EMG-12 Endmill Re-sharpening module

[John Stevenson 1Participant @johnstevenson1]

One small step for Jason ?

[Howard LewisParticipant @howardlewis46836]

Thanks to all who provided details of where to get End Mills sharpened.

Will follow up in the near future.

Howard

[Neil WyattModerator @neilwyatt]

> As JohnS has pointed out endmills and slot drills are slightly hollow ground, but only by about 1°. So for a 2 thou advance that's a height difference of about 35 microinches or about 0.86µm.

Google suggests a bit more than that is typical, up to 2 degrees, about 1.7um? Still about half your figure.

Neil

[Anonymous]

Posted by Neil Wyatt on 04/06/2015 21:15:36:

> As JohnS has pointed out endmills and slot drills are slightly hollow ground, but only by about 1°. So for a 2 thou advance that's a height difference of about 35 microinches or about 0.86µm.

Google suggests a bit more than that is typical, up to 2 degrees, about 1.7um? Still about half your figure.

Remember that we're calculating a peak-to-peak value, whereas I am measuring an average value. So, depending upon the crest factor, the calculated values are much smaller than those measured.

Andrew

[JasonBModerator @jasonb]

So as its been about a month since MEW232 came out has anyone got any comments on the results from this little machine that were in my review?

Have any members been tempted to raid the piggy bank?

Could have done with one myself the other evening when I hit a hard spot while milling off some weld that took the corners off a sharp 1/2" cutter

[Anonymous]

Posted by JasonB on 13/09/2015 08:05:17:

So as its been about a month since MEW232 came out has anyone got any comments on the results from this little machine that were in my review?

Have any members been tempted to raid the piggy bank?

In a word, no and no.

However, since I had the opportunity to try out the unit a while back I thought I ought to finally extract my digit and write something up. First impressions were good. The machine is nicely made, the instructions are well presented, and I had no trouble getting it up and running. The motor controller is slightly odd in that when switched on the motor oscillates, as if deciding which way to go, before the motor spins up to speed over a couple of seconds.

I didn't try the machine with HSS cutters, as the few that I have that need sharpening were too big. However I did have a range of uncoated carbide cutters in various states of disarray, from simply blunt to having corners knocked off due to operator incompetence. For the tests I had 2mm and 4mm 2-flute slot drills and several 6mm and 10mm 3-flute slot drills. Where the slot drills were badly damaged I first removed the damaged length using a bench grinder with a 'green grit' wheel.

I found the instructions easy to follow. For some of the larger cutters several passes were needed before all the cutting edges were properly ground. This may be because I hadn't taken enough care when roughing out. I was impressed by the rate at which the grinding disc removed the carbide. I found the 6mm and 10mm cutters easy to sharpen and the fresh cutting edges look really good. For the 2mm and 4mm cutters I had some trouble lining the edges up correctly, so that the finished edges, although properly ground didn't seem quite right? Since I only had one each of the 2mm and 4mm cutters to play with this may well be operator error. I haven't had the chance to try the re-ground cutters in anger, but have no doubt they will be fine.

So in summary the unit does exactly what it says on the tin and is simple and quick to use. It is very good for regrinding blunt, or damaged, ends of cutters. Of course the big question is would I buy one? Probably not, although that is no reflection on the unit, for the following reasons:

1. I tend to make heavy use of the side flutes when milling so the side flutes often end up damaged, more so than the ends. The unit is unable to regrind side flutes.

2. Most of the HSS cutters I use are bigger than the 12mm limit of the unit.

3. I already have a well equipped Clarkson T&C grinder for regrinding and modifying cutters.

Andrew

[Ketan SwaliParticipant @ketanswali79440]

There were various comments made on this thread about the limitations of EMG-12 with reference to the end mill size range this module was able to handle: 3mm to 12mm.

The factory which makes the above, also makes the size which covers a range from 4mm to 20mm. However, just like the EMG-12 pre JS intervention, this model needed a little modification. After JS's input, ARC has now added this modified version to the range too, offering EMG-20, in addition to the EMG-12.

General detail on this page.

JS will be doing demonstrations at the Doncaster Show.

Ketan at ARC.

[JasonBModerator @jasonb]

Ketan, any details of the drill sharpener JS says he will also be playing with demonstrating?

[Ketan SwaliParticipant @ketanswali79440]

Posted by JasonB on 11/05/2016 18:32:11:

Ketan, any details of the drill sharpener JS says he will also be playing with demonstrating?

Hi Jason,

JS is still playing with it. There are a few issues with it which need ironing out before we go anywhere with it.

Ketan at ARC.

[John Stevenson 1Participant @johnstevenson1]

Jason,

As regards the drill grinder we are now on the MK3 as regards modifications but this is only on the drill grinder module.

There are two modules to it, the drill grinder and the point thinning. The grinder is now working very well and I'm pleased with it but the point thinning leaves a lot be be desired, depending on diameter the results are variable and it needs more work on this part. The book that comes with it is useless and I'm certain it doesn't even apply to the machine I have but this will get re-written in the UK.

The drill grinder is quite unique in that normally you can grind drills two common ways, a swept point as I call it which is what most commercial drills are ground because of speed, and 4 facet grinding which is better but slower and takes more skill in setting up.

This new grinder does the first part as a 4 facet and then sweeps the clearance angle back all in one fast operation.

The change over point is very, very subtle and it hardly noticeable, it shows up as more of a shadow on the drill as opposed to a step. So far we are very pleased which what we are seeing and the support from the factory on this has so far been impressive.

I'll have the prototype drill grinder at Doncaster and will be grinding drills from 3mm up to 20mm, parallel or taper shank but not point thinning at this point.

[SteveIParticipant @stevei]

John,

Is the drill grinder based on the Christen concept?

Steve

[John Stevenson 1Participant @johnstevenson1]

No, in some ways it operates similarly to the EMG series of grinders in that all the skill needed is built into the machine and didn't rely on the skill of the operator.

I have a similar machine to a Christian a German Meteor and whilst being a very good machine, ease of use isn't at the top of it's list.

Where this range of sharpeners score is that they are very fast which allows you to sign lick a cutter or drill up prior to use or to put them away sharp

[John Stevenson 1Participant @johnstevenson1]

Just to bump this up to the top and let people know in this thread that i will be running these machines at Doncaster this coming weekend grinding cutters for anyone who brings any.

Range of end mills or slot drills is 4mm to 20mm in 2,3 or 4 flute, HSS or carbide.

Same applies to drills on size 4mm up to 20mm in HSS or carbide , parallel shank or taper shank.

Please keep the selection to a maximum of 8 to allow everyone to get a chance. No charges for this servive but the organisers who are supplying the stand will have a charity box on the stand.

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