Thread: Economical Milling

Hello all

I recently purchased another product from a company called Eccentric Engineering. I am a happy customer as his products work as advertised. They are also economical to use in my opinion as they are easy to sharpen, and you get a lot of use out of each cutting tool. These tools have opened my eyes to economical home machining. I can see they would not be practical in a production shop, but my labour rate is virtually nill compared to a business.

I have also recently purchased a mill (HM46 look alike).
I am after some advice on economical tooling. Is there easy to sharpen tooling that I can use instead of hard to sharpen mill bits?
What is the most economical way for end mills and where is a good place to buy? I am in SE QLD and have noticed some places have very high postage costs compared to others. Please not I am after economy, which is in my mind different to cheap. I can probably find a cheap $2 end mill but it may on last 2 minutes, where as an economical end mill may be $20 but lasts 2 hours. Assume I know nothing as sometimes the most basic idea is overlooked.

Thanks
Steve

Originally Posted by Reidy41

I am after some advice on economical tooling. Is there easy to sharpen tooling that I can use instead of hard to sharpen mill bits?

As far as I know, your options for milling are spiral endmills (cheap to buy, hard to sharpen) or carbide insert tools (easy to sharpen, comparatively expensive)

What is the most economical way for end mills and where is a good place to buy? I am in SE QLD and have noticed some places have very high postage costs compared to others. Please not I am after economy, which is in my mind different to cheap. I can probably find a cheap $2 end mill but it may on last 2 minutes, where as an economical end mill may be $20 but lasts 2 hours.

Trade school was using endmills from this mob https://www.ausee.com.au/shop/category.aspx?catid=1068
They seemed to cut well (before the numpties destroyed them) and the price is not outrageous.

Wrong feeds/speeds will drastically shorten the life of any tooling (too slow RPM/fast feed and they chip, too fast RPM/slow feed and they burn up), so I'd recommend downloading FSWizard (free on Android, iOS or PC) as a guide.

I'm not a big time user but I've used the Ausee ends mills and they seem OK

It doesn't always suit but I've found I can do quite a few things using a small fly cutters for which the tool tips can be easily resharpened.
Eg https://www.ausee.com.au/shop/item.aspx?itemid=3707

Originally Posted by BobL

I'm not a big time user but I've used the Ausee ends mills and they seem OK

It doesn't always suit but I've found I can do quite a few things using a small fly cutters for which the tool tips can be easily resharpened.
Eg https://www.ausee.com.au/shop/item.aspx?itemid=3707

Hi Guys,

I have to agree with Bob, for 90% of the milling that I do a fly cutter is my tool of choice ! I've done all sorts of things with a fly cutter from simple facing to cutting recesses and dovetails.

Here is a picture of one of mine...

New_Flycutter-1.JPG

Dead simple to make and takes advantage of almost any broken bit of HSS. The piece in that is 1/4" square HSS and about 30 mm long. Dropped into a round hole and secured with a grubscrew.

BaronJ

I would be interested to know how you cut a dovetail with a fly cutter. No doubt it is simple once I get the concept.

I am suspecting the fly cutter is one of those mill tools that is a lot more versatile than it looks but does not get the credit. Probably because it is a single point HSS cutting tool. Maybe I should start a new thread devoted to fly cutter lovers and all of the cool things they can do.

Steve

Originally Posted by Reidy41

BaronJ

I would be interested to know how you cut a dovetail with a fly cutter. No doubt it is simple once I get the concept.

I am suspecting the fly cutter is one of those mill tools that is a lot more versatile than it looks but does not get the credit. Probably because it is a single point HSS cutting tool. Maybe I should start a new thread devoted to fly cutter lovers and all of the cool things they can do.

Steve

Hi Steve, Guys,

One of the design concepts for the fly cutter that I posted a picture of, is rigidity ! Flexing is a problem with a fly cutter. The larger the radius that you need to cut the more the cutter flexes. So mine is on the biggest shaft size that I can hold in my milling chuck, which is 20 mm diameter.

The body is also 20 mm thick ! As it happened an offcut from a stainless steel bar end, I just cleaned it up in the lathe and drilled it for a press fit for the shaft. The hole for the tool bit is 8 mm in diameter to hold a piece of 1/4" HSS tool steel.

The purists will point out that a square tool bit will have to be angled slightly because the cutting edge will not be quite on the centre line.

This drawing describes how to fix that ! Note a round tool bit doesn't have this problem.
Fly Cutter 01.png
The grub screw is angled very slightly to twist the tool bit a few degrees. However I've never found this to be a problem because you can grind the correction into the tool side rake, just like a lathe tool.

I don't think that I have any pictures of the dovetail cutter that I made, but there are two ways (techniques) for cutting them.

The easy way is to machine the female side in one long piece to make single piece of material long enough for the job and then cut it in half to get the sides. The other is to make the cutter small enough in diameter to be able to fit into the initial slot. But you do need a slot drill to cut the slot first.

22-04-2020-005.jpg

I made this dovetail slide using the first method described above. The only advantage is that you don't need a gib strip. The play in the screw holes allows you to set the slide however you want.

Somewhere I have some pictures of the flycut dovetail and slide that I made using the fly cutting technique.

Sorry for the long post !

Originally Posted by Reidy41

Maybe I should start a new thread devoted to fly cutter lovers and all of the cool things they can do.

Steve

Fly cutter challenge, wouldn't that be interesting!

Originally Posted by NedsHead

Fly cutter challenge, wouldn't that be interesting!

Hi Ned, Guys,

I like that idea ! It would be really interesting to see them made and ground !

The dovetail cutter that I made long ago was turned from Silver steel and milled to form cutting edges before being hardened and sharpened. Single point cutting a dovetail is a very slow job !

I am far from the most knowledgeable mill operator, but my take is that single point HSS tooling is at it's best for one off, specialised jobs. For example, take a fly cutter of 80mm diameter with a single cutter and compare it to a carbide face mill of the same diameter with 4 inserts. Working with mild steel at a 2mm depth of cut, the fly cutter will achieve something like 3.5Cm³/ min material removal rate and absorb .1Kw to achieve that. The indexed face mill will remove 66Cm³/min, but take 1.9Kw.
Two extremes, but the relatively poor performance of single point HSS tooling must also be factored in to the economy equation.
Sometimes we're better off to bite the bullet and buy the right tool, learn to maximise it's life and pay for it to be sharpened or replace it. Lathe users can get away with much more than mill users as the only have three angles to worry about and the tool is stationary, mills have far more involved geometry.