[JWeb]

Hi all... I recently purchased a Micro-Mark 82573 Mini Mill and 82710 Mini Lathe. I am a professional engineer, though I am absolutely a beginner at machining. The current project I am working on entails machining aluminum blocks to make a fixture that will slide on 5/16" shafts in both the X and Y directions under the control of stepper motors.

I have set up the 82573 and everything works great. It is truly a great little tool. Among many other accessories, I purchased a fly cutter set from LittleMachineShop.com (set #3094). I am attempting to use the 1-3/4" fly cutter to mill the surface of a 3" wide x 1" thick 6061 aluminum block. The cut is intended to be 2-1/4" x 3", down to a depth of 3/4". A picture is attached of the initiation of this cut.

However, I'm not sure if I have the fly cutter set up properly. It is chattering terribly. As received, I don't believe the tool bit was oriented properly, so I flipped it over. I've tried slow tool speed, fast tool speed, deep cut, shallow cut, fast feed, slow feed, etc. Nothing seems to result in the "sweet spot" -- and certainly not like anything in the videos I've seen online of fly cutting on the 82573 where it looked like it was cutting through butter. Something doesn't seem right with my setup. The best I can do is about 0.001" passes at very high tool speeds and very slow feeds... at this rate, it will take me hours to get down to 3/4". I've also attached a picture of the fly cutter as it is installed in the collet right now (the white paper is there for contrast to aid in you seeing the tool bit).

Do I have this set up properly? Do I have the tool bit oriented in the fly cutter properly?

Can I expect to cut both to the right and to the left... that is, in both directions?

Am I really just cutting as fast as the 82573 will allow? (The chattering suggests to me that something else is wrong...)

Any other tips for a beginner? Though slow going, I'm having great fun learning.

Thanks in advance,

Jeff

[MrWild]

It's amazing you got it to cut at all. HS tooling is not plug and play. You need to grind that tool into a proper cutter. Right now it's in the raw state. You need to grind the rake, relief, and radius at the tip. It needs to look like a left hand lathe tool bit

[Mogal]

Looks like to need to grind your bit.

Fly cutting - Home Shop Machinist

[MrWild]

Looks like to need to grind your bit.

Fly cutting - Home Shop Machinist

They don't say in the first few pictures showing rake and relief, but the last picture shows a radius at the tip. This is important for smooth finish.

[mwood3]

buy these

http://www.harborfreight.com/1-4-qua...ack-40637.html

or these

http://www.harborfreight.com/10-piec...its-38886.html

and life is gravy

The AL bits can be used for normal "clockwise cutting" i suppose you could use the AR bits in reverse? anyone care to comment on this?

I use these and for the price you cant beat em...

P.S. if anyone knows where i can get 5/16" and 1/4" brazed carbide bits in packs that only come with AL let me know

EDIT: nevermind found some http://cgi.ebay.com/10-PCS-AL4-STEEL...efaultDomain_0

[MrWild]

buy these

http://www.harborfreight.com/1-4-qua...ack-40637.html

or these

http://www.harborfreight.com/10-piec...its-38886.html

and life is gravy

The AL bits can be used for normal "clockwise cutting" i suppose you could use the AR bits in reverse? anyone care to comment on this?

I use these and for the price you cant beat em...

P.S. if anyone knows where i can get 5/16" and 1/4" brazed carbide bits in packs that only come with AL let me know

EDIT: nevermind found some http://cgi.ebay.com/10-PCS-AL4-STEEL...efaultDomain_0

BUT those are RAW cutters that might work as is, just like the HS bits kind of work as is. I disagree on the cemented carbide blanks for aluminum for the main reason you can't sharpen them properly with a bench grinder, but you can sharpen HS bits with one. HS works just fine and dandy in aluminum and mild steels when sharpened properly.

If you don't want to learn how or be bothered with sharpening, get "indexable" carbide tooling. A 1" shell cutter is the maximum diameter that should be used with that mill. Used indexible carbide endmills are cheap on ebay. They cut like butter and leave nice finishes.

[mwood3]

BUT those are RAW cutters that might work as is, just like the HS bits kind of work as is. I disagree on the cemented carbide blanks for aluminum for the main reason you can't sharpen them properly with a bench grinder, but you can sharpen HS bits with one. HS works just fine and dandy in aluminum and mild steels when sharpened properly.

If you don't want to learn how or be bothered with sharpening, get "indexable" carbide tooling. A 1" shell cutter is the maximum diameter that should be used with that mill. Used indexible carbide endmills are cheap on ebay. They cut like butter and leave nice finishes.

we have used this same style brazed carbide tool at work, and right out of the box they cut wonderfully, we use them on anything from aluminum to Tool steel...the also last nearly forever...I was under the impression that the ones from HF were also pre finished...the have a very sharp edge and look right to me...I will try some test cuts this weekend and post results I think i have some A2 laying around...

also they can be sharpened on a bench grinder with the proper wheel(green wheel) and a steady hand/tool rest...

