WCD milling pockets for bearing blocks

[Cory]

Originally Posted by TD78

Any particular type of end mill recommended? Brand? Carbide vs. HSS? I used HSS last year, but never needed to have an LOC longer than 1/2". Is carbide the preferred alternative for rigidity in this case?

Also, maybe slightly off topic, but any recommendations on reference books/resources for workholding? That seems, to me, to be the biggest hurdle to get over. My team acquired a used CNC mill last year and while it took some time to learn how to operate it, fixturing was the hardest part.

We use carbide almost exclusively unless it's a tool too large or uncommon to justify the increased cost. For small end mills the price differential is so small it's not worth it to buy HSS. We purchase almost all of our end mills from lakeshorecarbide.com. Made in the US, very high quality/performance at a great price.

Fixturing was our biggest struggle when we first got our CNC mill. We kind of just got experience with it as we went and did more things. There are books I've heard recommended but they're all $100-150. Practicalmachinist.com is a great site for metalworking forums. You can search for fixture designs or workholding tips and see a lot of great examples of how other users have done things, or you can get advice for your own parts you may be having trouble with.

[scottandme]

Carbide is more rigid and can run at much higher SFPM, but your operation doesn't really need that - pocketing in 1/8" aluminum should be pretty easy, and a 1/2" HSS end mill is going to be plenty rigid for almost all operations on a manual mill. Carbide is really better suited for CNC machines with higher RPM spindles. Just stick with a larger diameter tool with as little stickout as possible (to mimimize tool deflection). HSS is more forgiving anyway if you're running the machine manually.

McMaster sells Niagara end mills, something like #2716A71 ($25) would be about right. The Lakeshore carbide end mills do have a good reputation, and are very reasonably priced for carbide tools ($48 for the ZrN coated 3 Flute EM).

Agree with Cory that using a workstop or indicating the part after you flip it should be plenty accurate anyway.

[Cory]

Originally Posted by scottandme

McMaster sells Niagara end mills, something like #2716A71 ($25) would be about right. The Lakeshore carbide end mills do have a good reputation, and are very reasonably priced for carbide tools ($48 for the ZrN coated 3 Flute EM).

This brings me to my second favorite metalworking supplier. Maritool. Fantastic prices on toolholders and pretty good deals on cutting tools. We buy all our collet chucks/end mill holders/milling chucks from him. Unbeatable for the price. No performance difference between his stuff and holders that cost 1.5 times as much. All his toolholders are made in Chicago in his shop. His collets are from overseas, but most of the rest of what he sells is made in the US.

That same half inch end mill (with 1.0" LOC) that you mentioned is only $4 more from Maritool in carbide. On a manual mill I wouldn't bother with it, but on a CNC I nearly always find carbide to be a better choice and would pay 15% more any day.