Sharpening Milling cutters

[Bob McParticipant @bobmc91481]

Hi Paul…

I wrote an article for MEW in November 2015, No 235. The design uses 2 Arduino's which were coupled together so as to provide synchronism in providing pulses for the stepper motors, however it is not necessary to electrically couple them and I am assured that if the Arduino's have proper Xtal signal sources you can use them as they are.

The program could not be simpler for the Ard's … it uses the Blink program and the article describes how to find the correct pulse times, there is also a circuit and explanations, someone with a small knowledge of Arduino programs could easily set it up. I can give you the progs no problems.

There is a Spindle speed program which just runs the Blink sketch continuously and there is a Leadscrew motor program which has an interrupt control to start the Leadscrew motor at a specific point in the spindle rotation.

I have used this lathe many times for making screw threads of various pitches, some quite peculiar for telescope eyepieces and suchlike, but the beauty of the system is that you can adjust the parameters for virtually any pitch you want, the only drawback is that my spindle motor is not as powerful as I would like, you could even vary the pitch within a pitch … there is absolute full control over this.

The system however does not have any feedback and relies on the start pulse to set it running, if there is too much load for the motors there will be problems so light cuts are needed, in the case of a grinder for milling cutters there would be no problem.

Bob.. -.- -.- -.-

[John PParticipant @johnp77052]

Posted by Paul White 3 30/06/2019 13:22:09

I would like to ask how you measure the helix of the cutters for sharpening.
I have tried all manner of devices (mechanical ) but have failed miserably .
The area I am trying to address is that of sharpening the sides of small end
mills when the usual mechanical guide does not work.
your use of an electronic solution looks to the answer but the helix variation
has me stumped.

An article that was in MEW 143 through to 147 "A cnc cutter grinder "
may be worth a look,it describes the construction of a machine and its use.
The photo here shows a 3/4 inch long endmill and a 3 mm 3 flute carbide
endmill alongside ,both have been sharpened on this machine.

It is important that the cutter should follow the original lead of the cutter, as
can be seen the lands on the large cutter form a parallel edge along the length
of the cutter,any deviation from this would mean the clearance angle would
change or the cutter would become tapered.
Some cutters have the lead engraved on the shank ,as can just be seen
the imperial cutter is marked 5.440 inch and the metric has 56 next to the
small triangle indicating the lead is 56 mm.

Much more sophisticated machine seen here…

http://www.youtube.com/watch?v=qxU0K-TmEvI

They use the same method as i do to measure the cutter but their
system is much easier to use.

John

[Paul White 3Participant @paulwhite3]

Bob.

Thanks for your helpful comment, I will try to

get a copy of your article .

John,

Thank You for your helpful input . More to source and read.

Paul

[Author]

Posts