[JWeb]

It's amazing you got it to cut at all. HS tooling is not plug and play. You need to grind that tool into a proper cutter. Right now it's in the raw state. You need to grind the rake, relief, and radius at the tip. It needs to look like a left hand lathe tool bit

Well, that's embarrassing! I guess the only reason it cut was because it is aluminum vs. HSS. Thanks so much to all who posted tips and advice -- everything is very useful.

Do the indexable tools work almost as well as the real deal? Do you have to orient the cutter at an angle at the end of the shank in order to urge it to work well swinging in an arc (as opposed to in a straight line on a lathe)?

Off to grind some tools!

[WaveDude]

I see a belt drive in your future--or a bunch of broken gears. Be very cautious, lock the head, use sharp tools, and take light cuts. I have the same mill (and lathe too) and fly-cut with it when needed (can't beat it for smoothing out a big area) but only after going to a belt drive.

And if your planning on fly-cutting a 3/4" deep slot you'll be there for days. If you have a saw--hack out most of that first. Otherwise use and end-mill to get rid of most of that and then fly-cut it smooth if needed. You'll need a properly shaped bit to get your fly-cutter up to a shoulder.

[MrWild]

we have used this same style brazed carbide tool at work, and right out of the box they cut wonderfully, we use them on anything from aluminum to Tool steel...the also last nearly forever...I was under the impression that the ones from HF were also pre finished...the have a very sharp edge and look right to me...I will try some test cuts this weekend and post results I think i have some A2 laying around...

also they can be sharpened on a bench grinder with the proper wheel(green wheel) and a steady hand/tool rest...

Holy cow. Who is the Lead man in your shop? I honestly don't want to sound disparaging. NO, you do NOT use them right out of the box. As for using a green wheel and a steady hand, the green wheel is used for roughing the form/shape and a diamond or borazon wheel is used for final dressing.

http://www.mvalues.com/pict/144181.jpg
http://reliabletools.cachefly.net/it...F10/mf11zb.jpg

A indexable carbide insert endmill is super simple. The inserts are pre-formed, pre-sharpened, and/or coated and ready to use. You just mount them to your lathe or mill tooling and away you go. They truly are, "Ready to use right from the box."
http://cgi.ebay.com/Kennametal-1-Ind...efaultDomain_0

[JWeb]

I see a belt drive in your future--or a bunch of broken gears. Be very cautious, lock the head, use sharp tools, and take light cuts. I have the same mill (and lathe too) and fly-cut with it when needed (can't beat it for smoothing out a big area) but only after going to a belt drive.

Thanks WaveDude. Is the belt drive preferred to the metal gear set? I'm not opposed to spending a little extra on the belt drive if it really makes the mill more robust.

And if your planning on fly-cutting a 3/4" deep slot you'll be there for days. If you have a saw--hack out most of that first. Otherwise use and end-mill to get rid of most of that and then fly-cut it smooth if needed. You'll need a properly shaped bit to get your fly-cutter up to a shoulder.

Good tip. I thought the fly cutter was to remove material quickly -- I didn't realize it was more for smoothing. How deep of a pass can I make with a 3/8" end mill on 6061 aluminum?

[WaveDude]

Thanks WaveDude. Is the belt drive preferred to the metal gear set? I'm not opposed to spending a little extra on the belt drive if it really makes the mill more robust.



Good tip. I thought the fly cutter was to remove material quickly -- I didn't realize it was more for smoothing. How deep of a pass can I make with a 3/8" end mill on 6061 aluminum?

Belt drive is highly recommended--along with the air-spring conversion. You won't break the metal gears but there are a couple of plastic gears that are still prone to breaking. If you're lucky, the intermediate gear on top will break--otherwise you have to take the had apart to get to the one inside. Buy the air-spring kit from LMS (can't beat it for the price and you get a longer rack as well) and if you have time you can build your own belt-drive--lots of plans on the net (I used Hoss's--http://www.hossmachine.info/projects_6.html#belt%20conversion).

"They" say you can make a pass 1/4 to 1/2 the diameter of the end mill but not with these tiny machines. I think the most I've done with a good 3/8 end-mill is about .050. I've not been adventurous enough to try more yet. Go by sound and feel more than the recommendations you get on the web. If the machine is vibrating or it feels like it's having a hard time--back off some and try again.

[MrWild]

With an X2, take no more than .05" per pass if full cutter width. Although jst less than 1/16" per pass, you can feed aggressively. If the cutter starts slowing down, ease up on the feed or you will blow the plastic gears. Use a bit of WD-40, kerosene, used engine oil, or even lard to help keep the cutter free of stuck chips.

