Feeds and speeds for a shell mill

[Paul LParticipant @paull58212]

Thank you all for your advice and experiences.

A couple of things I’ve learned from this thread.

• I’ve got a SX3 mill not a 2.7 🙂
• The feed rate is important so I’ve fitted the RLS scales I made 4 years ago and the DRO which shows  feed rate.
• Keeping a constant feed rate is not easy, so im in the process of making a power feed. (Ketan you forgot to send me one!)
• The correct inserts for the material are important so an order to ARC for uncoated inserts and a 80mm shell mill is in the pipeline.
• I’m in no hurry when im working so massive DOC are not important.
• Im non the wiser about what DOC , RPM and mm/min  to use for what material etc. Is there an online calculator or something to make this simple?

Thanks again for all the help.

Paul

 

[JasonBModerator @jasonb]

The majority of online calculators are based on commercial size machines with more power and rigidity so can only be taken as a guide for the benchtop hobby machines. Little Machine Shop is about the only one specifically for hobby machines.

The Milling for beginners series that I did in MEW and is what my book is based on ended before I got to go into this subject but I’m going to write something up based on what suits the hobby machines which is generally running on the fast side of cutting speed, less DOC and a chip loading that won’t stall or flex the machine yet is still enough to stop rubbing. Will likely be in MEW and I will probably add it to the “workshop” section of the site. This will cover shell/facemills as well as solid milling cutters.

As for getting the job done in a certain time it is really no slower to take several shallow cuts at high feed than it is to make one slower deep cut

[old martParticipant @oldmart]

Shell mills are commonly used in industrial applications much faster than manual mills can achieve. I have a Ceratizit 50mm five insert shell mill which takes proprietry RCMX10 inserts which look like the common round ones. Max rpm is 11500 and according to the Ceratizit website after indexing round all 8 places and changing the set of inserts, the screws should be replaced also when max rpm is used. I am still on the original screws after many years, but 3000rpm is the maximum speed that the Tom Senior light vertical will go and the round column mill will only manage 2400rpm. A powerful CNC mill would be needed to drive one of these at the maximum cutting rate.

I agree with Jason regarding several light cuts rather than one deep one.

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