Optical centre punch.

[Rik ShawParticipant @rikshaw]

Old eyes and shaky mits mean I am having increasing difficulty in making accurately positioned centre pops.

I have seen various types of this sort of thing being advertised and I think one of these devices might make life a bit easier.

**LINK**

I'd be especially interested in recommendations from anyone who has had the chance to compare different makes.

Rik

[Rik ShawParticipant @rikshaw]

[JasonBModerator @jasonb]

I use the Veritas one on the odd occasion when I need some accurate manual marking out, the DRO has taken over a bit now

[KWILParticipant @kwil]

Check that the target does not wander around when you turn the plastic, I have seen them where the centre wanders about, in fact I sent one back.

[The Merry MillerParticipant @themerrymiller]

Hi Rik,

I went for the "Dankroy" version not only because it was made in England but was a good online price also.

I have not compared it with any others, didn't have to as it was made in England

P.S. It also comes in a well made little hinged case.

Len.

[Gone AwayParticipant @goneaway]

I have a decent quality one of these …. best thing since sliced bread – wouldn't be without it.

I always use this like a microscope (that is, I put my eye up close to the magnifier) and it works well like that. I decided to buy a second one and chose the cheaper version that was available (not marked but likely Asian manufacture). This didn't seem to work at all.

The guy at the store said I was using it wrong, that I should stand back and look down through it from several inches or a foot away. He said that's how all these devices are used and that I was actually using even my good one incorrectly. While his method does seem to work, after a fashion, with his cheaper device, I don't find it particularly easy with either model and certainly not as good as my way with my good model. There is a much narrower field of view for one thing.

How do other people use these.

Edited By OMG on 05/03/2014 15:48:54

[Oompa LumpaParticipant @oompalumpa34302]

Hi Len, could you give me some indication of price for the Dankroy? I can't find a price anywhere online

I considered buying the Veritas offering but cannot bring myself to part with the required number of Beer Tokens.

graham.

[The Merry MillerParticipant @themerrymiller]

 

Graham,

I purchased mine, I think, off ebay a couple of years ago, I honestly can't remember the exact price. I think it may have been around £30.

Ebay have sold one recently for about £20, another went for about £40.

There has been discussions on this forum before, can I suggest you do a search, other forum members may have more pricing and location info.

Len.

P.S. if you go onto their website (link below) you can purchase direct from them, no doubt once you come down from the ceiling

 

http://www.dankroy.co.uk/ocp.htm

 

 

Edited By The Merry Miller on 05/03/2014 16:21:28

[Thor 🇳🇴Participant @thor]

Hi Rik and Graham,

why not make your own? Gadgetbuilder has a description of how to make one.

Thor

Edited By Thor on 05/03/2014 17:12:51

[Gray62Participant @gray62]

My son bought me one for my birthday a few years ago I think from axminster. I suffer from keratokonus which induces severe astigmatism. Having had one full cornea graft, my close vision is somewhat afflicted. Using one of these devices, I can pop a centre with reasonable accuracy.

[frank brownParticipant @frankbrown22225]

I have one (make unknown) which is only quite good. The real problem being illuminating the "target", as my one did not let any light to fall on the actual metal's surface.

Tip, for chain drilling, mark out on a piece of sellotape, your 1/8" drill diameter and stick in on under the lens, peel it off and move it about to get the clearance from the centre point. Now you can squint down the eyepiece and see how close to the line the hole is going to be, then use the punch. Move on to the next hole. This way you can centre dot each hole by guessemating it via the lens, the drilling then becomes easy.

Frank

[StovepipeParticipant @stovepipe]

Got mine from Chronos, quite useful. Make sure that you have decent lighting where you are using it, so you can see the place to make the punch mark. Also, like Frank said, piece of sellotape helps to keep it steady.

Dennis

[Roy MParticipant @roym]

I used this device when making air-frame jigs and lofts in the USA years ago. However, an improved method of drilling the holes is with the use of a bush bar. This is steel bar aprox 25mm x 12mm x 100mm long, a hole is Reamed in one end 12mm dia. Using the device (12mm dia),position the bush bar over the scribed lines and clamp to the work-piece. Use a drill bush to drill a pilot hole and follow up with the finished hole size using a second bush. Really accurate!

