Just wondering if anyone has converted their cross slide dial into metric. I am going to make a zero adjustable dial that I saw somewhere, and while I'm at it, I am going to make a new dial with a metric scale on it. If anyone hasn't done it, maybe you could throw me a few suggestions on the best way I would go about scaling the dial. I haven't actually made the dial part yet in the lathe, so I can make it slightly bigger or smaller than the imperial one that comes as standard. My main concern is getting the diameter right for the dial so I have an exact amount of graduations. eg. 1 full revolution is equal to 1mm or 1.5mm etc. Just can't get my head around it

Dave, it doesn't matter what the diameter of the dial is, except to make it large enough to easily read your graduations. You can put the same amount of graduations on a dial that is one inch diameter or 10 inches diameter. 360 degrees is 360 degrees.

What actually makes the graduations meaningful is the pitch on the lead screw, and it will dictate how many grads to use for even spacing. If you want to go metric, you need a metric lead screw to do it right. For instance, a screw with a 1mm pitch will let you have a dial with 100 grads, giving .01mm per grad.

If you use a lead screw of .5mm pitch, you can use the stock Taig dial, and it will read in 50 grads of .01mm instead of 50 grads of .001 inch.

Using the stock dial and changing the screw would only involve making a new lead screw nut, and buying a metric lead screw to match. Remember, they are LEFT hand thread!

Trying to make a hand wheel that reads metric while your lead screw is imperial is a messy business. The stock Taig cross slide lead screw is 20 tpi, or in other words, a pitch of 1.27mm. Try to divide that evenly by any number of dial graduations you care to, and you will see the problem of mixing the two systems for this project. You are always going to have a partial increment left over for any usable graduation you choose for your hand wheel.

See if you can find a 6mm x .5 pitch left hand thread rod, and make up a new cross slide nut for it. Turn the end of the threaded rod down to match the stock Taig lead screw, cut it to length, and you will be set to use the standard Taig dial.

Dean

Ah, that makes sense alright. Not what I wanted to hear though I didn't bank on getting a new leadscrew. I wasn't thinking of the thread on the leadscrew. Of course it's in 'threads per INCH' - which is what was messing me up. Ideally (like you said) 1 360 degree turn of the leadscrew should be 0.5mm or 1mm etc. I will try and source a leadscrew locally, but am doubtful if I will suceed. It's not a major problem though. I don't mind stiicking with imperial if it comes down to it. Thanks Dean for clearing that up for me.

Hi Dave;
If there is a Sherline distributor in the UK you may be closer to that lead screw than you think. Sherline uses a 1mm pitch left hand thread lead screw for their metric version of their lathe. You may just be able to order a replacement metric lead screw from Sherline to adapt to the Taig.
You'll also need to find a matching LH tap for the same thread to make the new lead screw nut.

I don't know how things are, supply wise, where you are located, but I would think something like m6x1 threaded rod would be common, and LH rod should be available "somewhere" in England, if not Ireland. That's how I get uncommon things like this in the U.S. Supply houses generally carry a lot of LH pitch rod that is not available at the hardware store.

Good luck with your project.

Dean

Good thinking. I didn't think about Sherline at all. I didn't see a leadscrew part being sold seperately on their site, so I sent off an email to them.

I have also searched the usual suspects over here, and it seems they all only sell right hand threaded rod. I have sent a good few emails to them 'just in case'.

Next step would be to buy a LH die myself and get a length of rod and make one. I have sourced a place that have LH taps and dies.

I will wait a few days for some emails to come back and take it from there.

Actually Dean, just looking at your website...did you ever get around to the gears for threading on your lathe using the 'other' leadscrew that you put on your lathe? The reason I ask is that if I buy a long threaded rod, I will use some of the rod and modify the lathe with a similar design as yours. I would like it to eventually have threading capability though.

No, I haven't got around to it yet, Dave. I have a long, long list of machine and machining related projects. The items on the list get added faster than I can cross them off, and the screw cutting gears are down the list a ways, since I have another small lathe that will cut threads. They are still on "the list", but I have clock, engine, camera, and other tooling projects ahead of them. Time is my only enemy!

Dean

I have ordered some Sherline leadscrews from the UK (cross slide and one parallel to the rack). Although it looks like there might be a postal strike going on in the UK, so it might be a while before I get anything. It is also a bank holiday on Monday here, so I guess I couldn't have chosen a worse time to place an order. Oh well, I have many things to keep me occupied anyway. I know exactly what you mean by "the list". Mine too is growing faster than I can manage. I see too many great projects on the web!!! Also, while I'm working on a project, I see ways of modifying parts on the lathe or mill that would make life easier.