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| C3 Upgrade and improvement - I hope |
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| PeterE:
Well, then it was time for me to start the necessary job to upgrade and hopefully improve the C3 mini-lathe. The reason for starting right now was that the other day I heard a clonk and the lower half-nut dropped out by itself. It must have loosened by vibrations and I have not noticed it before as I seldom actually use the power feed. So, time to start following the descriptions from Model Engineers Workshop regarding this. Out came the lead screw, set up and drilled for the extension to take the lead screw handle, and then put aside for later. Off came the apron as next step. Everything looked quite OK. Not much swarf around the hand wheel gears and otherwise looking good - apart from that the gib strip for the half nuts was also missing - dropped out together with the lower half nut. Made a cover for the lead screw gears from a piece of acrylic from the scrap box. Had to thin the gears a little so they would clear the new cover and gave them a small dose of bearing grease as lubrication. So far so good. The picture shows the apron back together again. Still pondering about if I should make some better "dimples" for the gib strip as well as wondering if I should make a better "hold-down clamp" to replace the two screws with washer that do just that. The present solution feels a little too cheap as a long term solution. Does anyone know if the gib strip is hardened? Just so I know what drill to choose. The grease I use is a bearing grade grease of which I have to use very little. A standard Lithium-based bearing grease good enough for car wheel bearings and the like. Should do well also for my machines I think. The jorney has just begun .... BR /Peter |
| ParCan:
"Does anyone know if the gib strip is hardened? Just so I know what drill to choose." The Gibb strips on my Chester Conquest, the same machine I think, were not hardened. I had the same issue with the 1/2 nut. I just made the dimples deeper (around 1mm). Alex |
| PeterE:
--- Quote from: ParCan on July 09, 2012, 01:28:45 PM ---"Does anyone know if the gib strip is hardened? Just so I know what drill to choose." The Gibb strips on my Chester Conquest, the same machine I think, were not hardened. I had the same issue with the 1/2 nut. I just made the dimples deeper (around 1mm). Alex --- End quote --- Thanks a lot Alex :thumbup: I will go for a center drill then. BR /Peter |
| PekkaNF:
HI, Haven't done this mysef yet, but I have to refurb one lathe after I have TLCd other one to full "production specs" :D I did some rechears on this kind of gibs. One book (The Model Engineers Workshop Manual by Geo.H.Thomas if i remember correctly) and several notes in net led me to beleive that conical ends of set screws tend to "wedge" the gib firmer to the dove way when slide is moved. Apparently you should drill an extra hole and pin gib stationary and/or use dog point set screw to take up the slac. Pekka |
| PeterE:
--- Quote from: PekkaNF on July 10, 2012, 05:53:33 AM ---HI, Haven't done this mysef yet, but I have to refurb one lathe after I have TLCd other one to full "production specs" :D I did some rechears on this kind of gibs. One book (The Model Engineers Workshop Manual by Geo.H.Thomas if i remember correctly) and several notes in net led me to beleive that conical ends of set screws tend to "wedge" the gib firmer to the dove way when slide is moved. Apparently you should drill an extra hole and pin gib stationary and/or use dog point set screw to take up the slac. Pekka --- End quote --- Exactly what is in my mind Pekka! I also have the George H Thomas book - really good! - and will follow his intentions when fixing the half-nut dove tails. There are three set screws to "fix" and set the gib strip and they will all get deeper points together with a new hole for a securing pin to remove the risk of the gib strip to fall out again. Furthermore there will be a longer and wider piece of plate to hold down the gib strip instead of the flimsy washers used today, and perhaps a few other "improvements". BR /Peter |
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