I Need Advice From a Journalman Machinist

GUEST has it right

Thank you. If I use end mills with a Tin or cobalt coating, will it be a real improvement? I machine mostly aluminum; some 1018. Will I see a difference between using a $10 import 3/4" 2-flute vs a $30 American end mill in quality of cut or life?

Hi Ronseto,

If you are machining aluminium high speed steel cutters will give you the best performance for your $ and generaly a better finish. As far as HSS end mills go American quality will generaly be better but some imports are as good.

I am using some Chinese replacable tip end mills, these take standard ISO tips so I can use cheap or expensive tips to suite and have no complaints re quality.

Ultra interesting! Many, Many thanks Garth.

Here are some online resources for home machinists:

https://www.chaski.org/homemachinist/
http://bbs.homeshopmachinist.net/

There are also a few Yahoo Groups for specific machine makes (Logan, Sheldon, etc.)

It's not so much the cost but the design and rake angle and relief that's put into the insert. There are different tools for different material's. For the most part I do not use imports for this reason...they are usually made in China and are made from a lower quality steel or carbide and you never know what the grind is...It's pot luck. A Titex or Kennametal cutter will out last 5 or 6 of the import cutters or inserts...in my experience. And you can have them ground for Mag ,TI or any of the exotics.

If you are getting chipping on your inserts you might be picking up vibrations which would mean your machine is not rigid enough or your toll post ...or your speeds and feeds might be to fast for the material or your cut increment is to deep...tool could be off center in the wrong direction. There are a number of reasons for that.

HSS is more forgiving than carbide it's just to brittle...everything needs to be just right...all your variables come into place when using it.

I would stick with what works for you in your situation and just use a better grade of HSS steel tooling from a company that is reasonable and you can trust.

Good Luck my friend.

If You are chipping carbide bits Your machining technique is the problem. carbide bits, especially for the lathe is the way to go. If you have a grinder, which You should have, all You need is a green stone(made to grind carbide tools) to sharpen the bits.

I have found that the cheaper imports can do an admiral job considering they are a lot cheaper then usa made. Go to google or yahoo for any questions on machining techniques. also You might want ot subscrbe to the "HOME_SHOP MACHINIST" a very good magazine foir hobbiests.

oilcan13

I suggest you contact a local tool distributor. In past experiences with them, them not only will suggest proper tooling but also a cutting fluid. Many times we've changed cutting fluids and used the same tooling with measurable a difference.

Hi there,

Use HSS tool bits with 13-18% titanium content.

When using HSS you may stop the lathe with the tool engaged and then proceed without damaging the cutting edge however not with carbide as it will chip.

You don't specify what type carbide tooling you've tried. in-expensive brazed on carbide chips are generally of low quality; C-2 to C-4 grades. Though these grades can last well when mounted in a fly cutting tool for aluminium HSS would offer greater range of speeds and feeds, etc..

Here are some Kennametal styles you would find useful (lathe) for both OD turning and boring:

Screw-on mount DCMT-MF / Grade KC9125 - this will suit your equipment well for general machining and yet provide a good finish too for 1018 and aluminium.

Clamp mount VNMS-E/F 160404E / Grade KC9125 same as above

TNMP-K 160404K / Gr KC9125

DCMT-MF Gr KC9125

http://www.kennametal.com/images/pdf/US/Sections/KMTL-Lathe_Tooling_Catalog_4010/KMTL-lathe_4010_complete.pdf

http://www.kennametal.com/images/repositories/PDFs/A07-297_OD_expanded_small_parts.pdf

The Kennemetal insert holding tools are a good choice though I would adapt a tool holding block design rather than the standard tool post.

End mills: Carbide tooling won't be cost effective for your equipment capabilities. Unless you're cleaning torch cut pieces then a carbide insert shell end mill may be prove cost effective and is possible to use the same inserts as for turning too.

2-flutes are great for plunging

4+ flutes move things along and better finish.

Coatings won't gain you much because after the first sharpening it's kaput a better grade of HSS is more helpful.

Yup

B's got right

you can't reproduced the shape of an indexable cutter. I like 3 sided, which yields 6 good cutters

the sharper the tool the slower the feed the better the finish [just a rule of thumb]

if you chip an indexable cutter you can change a tip without losing your set up.

a mister is by far the most effective thing you can use for keeping the tool cool...

spend some time taking the free play out of especially the cross feed. there is probably a tapered wedge you can adjust. Clean, tight & lubed.

The chuck probably has a tapered bearing, it can be damm near impossible to to get a decent finish if the chuck is loose. Don't forget the tail stock & live center

Right-O and the "Aloris" tool post ensemble is a sweet deal too...and well worth the $

http://www.aloris.com/

A quick change make's it all go much quicker, I love quick changes, being able to switch from tool to tool in seconds, allows you to make short work of multi part runs. in combination with indexable cutters, it's a different experience.

A good trick for getting the tool height set is to chuck up a piece of round,

hold a piece of flat bar or sheetmetal up next to the round,

slowly crank the cutter in until it traps the sheetmetal against the round

the angle of the sheetmetal compared to the round, will give a visual indication of the level of the cutter.

depending on the round, you may want to take a cut, drill a center & try again

Compare right against the chuck & right against the tailstock... you may be suprised how far off the tail is.

this can also give indications of how true the bed is

To check the tailstock & centers

do a face cut as close to the chuck as possible [another way to check tool height]

install a center in the tail, slide up to the chuck, lock, compare

even a old worn out economy lathe can produce high quality parts, with careful adjustment & understanding where the problem areas are

The quality of machining is dependent on many factors such as:

Style and selection of the cutting tool and the material of the tool.

The hardness and the abrasiveness of the material that you are cutting of it is a big factor in tool life.

Having a rigid or well supported setup.

Proper feeds and speeds for the above.

Machining process or sequence.

How the cutter is applied to the part: Climb mill, conventional mill, side mill, direction of cut, direction of cutting forces, width of cut in relation to the cutter diameter, step over, depth of cut, rigidity of milling machine. Vibrations and any harmonics in the part while cutting.

I work in aerospace and with the exoitic metals, I find that usually the cheap carbides just don't cut it.

If you are cutting mild steel or aluminum look into the other factors, if you don't then the more expensive won't help you much. Improve your other factors first before you spend the money on good tools.