Pete.
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- 15,038
- Location
- Kent, UK
I bought this drill grinding machine yesterday, found it locally on Facebook Marketplace in an engineering workshop sell-up. There were a load of machines listed (all in very fair condiiton it has to be said ) which had prices listed and he was inviting offers for the smaller stuff. I saw this grinder in the pics and offered £250 and we settled on £300. These things are not common nor cheap and this was no exception but it was in good condition and had all the correct bits with it and was about the same money as a new budget drill grinder which would be a far inferior machine (not including those horrid plastic Martek type thingswhich I would never consider).
It's a Christen 05-8 however it came with the extra collet holder for the larger drills giving it a drill sharpening range of 0.5mm-10mm.
The first thing I noted was that it was a 3 phase machine - something I wasn't aware of and the guy was selling stuff for his dad so it never occurred to him. No matter I've done this before so I could either put a VFD on it or add a capacitor the same as I did on my Union grinder. in the end that's what I did - stripped the electrics out of the base, re-wired the motor for delta and put in a 8uf capacitor which wasn't quite the right size but the machine spins up at a healthy rate and doesn't get hot after an hour of running so I'm happy with that. I aslo had to get rid of the 415v-6v transformer that powers the lamp because I'm feeding it with only 230V and the lamp was very dim like that. I have got around it by poking the wires into a small DC charger for now whilst I figure out what to do - it'll probably be a small LED torch like I used in my Hilger & Watts microscope.
After that I dismantled the machine and cleaned it up. It really only needed a wipe-over but the moving parts were a little gummy especially the drill holding collets so it was all stripped and de-greased then fresh oil and grease applied.
Here's the scale for the point angle and the rotary scale for the primary relief angle all cleaned up and easy to read.
Here's the collet holder attachment for the smaller drills (0.5mm-6.35mm). The pivot is at the bottom, which holds the indexing collet on the left which in turn clamps the drill-holding collet holder on the right. In the box you can see the different collets, the dressing siamond and the little feeler gauge for setting the grinding wheel distance. You can see this all assembled in the first pic.
First job was to dress the wheel. I put the dressing diamond in the pivoting holder and set the end into the little bracket they give for the job and swing the diamond across the wheel to true up the face.
After dressing, the wheel distance has to be set. i have discovered that this is quite critical and they give a little feeler gauge in the box to do the job. you loosen the wheel hub so it's free to slide then bring it up to the drill tip guide holder and set the gap with the gauge (8 thou).
Then set up the first drill for sharpening. Luckily, you can download the manual for the machine from Christen so I just followed the instructions. The initial grinds looked pretty good but I was getting much larger primary cutting edges than you would like - the two vertical grind lines are supposed to meet in the middle. Tjis drill did do a nice job of cutting but it needed some adjustment.
After some adjustments I was getting a good grind on both sides and the line between primary and secondary grinds were now lining up. It's not true for all drills though I have a huge assortment of all brands and quality and some of them definitely are much more poorly made than others. This is about a 5mm drill:
And this is a slightly out of focus 1.5mm drill which is about the smallest I can sensibly grind with this grinding wheel fitted. I am going to order some more wheels when I find some suitable ones (coz the Christen ones are stoopid money).
I've still got some fine-tuning to do, there's a specific procedure for seeting up the machine using a 4mm test pin but I wanted to get familiar with it forst so I'll tackle that later.
It's a Christen 05-8 however it came with the extra collet holder for the larger drills giving it a drill sharpening range of 0.5mm-10mm.
The first thing I noted was that it was a 3 phase machine - something I wasn't aware of and the guy was selling stuff for his dad so it never occurred to him. No matter I've done this before so I could either put a VFD on it or add a capacitor the same as I did on my Union grinder. in the end that's what I did - stripped the electrics out of the base, re-wired the motor for delta and put in a 8uf capacitor which wasn't quite the right size but the machine spins up at a healthy rate and doesn't get hot after an hour of running so I'm happy with that. I aslo had to get rid of the 415v-6v transformer that powers the lamp because I'm feeding it with only 230V and the lamp was very dim like that. I have got around it by poking the wires into a small DC charger for now whilst I figure out what to do - it'll probably be a small LED torch like I used in my Hilger & Watts microscope.
After that I dismantled the machine and cleaned it up. It really only needed a wipe-over but the moving parts were a little gummy especially the drill holding collets so it was all stripped and de-greased then fresh oil and grease applied.
Here's the scale for the point angle and the rotary scale for the primary relief angle all cleaned up and easy to read.
Here's the collet holder attachment for the smaller drills (0.5mm-6.35mm). The pivot is at the bottom, which holds the indexing collet on the left which in turn clamps the drill-holding collet holder on the right. In the box you can see the different collets, the dressing siamond and the little feeler gauge for setting the grinding wheel distance. You can see this all assembled in the first pic.
First job was to dress the wheel. I put the dressing diamond in the pivoting holder and set the end into the little bracket they give for the job and swing the diamond across the wheel to true up the face.
After dressing, the wheel distance has to be set. i have discovered that this is quite critical and they give a little feeler gauge in the box to do the job. you loosen the wheel hub so it's free to slide then bring it up to the drill tip guide holder and set the gap with the gauge (8 thou).
Then set up the first drill for sharpening. Luckily, you can download the manual for the machine from Christen so I just followed the instructions. The initial grinds looked pretty good but I was getting much larger primary cutting edges than you would like - the two vertical grind lines are supposed to meet in the middle. Tjis drill did do a nice job of cutting but it needed some adjustment.
After some adjustments I was getting a good grind on both sides and the line between primary and secondary grinds were now lining up. It's not true for all drills though I have a huge assortment of all brands and quality and some of them definitely are much more poorly made than others. This is about a 5mm drill:
And this is a slightly out of focus 1.5mm drill which is about the smallest I can sensibly grind with this grinding wheel fitted. I am going to order some more wheels when I find some suitable ones (coz the Christen ones are stoopid money).
I've still got some fine-tuning to do, there's a specific procedure for seeting up the machine using a 4mm test pin but I wanted to get familiar with it forst so I'll tackle that later.
