Using small endmills on Sherline 5400

[Aaron_W]

So I'm finally about done setting up a work area so I can break in the new mill.

With the sizes of things I want to make I really need to use small endmills. I know it has been mentioned that small endmills like high speeds, higher than the 5400 provides (2800 rpm). So granting that they may not be happy with this, I'm looking for suggestions on how to make them less unhappy. Assuming lighter cuts and slower feed rates should help. I know a few mentioned successfully using small endmills at below recommended speeds.

I've got 2 flute square and ball end end mills from Shars. HSS sets in 1/8-1/2" as well as individual 1/16" and 1/32" carbide (I couldn't find these sizes in HSS).

I will be milling aluminum, and possibly brass.



I have a second question related to the larger HSS cutters. I bought 2 flute cutters as I plan to predominately mill aluminium and 2 flute seems to be preferred for that. Will these be ok for occasional use on mild steels as I might use to make a tool holder from or should I keep the 2 flute exclusively for use with the softer materials, and pick up some 4 flute end mills when I have a need to cut some steel?

 

[kvt]

One mod you can do to increase the speed. they make a 10K rpm set of pulleys for it.
Other than that just adjust your feeds and speed like you said. I have 4 flute endmills for mine and I know that my father in law used very fine ones with it before He passed and I got it. Another thing to do is cutting fluid sill help keep it from building up on the tools.
Just my 2 cents worth.

 

[mikey]

Aaron, I mostly use cobalt hi-helix end mills for aluminum with my Sherline mill, although HSS works great, too.

The thing with milling aluminum is chip clearance and hi-helix end mills work really well for this material. I almost always use roughing end mills before using a finishing end mill unless the cut is superficial - fine for profile work and coarse pitch for pockets. Your finishing end mills will last a long time if preceded by a rougher.

I haven't used Chinese end mills so have no opinion. I use Niagara, OSG, Brubaker, Regal and other quality makers and their stuff works well on a Sherline. I prefer 2 and 3 flute for most work but will go to a 4 flute for finishing cuts, especially for steel. I tend to choose the number of flutes based on the cut; fewer when chip clearance is a concern, like in a slot or pocket and more when finish is concerned. If you buy standard uncoated end mills, they will work with steel, aluminum and brass. I have some carbide end mills but don't use them much unless I'm working with some hard stuff or when I need to profile something accurately and can't have too much flexing of the end mill.

With regard to speeds, use what you have. Many times, you will be running at max speed, especially with smaller end mills. What you have to learn is how a properly cutting end mill sounds and feels like. When the feed is right there will be a slight resistance to the feed as you turn the hand wheel.

 

[Aaron_W]

Yep, I'm considering the 10,000 RPM pulleys in the future, but I need to start making stuff before spending more money. Also not sure even that is fast enough, when I asked about using Dremel bits many of which are in this size range it was pointed out Dremels are capable of 20-30,000 rpm.

I'll see what I can do with it stock and go from there. Everything I've got planned is well within even the most conservative limitations of the Sherline equipment, so if taking light cuts and going slow does the job it won't be that much of a hardship. The larger projects I'm looking at are in the 1" dia range, with many of them starting off with 1/2" or even 1/4" rod.

I got the Shars endmills because they were cheap and seem to have decent reviews. Once I have a better idea of what I'm doing and what sizes I need for the work I'm doing I will invest in better quality endmills.

Thanks