accessories for bench top machinists.

littlemachineshop.com

For example, the 3/4" HSS cutter in low-carbon steel has a recommended maximum of 460 rpm. OTOH, the recommended max for a 1/4" HSS in aluminum is about 3,000 rpm. I'm pretty sure you'll be fine at 2,100, however.

I'm not clear, however, about carbide cutters. As hobby shop guys, are we giving up anything significant by running them far below the maximum possible rpms? Eg, a 1/4" carbide end mill has a recommended max of 13,750 rpm cutting aluminum!

Craig

 

[DavidR8]

Newbie here--that 1/4" Niagara, is it intended for chamfering edges?

Craig

That’s a good question, I have no idea what it’s for....


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[DavidR8]

I've found the online tool from Little Machine Shop useful regarding MAXIMUM speeds and feeds:

Speeds & Feeds

The premier source of tooling, parts, and accessories for bench top machinists.

littlemachineshop.com

For example, the 3/4" HSS cutter in low-carbon steel has a recommended maximum of 460 rpm. OTOH, the recommended max for a 1/4" HSS in aluminum is about 3,000 rpm. I'm pretty sure you'll be fine at 2,100, however.

I'm not clear, however, about carbide cutters. As hobby shop guys, are we giving up anything significant by running them far below the maximum possible rpms? Eg, a 1/4" carbide end mill has a recommended max of 13,750 rpm cutting aluminum!

Craig

Another great question. I know that insert tooling on low rpm lathes is not great because most carbide inserts need high rpms, feed rates or depth of cuts.
No idea on a mill but I suspect that it’s not the same situation.


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[MrCrankyface]

I'd say the insert tooling part depends highly on what inserts you're trying to run.
I find that some of the sharper inserts will work great on low rpm lathe/mill but others won't.
I also find that they stay 'sharp enough' longer than my HSS tools, especially when pushing them a bit harder.
I found that CNMG/WNMG/APMT inserts were incredibly difficult to get to cut right whilst CCMT and DCMT will cut like a dream.

Might be a different story for carbide endmills.

 

[BrentH]

Hi David,

Get or make yourself a fly cutter for surfacing material. They will work well on most materials and you can resharpen them as the will take some form of High Speed Steel blank - same as your lathe. You can get a set of three pretty cheap on e-bay or Amazon.

For stock removal The roughing end mills are great and take a bit less Hp to cut through (your second example in the pic)

For finish the 4 or 6 flute but 4 should be enough

Typically 2 flute for Aluminium and 4 flute for steel and other metals - aluminium tends to stick to the cutter which can cause issues if you are going too fast.

Sadly the end mills do dull - small ones are not worth taking to sharpen - anything 3/4 and up is though (if they are good quality) - then you will start looking for a sharpener or surface grinder.......oh my

I shop Kijiji (Craigs list) for the guys selling off a bunch and then go for it and have fun. I have burnt out the small ones and chocked up the larger ones and broken a couple by taking just a bit too much....all about the fun!

The indexable ones will still leave a nice surface - don't be afraid to get a couple - some of the profile ones like 90 60 or 45 degree angle. You can still run up a good speed on your mill to yield a nice finish....

Then you will be looking for a slitting saw........

The fun is just starting!

 

[GunsOfNavarone]

@BrentH any reason you recommend a fly cutter over say a boring head? I was on the fence and I went Boring head just because of the ability to drastically control the size of orbit. I think I've seen them used on a lathe too, if memory serve me.

 

[BrentH]

The "Fly cutter" will allow you to square up stock and make things flat. The fly cutter runs with just one "tooth" on the work and takes the least horse power to run (just the one cutter removing material not 2, 3 4 etc). You can achieve some great finishes. The Fly cutter also can utilize high speed steel cutters (easier to sharpen). They are inexpensive compared to indexable cutter heads and for the hobby guys - they typically use the same tool steel as your lathe.

So you have a boring head - cool!!! - you can make custom sized holes and also face things if your set up right - may be a bit flexible over larger diameters if you are trying to face off a piece. etc - check out the ebay/amazon etc and pick up a set of fly cutters - you can then surface finish/square up and then bore away!

My mill came with an indexable cutter head (5 carbide inserts) that was good for 1-1/2". I have a 2 Hp Bridgeport with a QC30 collet. runs pretty decent and I also have a 3" indexable cutter. At work we have a small mill - could not do much without stalling - got a fly cutter set up (R8) and it was cleaning up aluminium to at least 0.030" depth of cut with no issue.

They are great for cleaning up crappy hard steel too as you can resharpen during the process as need be and you don't feel buggered if you hit a hard spot and chip the cutter - resharpen and repeat

Once you can get the project cleaned up and ready to make into a part ..... so many cutters and so little time ....LOL

 

[DavidR8]

I may attempt to make a fly cutter/facemill similar to the one made by @homebrewed.

Small face mill using tangential cutter

I recently made a small face mill that uses a 3/16" diameter HSS rod for the cutter. The idea was to replace an indexable face mill with something that would handle interrupted cuts better (I always seem to chip the inserts). I like the concept of the tangential cutter because they're dead...

www.hobby-machinist.com