Sieg C2 mini-lathe mods

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spuddevans:
I started today by reducing the brackets down to the dimensions I needed, 19mm x 15mm. I decided to leave them a little longer than the carriage width for an idea that will be explained later (or if the idea turns out to be rubbish it will be forgotten about :lol: )

Then I dismantled part of the Carriage in order to be able to measure it up. For those who may be wondering what the underside of a mini-lathe carriage looks like, wonder no more...

And before you ask, yes it did come with one cap screw missing. Setting these gibs up requires the employment of an octopus in order to loosen 3 screws while tightening 1 or 2 others. Hence the attraction to upgrade to a "single screw" operated tapered gib.

After removing the original gibs I set about measuring up to transfer the holes to the new brackets. I first up measured the diameter of a M6 capscrew, and then halved the result. Then I set my digi-vern to this value and zeroed it. Then by measuring from a datum edge (I chose the edge that would normally be closest to the headstock) to the far side of a M6 cap screw in each of the holes like thus,

And by repeating the same procedure but using the front or back edge I was able to note on the plans exactly where the centre of each mounting hole should be installed. I guess in the factory they just drill these holes without any real reference as no two holes were aligned!!

So after measuring, noting, drilling and de-burring I ended up with this.

Next up will be cutting the tapers, Thanks for watching

Tim

vtsteam:

--- Quote from: spuddevans on July 10, 2014, 01:09:05 PM ---....Next up will be cutting the tapers, Thanks for watching

--- End quote ---

:coffee: :coffee: :coffee: :coffee: :coffee: :coffee: :coffee: :coffee: :coffee: :coffee:

spuddevans:
Warning!! Epic tome ahead.

I had the day off work today, so I got to spend much more time in the workshop. :headbang: :headbang:

Before I start on cutting the tapers I wanted to cut out for the gear, as you can see it will not do as it is at the moment.

Also I tried the fit of the new gib brackets on the lathe and found that the front bracket fouls the rack by just a little.

So I took about 1.5mm off that bracket and then, after measuring the offending gear as being 17mm, I used a 16mm endmill ( the biggest I have ) and made the cutout.

And here it is in place.

Now that's done it was on to cutting the tapers. In Bog's thread about Darren's lathe he temporarily glued a 1.5mm pin on one edge to set the taper, and I was going to do the same when I discovered I didn't have any superglue. So I came up with an alternative version, and verified it using my little digi-angle-finder. I used a 1.3mm drill bit to space one end ( circled in red )

Then I rough milled it with a 3/8" roughing endmill and then finished it with a 10mm carbide cutter. Then I did the same on the other bracket, remembering to get the taper going the right way.

I was hoping to mill up the gibs themselves, but when I looked through my stash-of-scrap I didn't have any suitable pieces of brass. ( I did have some that was way too big, but the price of brass is too much to mill that much into swarf )

So instead I decided to press on with another little mod, the cover for the handwheel gears on the carriage. As supplied, it looks like this.

I was going to get all technical and start measuring up and marking datums, but then I realised that I could do it much simpler. I measured the shaft to be 17mm and, after cutting out a suitable piece of 1.5mm ali sheet, I bored a 17mm hole in what seemed to be roughly the right place. Then I had to file a little radius on one corner (red circle) so that I am able to manipulate it in and one edge fits nicely under the half-nuts.

Then, while holding the ali in place, I traced out the outline of the casting with a pencil. (actually I had to do this twice as I smudged it the 1st time )

Then I rough cut it on the bandsaw, remounted it on the casting and held it in the vice and carelessly filed it to shape, and then drilled the cover for mounting screws (and gently marked the casting too)

Then it was over to the mill to align by eye and then drill 2.5mm. I was only able to get one clamp on it so I took it really gentle when drilling. ( this casting drills and taps like a dream )

I seem to remember seeing someone else doing a similar mod and they found that the gears sit a tiny bit proud, and their solution was to mill a recess in the cover to prevent the gears from binding. My lazy streak kicked in and I thought I could make it a little simpler. Both gears have shoulders to space them out from the casting, and I measured the shoulders at just over 1mm.

Now if only I had a working lathe !!! But I do have a vertical lathe, of sorts.

As you saw, I even aligned the tool with the very same ruler I use to set the toolheight on my lathe. Actually I had to do this twice as the above tool was the wrong geometry.

It worked just fine, all I needed to take off was 0.25mm from each gear's shoulder.

Then after tapping the m3 holes in the casting I was able to mount the cover.

This what it looks like in situ

Sadly the brass I've ordered for the gibs wont be here until at least tuesday, so I will have to think up some other mods to be getting on with in the meantime.

Tune in next week to see what happens.

Tim

spuddevans:
After some thought as to what "mod" to start on next (while I await delivery of brass) I started today by cutting a chunk-o-rust off in the bandsaw (thank goodness for bandsaws, I would really hate to cut this 63mm steel bar with a hacksaw)

I then popped it in the vice and used another offcut to make up for any unevenness/out-of-square-ness, and picked a roughing cutter. I'm now using the Ball-raced ER32 nut and I have to say that I am a convert. My collets are metric, and I used to have to juggle with trying to hold the cutter in place (it is 3/8" and the collet is 10mm) and keeping the spindle "lock" button held in while trying to tighten up the ER32 nut with a collet spanner. Now I can close up the collet nut just by hand until it grips, then finish off with a little tweak with the spanner. Well worth getting, I will be getting another one for my lathe.

After a short while I had somewhat distributed part of the steel all over the place

I need to rig up some swarf barriers

Anyway, after a little while and lot of swarf I ended up with this. Anyone guess what it is?

Maybe this will give you a clue.

A new foot for the tailstock, I'll show you a pic of the old and new together a bit further on. My dilemma was how to accurately position the hole for the clamping screw. The hole in the tailstock casting is about 12.7mm, so I routed in my scrap-box and found this

So I chopped the end off that was threaded, inserted a sharpened grub screw into it thus,

With the new "foot" in place I used my very expensive marking system to blue (black) it up. and popped the sharpened grub screw holder in place.

Worked pretty good eh?

Then by measuring from the end of the casting to the point of the grub screw and transferred that to the new foot. Then drilled 10mm through, and counterbored from the underside to give room for a nut and big enough for a socket to fit over it too. (although I'm toying with tapping it M12 and doing away with the nut altogether)

And here is the promised pic comparing old and new.

I also re-installed the lathe's original gibs and re-assembled the carriage, as the next parts of the cam-lock need to be turned.

Thanks for watching,

Tim

vtsteam:
A custom transfer punch! Or transfer scriber, properly.
Worked well! :thumbup:

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