Centering the Unimat SL 1000 lathe

[@fw1421]

I picked up a Unimat Lathe like this back in the 80’s at a flea market in practically unused condition fort $200. What a steal.

[@Smallathe]

Congrats!!! That is a steal and wonderful! You will love it! I'd warn you it's so much fun it's addictive - but you already got hooked ;)

[@machinistmikethetinkerer4827]

hi Saar-thanks for the refresher and yes I watch Mr. Pete's videos too. we finally got off the road in our RV and into our new home so I'll be setting up my new watch shop including my Unimat workbench, soon. I think my next video will be on the Unimat dividing/indexing head.

[@Smallathe]

Sounds great. I was thinking of making one myself... Looking forward for your next video!

[@TheKnacklersWorkshop]

Hello Saar, Nicely explained... Take care Paul,,

[@Smallathe]

Thanks Paul. Much appreciated.

[@Slemi]

I have some old booklet where it says you just take booth of the centers and put them inside headstock and tailstock. You remove that big spring at the back of the lathe and push the headstock forward as much as it goes. Next you move tailstock towards headstock until points meet and eyeball the aligntment. I found this to be accurate enough. I use some lupe to magnify points as my eyes are not what they used to be.

[@Smallathe]

Yes,that will work ok. There are lathe centering buttons that use the same principle too. But I think the long bar gives me a much better accuracy over a fairly long distance. Slow, but accurate.

[@paultrimble9390]

Hello, that will work for me to. I was thinking getting another head stock and fix it up in the back middle. So always have mill. But in till then use that way. Arrow would work in pinch long as not bent.

[@roadshowautosports]

I understand this video is 3 yo but will take a shot: I noticed you were licking your head on the back of it, and not using the lock pin on the side, could you describe how you do that or show it in pictures/video? Great video, with all of the reality that is to move the table from one side to another!!! It’s really a pain. They came with the thread attachments that could do such thing but they are super expensive nowadays. Thank you for your videos and clear explanation of what you’re doing!

[@Smallathe]

Hi Mate. Good question. The lock pin is more of a safety feature, It doesn't really give you precision centering of the head. So I center the lathe and then plae the locking pin in. The head of the lathe - if I understand your question - pivots on a hinge - a center pin. The idea is you can turn the head of the lathe, turn your work at the desired angle and then center it again. This is very annoying if you need to make several angles and to turn straight shafts between... which is why I eventually made my own unimate compound rest. :) Hope my explanation helped

[@dannyakatrikerred7381]

Hello Saar. I'm thinking that a small DC motor with a rheostat to control speed and a reversing switch to power the feed. Could be driven by an O ring to a narrow sheave mounted behind the hand wheel. O ring could be easily removed for manual function. 🤷🏼‍♂️. 🇺🇸😎

[@Smallathe]

Agreed Danny!!! I actually harvested such a motor from a broken toy. It's on my "to do" list.... It's just a long list!!!

[@paultrimble9390]

From a train 🚂 set.

[@Smallathe]

@@paultrimble9390 yep. Or RC toy car...

[@juanzuluaga3388]

The procedure tests for the line between the pointy ends of the dead centers to be parallel to the rails: it does not test for the spindle axis to be parallel to the rails. Am I missing something?

[@Smallathe]

Hi. Yes, you are right, but any steel will bow in the middle (and I lack a carbide rod to that end. So I am actually looking at the gauge only when I'm very close to the ends. You can measure the centers themselves but I prefer it this way. larger lathes have a measuring rod with precision ends. - this is a similar concept. I'm using a stainless steel rod that has nicely centered ends to do the same thing. Tubalcain showed several centering methods - do check his videos. I plan on doing those again too.... if time allows...

[@davidk5677]

Do you no we're I would be able to get the harding steal center from. I have one of them that came with this lathe but not two?

[@Smallathe]

Hi David. Do you mean the lathe ways? You can buy these from ebay. Just search "unimat SL DB ways". Here is one of the ways offered for sale there. www.ebay.com/itm/143833727174?hash=item217d2880c6:g:TYkAAOSwUm5fqmFo Alternatively, you can buy hardened, precision ground 12mm steel rods and cut and drill them to fit the unimat dimensions, but that's a lot of work.

[@roadshowautosports]

@@Smallathethe only advantage over the amount of work is the certainty on how precise it can be. Most on eBay are old and worn so caution is advised.

[@Smallathe]

True!@@roadshowautosports

[@clawsoon]

Useful video, thanks. It seems like you could align quicker and maybe save yourself a back-and-forth or two with a quick calculation. Let's say it's 80mm from where your indicator starts to where it stops, and your indicator shows a 200 micron change in that distance. That means your slope is 200/80 = 2.5 microns per mm. The offset you're missing is the distance from the tip of the tail to your indicator start position. Let's say that's 20mm. 20mm * 2.5 microns per mm = 50 microns. So if you change your initial adjustment to 200 microns + 50 microns = 250 microns, you'll be a lot closer the first time. You'll notice that you can make the math a little simpler: - distance from the tip of your tail to the indicator start position (20mm in the example) - divided by the distance the indicator travels (80mm in the example) - equals 1/4 (for this example). So the tweak you need to make to the adjustment is 1/4 times the indicator change. 1/4 times 200 microns = 50 microns, so use a total initial adjustment of 250 microns. Same as the first result, just a little easier to understand the steps. This would make more sense if I could explain it with a picture, lol.

[@Smallathe]

Neat idea! Thank you! I didn't think of it this way - but you are right. I'll try it next time. I did try over setting to compensate but didn't try to calculate the offset - and I will install a motor to speed things up.

[@clawsoon]

@@Smallathe Let me know if it actually works. Sometimes this kind of thing works a lot better in theory than in practise!

[@Smallathe]

@@clawsoon will do! If the math works out I'll make a video on this method with due credit :)

[@clawsoon]

@@Smallathe Great! It'd be great to see you draw a diagram explaining it in the video, if that's doable.

[@TadeuszTarka-so2dt]

Czy na Unimat 3 też tak można regulować?

[@Smallathe]

English please?

[@TadeuszTarka-so2dt]

​@@Smallathe Is this also possible with Unimat 3?

[@Smallathe]

@@TadeuszTarka-so2dt I think so. It needs to be adapted to the machine specific design. Try! :)