Why every hobbyist should own a 14mm end mill

[samuel heywoodParticipant @samuelheywood23031]

….Every hobbist that owns a milling machine at any rate.

Just a little tip for anyone who hasn’t realised.

One of the quirks of end mill sizing is that the 14mm end mill (& the less common 13mm size) has a head diameter larger than the shank diameter. (HSS/HSSCO  end mills)

When side milling this can be put to your advantage.

You can take a pass, then lower the head & mill another pass without the shank rubbing, like it would with say a 12mm or 10mm end mill.

Thus enabling you to deal with quite thick pieces of work, certainly a fair bit more than the flute length….

& yes even my Sieg X1 copes with a 14mm end mill, sure the DOC isn’t massive, but it’s a way to get the job done.

Hope that helps someone.

 

 

[Mark RandParticipant @markrand96270]

Never noticed that before. Thanks for the tip. 🙂

[JasonBModerator @jasonb]

You can buy quite a few sizes with reduced shank but beware that chatter is more likely.

Another option which is meant for the use you describe are the reduced neck milling cutters which have an area above the shank reduced in diameter but are full diameter on the plain shank. I’ve not had chatter issues with these. I’ll take a photo when I’m in the workshop later

Insert shell mills will also allow similar milling operations

One word of caution if using a 14mm with 12m shank is that you should where ever possible have the minimum of stickout so if possible put the 14mm close to the end of the collet. A long series cutter will allow you to reach further while still leaving sufficient shank in the collet.

[Another JohnSParticipant @anotherjohns]

The machinists where I once worked would take an end-mill, and grind off the top of the flutes on the side of the end-mill, leaving about 6mm (?? IIRC) of flutes on the sides to cut.

They were producing prototypes of all kinds of things; the one I saw this being machined on was for a bracket for some “device” for a hanging something on a military helicopter, so they were not “goofing” around.

I have not used this tip yet, as most of my milling in the past while has been on sheet/bar where maybe depth is 1D or 2D with cutters <=6mm, so not too deep.

FWIW – JohnS

[JasonBModerator @jasonb]

So here we have a cutter with a smaller shank in the middle, in this case a 1/2″ 4-flute on a 3/8″ shank.

The two on the right are commercial “necked” cutters, a 2 and a 4-flute where the flute only extends to where I have drawn the arrows and the rest of the coated area above is approx 90% of cutter dia so the 10mm cutter reduces to 9mm but has a 10mm shank and still has plenty to hold.

On the left are two long series cutters the main thing to noe here is that there is enough shank to completely fill a collet but when the reduced shank one is extended to a similar length you don’t have  alot to get hold of so starts to get a bit risky.

If you really want to pull a cutter with a small shank and larger flute diameter out of the collet to extend the cut then use the proper ones that have extended shanks so you maintain full grip, I don’t have any but this is the type of thing.

 

PS also check the spec before you order that mus have 14mm cutter as some have 16mm shanks and some have 14mm shanks not all are 12mm shank.

[David George 1Participant @davidgeorge1]

A while ago now I decided to make a four jaw chuck for a Stuart lathe I was making and needed a 6mm diamiter woodruff cutter to cut the jaw slots and struggled to buy one so decided to make one. A friend has a cutter grinder which made the job possible and ground one to suit slot. The cutter was ground to the slot sizes with no clarance and the cutter head was finnished thickness so one cut through to finnished size which worked very well. I drilled a 6mm tapped hole through first and finnished the top of the slot to size first.

David

 

 

 

[Neil WyattModerator @neilwyatt]

I’ve made a such things from silver steel by turning and filing. They are far less elegant, not perfect, but work.

Neil

 

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