Sieg C2 mini-lathe mods

[vtsteam]

I've been wanting to get rid of the need for a tailstock wrench on my lathe for some time. 

[spuddevans]

Thanks Kjelle, David and Steve 

Finally I have completed one of the Mini-Lathe mods - the Tailstock Cam Lock.

I didn't have much left to do from yesterday. I started by marking up exactly where I wanted the little lock/release lever to be, then it was mounted in the Stevenson's ER32 block in the vice, and indicated the centre.




I know I've mentioned it before, but someone had asked me just how good the Ball-raced ER32 nut's are. I had to drill a 4.2mm hole for tapping M5, so I used a 5mm ER32 collet. Previously I would had to have used a C-spanner to close the collet enough to grip the drill, but with the ball-race-nut I was able to close it up with just my hand.


And I am also loving the Stevenson ER32 blocks, so easy for gripping round stock in the machine vice, and now I used it to make sure the shaft was kept square for tapping.




Then I parted off the cam to length. Then I threaded a short section of 5mm steel for the handle, assembled everything and then marked where to cut the handle, and then cut it and rounded the end off.

Here's all the componant parts. The cam has about 1.8mm of "lift" (or to be technically correct, "drop").




Then I started assembling. I used a couple of E-clips to stop the Cam from moving about, the back one requires turning the block 90degrees to fit.




Then the foot was screwed on, and after checking it was screwed in enough (and not too far) a locknut was tightened.




Here's it in "Unlocked"




and Locked




As you can see, there's not much in it, and it really locks solid with very little pressure.

I totally recommend doing this mod, it is so much better than the original method.


The brass needed for the tapered gibs arrived today, so after finishing up the Tailstock cam lock I disassembled the lathe's carriage. Then I mounted the new gib brackets on and placed it back on the ways. I was wanting to check if, and how much, clearance there would be between the brackets and the bed casting.




Looks like there's about 0.75-1mm of clearance at the front, and there's about the same on the back. So the plan is to mill the gibs down to about 0.25-0.5mm wider than the brackets. Because the front and back brackets have different depths, I marked up both ends of each gib to indicate which belongs to which.




Then I milled each Gib down to their respective widths, then, using a little round-over bit, I eased the 2 corners.




This was so that they wouldn't foul in the sharp corner of the bracket




And that was all I could get done as I had to go and make some nourishment.

Next up will be milling the tapers on the gibs.

Thanks for watching.
Tim

[Brass_Machine]

Hi Tim,

You are making some headway. A lot more than what I am doing on my lathe that's for sure!

So I went back and started reading from the beginning again. It looks like both the gib and the bracket are tapered?

Eric

[spuddevans]

Thanks Eric, I'm trying to get as much done as possible as in a week's time I will be unable to get into the workshop for about a fortnight.

It looks like both the gib and the bracket are tapered?

Yes that's right. In order to present a parallel bearing surface, both the bracket and the gib need corresponding tapers. Then a horizontal movement of the gib makes a vertical movement to tighten up against the ways.

Tim

[spuddevans]

So on with the tapers. I was going to leave the brass gibs un-tapered, but then figured that they would only give the same amount of grip as the factory originals.




So over to the mill and used the bracket to hold the gib for machining the taper, this ensures that the tapers will match each other perfectly.




I took off just the bare minimum to cut the taper, and then I couldn't help myself and just had to try it on the carriage. Still needs more taken off




I took it easy with the cuts, taking the time to check each time to make sure I didn't go too far. Each time I fitted it together I would score a pencil line where the edge of the bracket was




Next was drilling for the adjustment screw in the brackets. As the screw heads are 11mm diameter I decided to space them in from the ways by 6mm. I marked up the end of the bracket and put it in the vice. To get it vertical I used bog's trick of using a engineers square on the mill's bed and shining a light on the back of it. Shows up exactly when it's square.




Then to tap it M4 I clamped my tapping stand onto the mill and swivelled the head over. Worked a treat and made sure that there was no lateral flex on the taps.




In order to stop these brass gibs from moving out of place I want to put a couple of pins in each bracket and a corresponding groove in both gibs. I started off by measuring from the side of the gib that faces the bracket.




Then milled a 2mm groove in the centre of the gib




Then I poked a couple of 2mm holes in the bracket




Then a couple of short 2mm pieces were loctited in the holes




Then  it was on to the little groove that the adjustment screw fits into. I milled out a groove with a 3mm endmill, the screw head is 4mm thick, so I milled it to 3.8mm and then filed it to fit




It works!!




And it is about 1mm shy of the other end




Both done




Can I say smooth!!! It is like silk, and got better after a little oil ( always helps )

So another mod gets ticked off the list

Next up ...... I'm not sure. I'll see how the spirit moves me when next in the workshop.

