After buying a DRO unit to replace one that came originally with my lathe some 5 years ago I had some issues getting it to work.

First of all I was buying one from Singapore that advertised it as “Suitable for replacing your faulty scale / using other brand of linear scale/encoder feedback.”

I must admit I was more than a little skeptical but checking their feedback reassured me that they seemed a genuine company. Also the cost, even including shipping from Singapore to the UK for a total of approximately £120 ($200) was £60 cheaper than the original supplier (China) quoted. I decided to go for the cheaper option (twas every thus!).

Whether the aggravation was worth it then I suppose it depends on where you are in the process... When pulling my hair out over the last few days trying to get it to work, then I cursed myself for being a cheapskate (or poor....). Now that it is finally working, I have a bargain!

The positives and negatives of the project from my perspective.

Communications:

Both negative and positive! Peter, the chap I was emailing, always answered emails promptly. However language proved difficult for me even though we kept sending photo’s. If I followed what I thought (not necessarily what Peter meant!) it wouldn’t work. Resulting in several photo’s/diagrams being emailed between us. One major issue revolved around the numbering of pins on the D plug. I was reading the numbers relating to pins to be soldered to the pins to be soldered!!!! No, the pin numbering relates to the front of the plug! Indeed the numbers could be seen when using a Jewelers loupe. I then constructed my own diagram and worked out the colours for each pin from Peters labeling of a photo I sent him showing existing wiring (this was the cause of the breakthrough really). One further fault/frustration was by reading that one pin needed to be soldered and then earthed (or so I think) and when trying the plug the numerals would only change up/down by one digit increase/decrease. In frustration I decided it looked like an earth fault (don’t ask me why!) and I thought &^%$$% it, I’ll cut this earth wire to that pin.

Low and behold, when connecting the plug up it worked!!!!! The second plug was then wired and I had two readings...joy oh what joy. Then I thought that knowing my luck there would be something wrong with the accuracy of each axis. So I set up a dial indicator and checked the readout movement against the dial indicators and all was well, phew! There was a slight difference but I wonder whether in fact this error is in the dial indicator or not...I suspect it is.

So if you do buy one of these DRO’s and you have the same make of scales (see picture) then the methodology highlighted below worked for me.

One major misunderstanding related to the numbering of 9 pin D-sub miniature plugs. The pin numbers relate to the front of the plug whilst you solder to the back! Now I consider that DAFT!

Using a jeweler loupe I saw the numbers on the front side of the plug, then transferred this to a diagram of my own identifying the pins from the rear and allocated the colours to that diagram. I then de-soldered all the wires, so having a clean starting point.

Solution

Remove all wires from D plug and identify the pin numbers (look at the front of the plug). Make your own diagram showing back solder part of pins

• Solder yellow wire to                 pin 9
• Solder Green wire to                  pin 8
• Solder Red  wire to                     pin 7
• Solder Blue wire to                     pin 6
• Solder Black wire to                   pin 2   (you can just leave this one in place if you wish since it doesn’t move)
• Solder back the Earth cable to the body of the plug

This results in a working solution that was not easily seen from Peters diagrams and photo’s but that may be as much to do with me not understanding enough, so I won’t lay all the blame on Peter. If you know more about electronics you may have had no problems!

I have added various photo’s of the steps I took to perhaps help.....If I had the above simple instructions from the start, no doubt it would have gone easily...To be fair to Peter he has asked for this solution so he can add it to his blog for assistance to others.

I have no complaints (now!) with the unit itself. It is far more substantial than the original Bica unit and I would suggest its more the top end of the market, so price seem very reasonable.

Would I do it again? You bet! Would I have done it again yesterday afternoon? No way! So what a difference 24 hours makes.

In summary the unit was certainly not plug ‘n’ play for my make of scales but Peter did help to get it working and that’s fair enough for me. I believe that Peter’s company will supply complete sets with scales and of course that would be a simple fit, and I have promised to fit a set to my refurbished Myford at some time.....but the purse is empty this year so it will have to wait

For some time I have been wanting to add video's to help novice model engineers in subjects I wished I had some help in myself. The first video is on how to centre a bar when turning it on a lathe using a 4 jaw chuck. Future videos will cover other basic skills such as tapping, threading and screw cutting, rotary table work, basic milling skills and others that may be asked for. So if you are a novice engineer and want help on a particular subject just drop me an email and I will make one or brig it forward if it is already on the list.

All the video's will be hosted on you tube and listed on my main website (having trouble uploading updates at the moment so please bear with me.

Turning my workshop into a video studio!

To see the video itself click on the link  How to centre a bar in a 4 Jaw chuck

I am going to add a series of 'how too' posts to my main website as well as this blog. These are aimed at the absolute beginner or novice and are at the basic level. If you have any 'requests' for a topic then either email me or leave a comment on this blog.

The first in this series is how to remove a broken stud or thread. The example used is a handle that snapped off on my lathe. The part is a closed nut and handle that is used to tighten down on the toolpost. The first task is to carefully drill a pilot hole into the broken part. I aways use a cutting oil to make sure the drill keeps cool and use a good sharp drill.

I used a centre drill followed by two drills, increasing the size of each. Once the hole has been drilled the correct size stud extractor was inserted into the drilled hole and steady pressure applied in the anticlockwise direction. The stud extractor works by tightening itself as you screw it in, and then the force applied goes into moving the remaining thread.

If your careful and make sure your pilot hole and then further drilling is central, then it is very rare that this method fails. It never has for me ............................Below is a set of stud extractors and they can be found relatively cheaply on eBay.

DRAPER 55641 STUD EXTRACTOR SET 1 2 4 PIECE    £23.50

SCREW STUD EXTRACTOR SET 5 PIECE SET 3mm to 18mm G5    £6.99

Vintage Herbrand Automotive Stud extractor    £15.04