Sieg C2 mini-lathe mods

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

spuddevans:
Thanks Kjelle, David and Steve :thumbup: :thumbup:

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.

--- Quote from: Brass_Machine on July 15, 2014, 05:57:46 PM --- It looks like both the gib and the bracket are tapered?

--- End quote ---

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

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