[nigel jones 5Participant @nigeljones5]

there are 4 on ebay uk at the moment

[_Paul_Participant @_paul_]

Made this a while ago works well

• Lens/viewfinder 12mm acetal rod
• Body scrapbinium
• Punch scrapbinium with a masonry nail set in the end
• O ring in base to stop slippage

Couple of hours work.

Paul

[MetalhackerParticipant @metalhacker]

The Dankroy is excellent and is easy to use for those with c**p eyesight like me. I seem to remember plans for one of these in MEW no 1 or 2 all those years ago. Have a look in the archive! The article also detailed an optical centre finder for the mill. 2 at one blow!

Andries

[Oompa LumpaParticipant @oompalumpa34302]

I am definitely going to make one, the "how to" instructions in the link above are all I needed. The material I have.

graham.

[Rik ShawParticipant @rikshaw]

Just an update. I contacted DANKROY and have just received a message from Mr Terry Wallace the proprietor telling me is now retired and no longer makes his optical centre punch.

Rik

[Neil WyattModerator @neilwyatt]

Issue one of a magazine called 'Model Engineers' Workshop' had an article on making an optical centre punch and an optical centre finder. Apparently it went on to be quite successful.

Will Doggett covered making an optical centre punch in issue 191 as well.

Sounds like a good magazine, consider taking out a subscription

Neil

[MetalhackerParticipant @metalhacker]

That sounds like an unabashed plug for the aforementioned magazine. You aren't about to become closely associated with it are you Neil?

As I mentioned above Issue 1 had it all. Picked up my first copy in a newsagent in a small town in West Australia. I have been a long way since and so has the mag. I wish you luck with it Neil and hope you can replicate the interest and diversity which enthused me all those years ago on a continent far far away!

Andries

[NobbyParticipant @nobby]

Hi
After dotting you still have to pick it up for drilling. ? in terms of a home workshop, on your mill / mill drill you could pick out the lines with a sticky pin running true. Got my flack jacket on ready for reply's
Nobby

[NJHParticipant @njh]

The thing is, Gray, you are still a young whipper snapper. The trouble with your method for us oldies is first we need to find the line to slide the punch down! ( Indeed maybe we first need to find the metal with the line on it ) I readily concede that an optical centre punch is another case of " nice to have" rather than a " must have" but it certainly does help in positioning the punch in exactly the right place. ( My punch was yet another indulgence from my wife). Like you a small tap with the optical punch is followed by a more robust indentation, with a more meaty punch, later.

Norman

[Steamer1915Participant @steamer1915]

Hello Gray,

I was shown exactly the same method by a Toolmaker more than 35 years ago. Terry is no longer with us sadly but I still use his methods.

Best regards,

Steve.

[OuBallieParticipant @ouballie]

I've used Gray's method virtually from day one, having read about it in some engineering publication, probably ME.

Couldn't believe how well it worked the first time I tried.

I'm three score and ten come September and still rely on this method, as it's quick and simple.

Talking about scribed lines, the number of models/miniatures I've seen spoiled by 'in your face' scribe lines on valve gear etc always surprises me.

Geoff – My drawer organizing marathon will go down in history as the longest such endeavor undertaken me thinks

[IanTParticipant @iant]

You are right Graham, they work much better on large flat surfaces and can 'rock' if used too near the edge of some work and they are of little use on smaller components. So I do use your 'feel' method but (like Norman) I have problems with my eyesight these days and have to use a large magnifying glass on smaller things. Strangely, even though your method is a 'touch' thing – it seems to work better for me, if I can also see what I'm doing, so I still use the magnifying glass as well.

With the Dankroy, I can use it (e.g. see well) even without my glasses provided that I have a strong light source nearby to illuminate the target (which shines down/through the Perspex rod). So I do prefer to use it where possible. It was a bit sad to hear that Dankroys are not available any more. I will have to take good care of mine. I'm always worried about scratching the Perspex at its 'cross-hair' end, there are already one or two marks.

Regards, IanT

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