Tim

[Chuck in E. TN]

Well done, Tim!
I am collecting the material to do the same to my 7x14. But, you made it look easy!
Chuck

[vtsteam]

Great job! Well photgraphed, too! 

[S. Heslop]

Fantastic work. Yeah those photos are brilliant. I guess you must have alot of light in your workshop! I need to add way more light to mine but I think i'd have to replace all the existing wires.

It's doubly nice to see photos of these mods too since I was disappointed that the photos from bog's thread all disappeared. I might even save the thread to my hard disc when it's complete!

[spuddevans]

Thanks guys, I'm glad you're enjoying it

Fantastic work. Yeah those photos are brilliant. I guess you must have alot of light in your workshop! I need to add way more light to mine but I think i'd have to replace all the existing wires.

About 3ft above my mill and lathe I have 2 double and one single 4ft fluorescent fittings end to end, then on the other side of the workshop I have 3 single 4ft flourescent's end to end (the 2 rows of fittings are about 4ft apart. They were all reclaimed fittings, a few of them I replaced the ballast with electronic ballast to fix them, got them off ebay for a few pound each.

All that being said, the photos were all taken with flash, so that's why the workshop looks so bright.

It's doubly nice to see photos of these mods too since I was disappointed that the photos from bog's thread all disappeared. I might even save the thread to my hard disc when it's complete!

When I'm finished with the mini-lathe mods I probably will make a PDF of it all, but organised a bit better.

Tim

[spuddevans]

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

[micktoon]

Nice mods there Tim and well shown , should make your lathe nicer to use 

  Cheers Mick.

[Chuck in E. TN]

Tim, love the knurled screws for the change gears. I modified the B/C stud setup on the standard banjo to eliminate the nut behind it.  I reversed the slot nut and the whole stud is accessable from the outside. I also made a dedicated fine feed banjo using 80T Mod1 gears salvaged from a lazerjet printer.
Chuck

[spuddevans]

Thanks Mick  even though I have plenty more mods planned for it, the improvement with just the tapered gibs is unbelievable!

I modified the B/C stud setup on the standard banjo to eliminate the nut behind it.  I reversed the slot nut and the whole stud is accessable from the outside.

Thanks Chuck, do you happen to have a pic or 2 (or could you take some) of that mod, I'd love to make the adjusting of the banjo easier, but I can't quite picture what you've done

I too want to make an extra-fine feed, I haven't decided whether I will go for a mechanical, ie geared, approach or to go for a separate motorised feed.


Tim

[Stilldrillin]

Very well done, and shown, Tim! 

My gib/ retainer mod, is still doing the business. Never having been adjusted, since installation...... 

Now you've a working lathe again.
Make a metal spacer. To replace the plastic one, between the spindle adjusting nuts, and rear bearing. Even if you don't intend to fit taper bearings......

David D

[Chuck in E. TN]

Thanks Chuck, do you happen to have a pic or 2 (or could you take some) of that mod, I'd love to make the adjusting of the banjo easier, but I can't quite picture what you've done

Tim

I took the origional banjo apart and reversed the setup on the slot nut for the B/C stud. I can setup the B/C gears and tighten the stud finger tight to set gear spacing using a piece of phonebook paper, then tighten the stud from the outside. I used a piece of 10mm hex stock salvaged from a paper shredder to make the nut and inner shaft. A sleeve bored to slide over the 10 mm shaft is drilled on the other end for the M6 nut/screw.
The picture with the origional banjo shows the origional B/C stud setuo on the left, the new on on the top right.
For the fine feed banjo, I set up the fine feed on the origional banjo and coppied the positions of the gear studs to a piece of 1/4" plastic. The gears shown with the Fine Feed Banjo are 80 and 20 tooth, salvaged from a laser printer.I set them up on a bush and epoxied them together.
Pics here:
http://s571.photobucket.com/user/chucketn/library/Lathe%20Banjo%20mods
I think I made a dimentioned drawing of the FF banjo layout, if not, I can trace it and post the tracing.
Chuck
Chuck

[spuddevans]

Now you've a working lathe again.
Make a metal spacer. To replace the plastic one, between the spindle adjusting nuts, and rear bearing. Even if you don't intend to fit taper bearings......

I intend to do just that, and I am leaning strongly towards the Taper Bearings. Do you know if there are any spacers in the headstock? and if so what width they are? (may as well make all the spacers at the same time, assuming they are all the same I/D)


Thanks for those pics Chuck , that's given me something to think about.


Tim

[Stilldrillin]

Spacers Tim?    I dunno! 

I left the headstock in place. Slid the spindle out, through the gears. Swapped the bearings. Greased up, and rebuilt.

That was 5 years ago...... 

(I did have a bit of locknut trouble)...... http://madmodder.net/index.php?topic=1292.0

David D

[John Rudd]

There are two spacers.....plastic....
How on earth do you set bearing preload with plastic spacers

See my thread on the mini lathe bearing change.....can't find the topic atm....