Author Topic: Sieg C2 mini-lathe mods  (Read 16688 times)

Offline spuddevans

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Re: Sieg C2 mini-lathe mods
« Reply #30 on: July 19, 2014, 06:55:42 PM »
Thanks Hugh, it sounds like a worthwhile mod  :ThumbsUp:

Graham Meek had warned me that the milling on the underneath of the ways does not extend that far in, and to watch out for the gibs being too wide as they would jam up on the un-machined casting. He was dead right, I had left about 1.5mm gap on the back gib and about 0.75-1mm on the front gib, but noticed that when the gibs were snugged up with the carriage at the tailstock end, the carriage would jam up when about 4" from the headstock.

So I loosened the gibs enough to be able to smoothly push the carriage the full length of the bed, then put a light behind it and took a pic of the back gib




See how the rough casting has pushed the gib away. So I removed the gib and milled a little off just that corner (about 0.75mm wide by 0.5mm deep) Then replaced it and took another pic.




That's better, I am now able to snug up the rear gib and it runs smoothly the whole length. I also discovered that the front gib had the same problem, so I did the same for it and took 0.5mm x 0.5mm edge off the length that faces the casting.

If I was doing it again I would make sure there was at least 2mm gap between the casting and the gibs.


Another little issue that reared it's head in this mod is a little interference




The top half-nut catches on one of the cap screws holding the gib bracket on the carriage.

A simple solution was to thin the cap screw, which was a simple turning job.




Compared with a normal cap screw




That did the trick, the half-nut clears the new cap-screw.

I had considered adding a couple of "counter" screws to the other end of the gibs to lock the gibs, and I may well install one on the front gib. But if I put one on the rear I will lose about 1" of travel at the headstock end (it butts up to the backsplash) and if I am using a faceplate I may not be able to get close enough to it.

I think I may have another solution though, I'll let you all know when/if it works.


Anyway, on to the next mod.


I chucked up a 20mm steel bar




and turned down a 14mm section and then a 6mm section




I was amazed at how well the lathe cut with the new gibs, I was easily able to take a full 1mm deep cut per pass (2mm off the diameter)

Then I die-cut M6 thread and knurled a section.




Then it was cut off in the bandsaw and I repeated the process a couple more times. Then I reversed them and faced the cut end on all 3, and also cut a shallow groove (just enough to remove the knurl) on one (the one that was threaded M5)




And this is what they were all for




That should make changing the gear train a little easier, save having to dig out 2 different allen keys.


That's all for now, and sadly for the next couple of weeks I don't expect to get back into the workshop due to real life getting in the road of hobby-time.

Annoyingly my camera lens has started to fail, doing a google on the symptoms shows that it is a common enough problem, but at least there is a few "How-to" tutorials on fixing it (once the replacement part gets here from china). So hopefully that will arrive when I can get back into the workshop, then the camera can be the next mod!!

Thanks for watching,
Tim
Measure with a Micrometer, mark with chalk, cut with an axe. MI0TME

Offline Graham Meek

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Re: Sieg C2 mini-lathe mods
« Reply #31 on: July 19, 2014, 07:31:07 PM »
Hi Tim,

Glad I could be of help, these machines with a little TLC can be very good machines. Sometime back I added a screwcutting clutch to my friends Warco lathe, there are a couple of photographs below. The threading action makes machining threads on these lathes a walk in the park.

My best regards
Gray,

Offline spuddevans

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Re: Sieg C2 mini-lathe mods
« Reply #32 on: July 19, 2014, 08:17:20 PM »
Glad I could be of help, these machines with a little TLC can be very good machines. Sometime back I added a screwcutting clutch to my friends Warco lathe, there are a couple of photographs below. The threading action makes machining threads on these lathes a walk in the park.

Thanks Gray, even just doing the gibs has improved it beyond belief.  That looks an interesting mod for screwcutting. I want to make a "Swing-up" threading toolholder to make threading easier, but the clutch looks good too.  :ThumbsUp:


Tim
Measure with a Micrometer, mark with chalk, cut with an axe. MI0TME