Vicmarc chucks - no set screw?

[Alan Heffernan]

Use some anti-seizing compound on your spindle threads rather than plastic rings ect. It prevents seizing and wear and can be found in any auto store. Most brands also have threads and metal dust in the stuff which seems to prevent backing off. I have never used a set screw and turn and sand in reverse.

Robert, not sure I follow the logic here of putting antiseize on. It actually reduces the coefficient of friction and would reduce the forces/torque necessary for a spin off.

[Tom Albrecht]

I have two Vicmarcs. I drilled and tapped for two set screws on each one to hold it in the spindle groove.

And, BTW, if you buy direct from Vicmarc it's less expensive than buying from anywhere in the US including the shipping from Australia.

[Alan Heffernan]

I have two Vicmarcs. I drilled and tapped for two set screws on each one to hold it in the spindle groove.

And, BTW, if you buy direct from Vicmarc it's less expensive than buying from anywhere in the US including the shipping from Australia.

Tom, what lathe are you using?

[Prashun Patel]

I turn in one direction and sand in the other. Never use the set screw and never had an issue. But, my bowls are all less than 12" and under 30-40 lbs. I am not sure what would happen with larger stuff if turned in reverse.

[Brice Rogers]

The following comments are in regards to chucks unscrewing rather than on the benefits of various chucks.

I have a Grizzly G0766 and a Grizzly chuck. The chuck does not have a grub screw. The spindle has undersized threads and because of this, it is a bit too easy to unscrew the chuck. If I am sanding in reverse, I have to be fairly light on pressure as I have encountered times when the chuck would start to unscrew. The immediate symptom is a significant vibration - - kind of like "what the heck is happening". But if I stop sanding, hit the off switch or turn the direction control knob to fwd, the unscrewing stops. Luckily I was only sanding and at lower RPMs. If I was turning in reverse, the results could have been quite significant. So, I wouldn't dare to turn in reverse and only sand in reverse very lightly.

When I get a "round tuit", I'm going to explore making a drawbar for the chuck.

[Tom Albrecht]

Tom, what lathe are you using?

Currently on my Robust, formerly on a Oneway.

[Geoff Whaling]

One thing to consider - most insert systems, Nova, Vicmarc etc, use an inner and outer thread on their inserts. The grub screw secures / locks the insert to the spindle thread but there is no grub screw to secure / lock the chuck to the insert. The Oneway Stronghold Taperlock adaptor / insert by its design does not have a second thread.

Even though the insert / adaptor is locked with a grub screw it is still possible for the chuck body to unwind from the insert when turning in reverse.

[Doug Ladendorf]

Actually the Vicmarc has a grub screw that goes from the insert to the chuck. Position is parallel to the lathe bed when mounted.

[David C. Roseman]

Under the heading of what it is worth. I have two Nova's and two Hurricanes, the Nova's have grub screws and the Hurricanes don't. I ended up with a mixture due to seizing cheap purchase opportunity without contemplation of consequence. I have had large and out of balance lumps start to spin off when shutting down. I am not a mechanical engineer but I believe this is called an overhauling load. My ramp down speed is set pretty conservatively but still there it is. To be fair it has always been only a turn or two, but it scares the @@@ out of me. Between that and my routine of reverse sanding between grits, I have made a decision to look for another chuck system that incorporates a grub screw and which is heavier than the Nova.

I have adjusted the ramp down but at some point one does not want to wait extra long for the lathe to stop to protect from the occasional problem. To be fair this is not always a chuck issue as I have had large lumps spin down slower than the lathe and proceed to drill themselves via the dead center. The little guy does not have a chance. :}

Terry, no need to change chuck systems. If you'd be more comfortable with set screws for your Hurricanes, Steve Fulgoni at The Woodturning Store will drill and tap your inserts and install set screws (aka grub screws) without charge. He'll also pay the return shipping. See his post #18 in an SMC thread from February 2016: http://www.sawmillcreek.org/showthread.php?240665-Hurricane-HTC125-Chuck/page2

I think he's also started shipping his 1-1/4" x 8 tpi and M33 inserts with set screws standard. If heavy is what you want, I don't think you'll find a beefier chuck than your Hurricane HTC125. Mine is about 8 lbs.

[Bill Bulloch]

I have never set the set screw on any of my chucks to sand in reverse and have not had a problem. I don't have a vicmarc chuck, but do have the Grizzly chuck, which is suppose to be a copy. Of course it's not close to as good as the Vicmarc, but what I like about it is that the #2 jaws on the Grizzly expand larger and contract smaller than the #2 Jaws on the One Way or Nova. Since the Grizzly is suppose to be a copy of the Vicmarc I assume that the Vicmarc will do the same. Can anyone confirm this?

[terry mccammon]

Much obliged David. Now that you reference it, I do recall that Steve, who is a very nice guy, had posted to that effect. I was busy at the time and it did not register.

[Geoff Whaling]

Actually the Vicmarc has a grub screw that goes from the insert to the chuck. Position is parallel to the lathe bed when mounted.

That is correct for the later manufactured original Vicmarc inserts, however there are many out there without them which were manufactured well before VFD's were common.

Turners should get into the habit of checking the whole "system" and process for potential hazards asking themselves "what if?" "what happens when?" style questions for their existing processes and especially when they change an existing process or introduce a new process. It is easy to fall into the trap of changing something simple - and not take into consideration that their existing inventory of tools & accessories may not be such a good match now.

Changing something like a sanding process by using the reverse feature on a new lathe "to change direction between grits" may mean that older chucks & inserts are no longer compatible with that process and will present a significant hazard of a large work piece plus chuck or face plate unwinding from the spindle thread.