[gmfoster]

Holy cow. Who is the Lead man in your shop? I honestly don't want to sound disparaging. NO, you do NOT use them right out of the box. As for using a green wheel and a steady hand, the green wheel is used for roughing the form/shape and a diamond or borazon wheel is used for final dressing.

http://www.mvalues.com/pict/144181.jpg
http://reliabletools.cachefly.net/it...F10/mf11zb.jpg

A indexable carbide insert endmill is super simple. The inserts are pre-formed, pre-sharpened, and/or coated and ready to use. You just mount them to your lathe or mill tooling and away you go. They truly are, "Ready to use right from the box."
http://cgi.ebay.com/Kennametal-1-Ind...efaultDomain_0

Actually they are meant to be used right out of the box. And a green wheel isn't really a suitable of grinding them you really need slow speed and diamond. The only reason to grind out of the the box would be to change the radius. You can do that pretty well with a little diamond embeded hand stone.

[mwood3]

we can save you $$$$$$$$$$$$$ we have inserts and cutters most fully interchangeable with Kennametal. We are adding thousand of items daily


There is no reason to dress inserts are ground honed and usually coated ready to use from the box.
http://www.carbideanddiamondtooling.com

Best Regards
Marty

If you are going to advertise your business in this fashion at least post the relevant link pointing directly to the item the thread is discussing...otherwise its just spam...saw 2 of basically the same post from you this morning in 2 different threads...im sure no one minds as long as you are pointing us to what we are discussing and not just promoting your site in general...

[CNCBoss]

I'm pointing out the obvious here but, remember when grinding your tool bits keep them cool. Don't burn the edges or you will lose tool life. I keep some water close at hand and dip my tool regularly. Keep it cool!

[Davo J]

Well, that's embarrassing! I guess the only reason it cut was because it is aluminum vs. HSS. Thanks so much to all who posted tips and advice -- everything is very useful.

Do the indexable tools work almost as well as the real deal? Do you have to orient the cutter at an angle at the end of the shank in order to urge it to work well swinging in an arc (as opposed to in a straight line on a lathe)?

Off to grind some tools!

Don't worry about it, at least you are willing to have a go.
This thread should give you all the info you need. HSS will give better finishes than carbide and is a lot cheaper. All you need is a 6-8inch bench grinder.
http://madmodder.net/index.php?topic=850.0
Feel welcome to join in if you want.

Dave

[Kingjamez]

I'm pointing out the obvious here but, remember when grinding your tool bits keep them cool. Don't burn the edges or you will lose tool life. I keep some water close at hand and dip my tool regularly. Keep it cool!

Why? I've heard this said before, and it is true if your not wearing gloves and holding the tool by hand. But HSS isn't hurt by heating it up, in fact it grinds better when very hot. The ENTIRE POINT of grinding it is to remove metal from the tool. That is not the case when doing cutting operations, which is where I think people get the idea of keeping the tool cool.

In fact if you dip the hot off the grinder tool in water, then you risk shocking the HSS and that will truly do harm. So either keep it very very cool always (near impossible) or just grind it hot.

-Jim

[kawazuki]

Why? I've heard this said before, and it is true if your not wearing gloves and holding the tool by hand. But HSS isn't hurt by heating it up, in fact it grinds better when very hot. The ENTIRE POINT of grinding it is to remove metal from the tool. That is not the case when doing cutting operations, which is where I think people get the idea of keeping the tool cool.

In fact if you dip the hot off the grinder tool in water, then you risk shocking the HSS and that will truly do harm. So either keep it very very cool always (near impossible) or just grind it hot.

-Jim

Forgive me if i'm incorrect as i'm no metalurgist but i've always heated metal - copper, steel etc up to a high temp and cooled it slowly to anneal it and make it soft! For steel cutting tools I would expect the reverse to be required ie they are quenched quickly to temper the steel and give a surface hardness? I assume tool steel is pre hardened so keeping the grinding temps down preserves this ?
ps. I likes inserts - does away with this aggro!

[gmfoster]

Forgive me if i'm incorrect as i'm no metalurgist but i've always heated metal - copper, steel etc up to a high temp and cooled it slowly to anneal it and make it soft! For steel cutting tools I would expect the reverse to be required ie they are quenched quickly to temper the steel and give a surface hardness? I assume tool steel is pre hardened so keeping the grinding temps down preserves this ?
ps. I likes inserts - does away with this aggro!

Well with copper it makes no difference how you cool it. Heat softens copper and brass period, don't mater how you cool it. . The only way to harden copper is to work harden. People read a little about hardening plain old carbon steel and think it applies to everything.