spindle lock question

[scott m]

Hello, I have made a spindle locking device for my Logan lathe that consists of a al. block bored out to fit the back of the spindle and is split on the side so a bolt can tighten it down. The whole contraption is bolted to the headstock and I would like to leave it there and am concerned about bearing wear. It rubs just a little as the spindle goes round, and I wonder it this would be cause for concern in the long run. I got this lathe from my grampy and don't want to have to tear into it if it does hurt the bearings. I just found your forum and this is my first post. I have some experience in the homeshop and hope to learn as well as help out when I can. Thanks for any ideas. Scott. P.S. You have interesting smilies..........

[Ken_Shea]

Scott, are you able to post a picture ? that would help, are these open bearings that could get contaminated by wear particles ?, can't you hone it out a bit to relieve this rubbing ?, I am having trouble imagining it.

Ken

[scott m]

Ken, I don't quite know about the bearings, I think they are sealed. I dont think I can hone it out and still get a nice even grip around the spindle, I think that would make it grip on just top and bottom. It needs to be a postive lock so I can index gearblanks for cutting. Here is a picture if I can get it to work, I am not used to the controls on this forum. You can see the block on the back and I have to remove gears to get the thing on there. I would like to leave it in place during normal turning operations. Scott.

[Ken_Shea]

OK, I see Scott, I do not see where a little (emphasizing little) rubbing will cause a problem, it will soon wear in. You could still hone/ream the part precisely by tightening the bolt just a bit for some tension, hone or ream then back off the bolt while running, this should provide even a more precise fit.

[scott m]

It didn't even occur to me that natual honing action would take place. Now I can turn without a worry. Well, I can see already I will learn a lot here, hope to help out too. Thanks. Scott.

[Ken_Shea]

Keep an eye open for excessive wear in particles, after a while you may want to remove the block, you will quickly see the wear (or high spots) then you could just sand them down a bit, perfect is not always necessary, but always better

[HuFlungDung]

It does make me a little nervous that the thing might suddenly seize one day, but I suppose your belt will just slip before it tears anything apart (depending on the spindle momentum when the seize occurs). A dry "bearing" has a way of filling up with dust or grit that could provoke an "event".

I hope your spindle is rolling bearings and not babbet.

There's nothing stopping you from drilling a lubrication hole in your brake block. Even oiled, the clamping will be sufficient for gear cutting. Lots of machine spindles run with multidisk clutches that have oil flowing between the plates and they still clamp.

Another way would have been to make a split bearing with a cap (like a connecting rod in an engine). Remove two bolts and take half of the surround away.

[scott m]

Another way would have been to make a split bearing with a cap (like a connecting rod in an engine). Remove two bolts and take half of the surround away.

Rats. That would have been the ideal answer to this fixture. Makes me want to post questions on my projects beforehand . I may just saw off the top of that block, after drilling and tapping another hole, of course. Good info on what to look out for as well. Scott.

[Ken_Shea]

Scott, one way to determine if it is about to give you trouble is that it will get hot, just keep an eye, err.... i mean finger on it from time to time until you are satisfied all is OK.

I like the style you have, it is quicker and you could also incorporate a camming lever to lock and unlock instead of the bolt.

[scott m]

Ken, I like that idea a lot. No wrench to fuss around with just a lever to turn. It could even give me an excuse to use my radius attachment and make a ball end for it (lever). It isn't finished yet because it is 1 part of 3. There is the spindle lock, spindle indexer and a crosslide mounted gear cutting attachment which I am stalled out on right now on how to power it because my first idea was a failure. I sure appreciate all these fine ideas. What is a chipsweeper? I have an idea........... Scott.

[Ken_Shea]

Scott, A chipsweeper is where everybody starts and is only related to being a new CncZone member and poster, as your input/post increase the name changes to reflect your virtual machinist capabilities.

[scott m]

That's what I thought, have to start somewhere just like anything else. I have one more general ot question if I can press your patience. Is there any way to make my screen show more replies so I don't have to page through all of them to look at the most recent? I looked around but can't figure it out. If it is obvious and I missed it, sorry. Scott.