Gallery, Projects and General > Project Logs

C3 Upgrade and improvement - I hope

<< < (3/5) > >>

PeterE: Thanks for very good suggestions! Eric; the way to get hardened tips using ball bearing balls is really good! The set screws are M3 So I need balls somewhere around 2 mm dia which should not be a problem. Andy; I read through the setting of the saddle "gibs" as described in MEW at the time and have also read some other versions in other places. I then find that the gib strips for the saddle (whatever they are called) should really be well secured against the saddle to avoid loosening from vibration. To set the play using the set screws and the securing screws will most probably be even fiddlier than cutting a few strips of alu cans or trays (how could I forget having read about that as well?). Loply; Thanks for sharing your experience  :thumbup: I will certainly think of that! As far as I ahve come right now, I found that if I nipped up the saddle gibs finger-tight (without using the jacking set screws) I could move the saddle all the way from head-stock to tail-stock without it nipping anywhere. Hmmm, this means that each machine is individual, and mine seems to be parallell then. So far I have flattened the saddle gibs using a fine file which made the saddle move smoother than before, interesting ...  To avoid filing where I don´t have to, I made guides from a nut using the corner as tip ... ... and supported a file with a safe edge against the nuts. Thus I could gently file the surface smooth. Work (and experimenting) continues ... /Peter

bp: Hi Peter, Bogstandard did pretty much the definitive mini lathe refurbishment/improvement thread on this site.  It includes tapered Saddle gibs....the Rolls Royce way to go.  Do a search for "Fixing Darren's Lathe" or something like that. enjoy. I recently did the George Thomas suggested "Gib Dowel with lockscrew" mod on the compound and cross slides of my mini lathe and can highly recommend it Bill

PeterE: Hi Bill, Thanks for pointing me to that I will go through the thread thoroly before  going further. Some work done today. I took my time and did the gib strips for the saddle. After some measuring and testing I found that it would work well using shims and to tighten the gib strips hard against the saddle as shown below. The picture taken when everything was assembled for the last fitting. The socket head screws are replaced by Loctited studs. The small jacking screws are still on the gib strips but are not used. Not needed anymore so I simply left them where they were. Interestingly I found that when adding the same shim thickness over the whole width of the saddle it rocked sligtly at hte headstock end. Same on both front and back. Had to cut the shim on that end to get rid of the play and now the saddle slides easily over the whole bed length without any play nice and sweet. Turning the saddle over I noted a couple of things that may be of interest. The C3 (SIEG) saddle is not "whole" on the tail stock side which is a pity. If the middle piece had been there it would have been much easier to add a saddle lock. Now I have two small pegs onto which I hand the said lock when needed, but this in turn limits the possibilities to add saddle lubrication points of the same type as the Real Bull or WEISS version(-s). Not even the cover screws for the travelling steady are placed to double as lubrication points unfortunately. It would be possible to place a lubrication point at the left back end of the saddle right in front of the strady scrwe and then allow for a small "canal" for the oil to travel the whole width of the back part of the saddle. Well, at this point I will consider the saddle to be done and continuing with the apron. The gears fixed before work nice and sweet without play - good meshing actually - and the gear mesh well with the rack on the bed as well. The work done today was to improve the dimples for the half nut gib strip = done. Worked nice even using a hand drill. The washers were replaced by a longer keep plate but I maintained the two screws holding it. Finally I added the securing pin to avoid the gib strip to fall out if become loose again. The pin is 2 mm and made from a broken 2 mm drill bit. You can see the small hole at the far right. The set screws will get a ball bearing ball as suggested when the balls arrive. Good tip!  :thumbup: Work slowly continues ... BR /Peter

PeterE: So another days work and the lathe is slowly being re-assembled. Re-checked the saddle this morning and thought is was done. Lightly moving all the bed back and forth. So mounted the X-slide and topslide back on as I had to use the machine to make some small adjustments to the new hand wheel for the saddle. The old plastic one had given up. In the following picture the apron is also back on but only lightly fitted as work is ongoing to adjust the leadscrew and its new right-hand end bearing setup. The new hand wheel has a slightly smaller diameter (80 mm) which actually is good as the distance between the cross-slide ball-handle and the saddle hand-wheel is a bit bigger. Due to this my fingers can now pass between the handles without disturbing any settings. The new hand-wheel also have a scale ring (still not graduated though) that can be set as required. Also the lead screw is back in place with its new right hand end bearing. My solution for this is done using the solution from the Tools and Mods site but adapted to a SIEG machine. The bits looks as follows. When the bearing is assembled it is a compact setup as below. The additional bits include a short lead screw extension which is both Loctited and pinned to be sure that the bits will not part at the wrong occasion. The pin is hidden under the conical sleeve which also moves the bearing housing to a better position for the handle. The housing has two bearings which lock the lead screw to eliminate any play or back-lash. At the end a new handle of the same type as the saddle handle will be fitted and the scale ring (to be done) will cover the lock ring that locks the lead screw to the bearings. The picture shows it all in semi-assembled state as there are some bits to be done and some paint to finish the whole thing off. To finalize the tail stock end of the machine will I also add the same type of handle to the tail stock. The handle will of course also get a scale ring and I am pondering on how to solve the position of the fiducial line, as it is now I think there is something missing between the tail stock and the hand wheel. Hmmmm  :scratch: Well, so far so good. It all seems to come together in a good way. Oh, I read through Bogstandards desription of Fixing Darrens Lathe, one of the most informative descriptions so far!  Comparing that with how I did I did not do all the measuring to begin with which I really should have done  :bang:. Of course I checked straightness and how true the datum faces were, and could find that on my machine it looked fine from start. Also checked the thicknesses of the gib strip surfaces with a mike and found them to be well within limits and consistent. The saddle had a small play at the head stock end, the same amount front and back. Not much and I took that out by cutting away about half of one of the shims in each pack. In hind-sight this must of course depend on the saddle to be slightly out of square as if it had not been accurately placed in its production jig. A minor detail now fixed. After doing these relatively easy adjustments and mods I find that the machine feels "tighter" and more stable which in turn will enable better finish and precision. At first it felt a bit scvary to dis-assemble the machine, but having read up on the matters in different places it really was not that difficult.  :D Work continues .... /Peter

Stilldrillin: Well done Peter!  :clap: :clap: I've stripped/ rebuilt sections of my mini lathe many times, over the past 8 years. It's always a bonus, when it feels, and works better afterwards.......  :thumbup: David D

Navigation

 Message Index

Next page

Previous page

Go to full version