Grizzly 766 and Vicmarc 120 Chuck

[Steven Park]

Last week I tried using the McNaughton coring system and got some really bad catches. These catches caused the chuck adopter to over tighten and screw itself on the shoulder just behind the spindle threads. When this happened the chuck is now not centered. Is there a different adaptor that sits flush to the back shoulder of the spindle? Need some advice on what to do to fix this

Link to video example: https://www.instagram.com/p/Bc09xkkguPN/?taken-by=10x10_turning

 

[Richard Coers]

The adaptor MUST be against the back shoulder. The Grizzly 766 is known to have too large of diameter on the shoulder and would not allow aftermarket chucks and adaptors to screw on far enough. Many owners used a file to reduce the diameter on the shoulder. Is that a Vicmarc adaptor? Also a known issue that some aftermarket adaptors are of poor quality.

 

[Steven Park]

The adaptor MUST be against the back shoulder. The Grizzly 766 is known to have too large of diameter on the shoulder and would not allow aftermarket chucks and adaptors to screw on far enough. Many owners used a file to reduce the diameter on the shoulder. Is that a Vicmarc adaptor? Also a known issue that some aftermarket adaptors are of poor quality.

do you know of anyone or how to file down the diameter?

 

[William Rogers]

I don't have that lathe. However you can search the members for Roger Chandler and post here sometimes. I would send him a message with your question. He is very knowledgeable regarding the G0766. I'm sure he can answer

 

[Steven Park]

I don't have that lathe. However you can search the members for Roger Chandler and post here sometimes. I would send him a message with your question. He is very knowledgeable regarding the G0766. I'm sure he can answer

ok thanks for the help

 

[john lucas]

I have a couple of aftermarket chucks that resemble the Vicmarc. I have trouble with both of them not screwing on all the way to the face of the spindle. The Grizzly I put on the metal lathe and opened up the adaptor a little and it now fits like a chuck should. It should screw on past the little shoulder and flush against the face of the spindle. the other one is too shallow. The end of the spindle hits the bottom of the inside of the chuck. For that one I made a small ring that fits on my spindle and is thick enough that the chuck can screw against that. It works perfectly that way. the Vicmarc chucks of which I have 3 of different ages all work perfectly. I also had problems with both aftermarket chucks where they were hard to tighten. The small gear on the inside was worn just in the middle. It doesn't match the ring gear very well which is what caused the wear. I replaced this pinion gear on both and neither one of the new gears fit very well and had to be modified by hand to work well. The vicmarc chucks are far older than these 2 aftermarket and used more and still work like day one.

 

[Steven Park]

I have a couple of aftermarket chucks that resemble the Vicmarc. I have trouble with both of them not screwing on all the way to the face of the spindle. The Grizzly I put on the metal lathe and opened up the adaptor a little and it now fits like a chuck should. It should screw on past the little shoulder and flush against the face of the spindle. the other one is too shallow. The end of the spindle hits the bottom of the inside of the chuck. For that one I made a small ring that fits on my spindle and is thick enough that the chuck can screw against that. It works perfectly that way. the Vicmarc chucks of which I have 3 of different ages all work perfectly. I also had problems with both aftermarket chucks where they were hard to tighten. The small gear on the inside was worn just in the middle. It doesn't match the ring gear very well which is what caused the wear. I replaced this pinion gear on both and neither one of the new gears fit very well and had to be modified by hand to work well. The vicmarc chucks are far older than these 2 aftermarket and used more and still work like day one.

Awesome! Thanks for the advice. I contacted a CNC shop earlier today and they suggested the same thing. Would you mind posting some photo of the adapter and the small ring you made? It would be very helpful when explaining this to the shop.

 

[Roger Chandler]

I just saw this post. Dick mentioned the area called the spindle boss. There is a thread about this on the Grizzly Green Monster Group at SawmillCreek. Just go to the turning forum, then click on the community tab at the top of the page, and then groups......you will see the GGMG. What it happening is that the manufacturer made the diameter of the boss at 1.260" diameter and most aftermarket inserts have a 1.250 diameter, but not all chucks. Grizzly chuck fit without any mods, so my guess is they do this for trying to sell their brand of chuck. A truly easy and quick fix, so hope you will look the GGMG up at sawmillcreek. There are other helpful ideas for you there also.

 

[Jack Lilley]

I had the G0766 for 1-1/2 yrs. My hurricane chuck would screw on tight but my nova chuck would not. I filed the shoulder and had no problems after that. It is very simple. I used a flat file with the lathe rpm's as low as it would go, takes less then 5 minutes. There is lots of information about this on sawmill creek forums.

 

[Bill Boehme]

As other have said, it is the back shoulder of the spindle that provides the alignment registration. Threads are only for fastening and aren't of sufficient tolerances to properly align the chuck. There are at least two solutions:

• Counterbore the back end of the chuck adapter insert to clear the boss that is oversized. A machine shop would be able to do that. Just tell them what diameter and how deep. The diameter isn't critical as long as it is enough and the depth looks like ⅜" or so would be sufficient.
• Use a shade tree milling machine (a file or sandpaper) to reduce the diameter of the boss on the spindle. Try not to scuff the registration face.
• Another possibility is that you could also contact Grizzly and describe the problem. They might give you a new spindle that might be better, but don't hold your breath too long.
• You could also use some sandpaper to slightly enlarge the bore on the back end of the adapter. From what you have described, it wouldn't take much to enable the adapter to screw all the way onto the spindle.

BTW, your video was great for illustrating the problem.

 

[Roger Chandler]

I should also have mentioned something that Dick also references. Not all aftermarket inserts are to exact tolerances. They are basically all over the place. I have 5 SuperNova chucks, with 3 different inside diameters. I have 4 Hurricane chucks, which are much better and more consistent in machining. Nova adapters have been the worst for me.......I actually had to enlarge one of them and it was a genuine Nova insert. I held it in a chuck which ran true, then took a hardened file and reamed out the opening a bit. I then took abrasives and polished it up to acceptable.

I think one thing that happens is that when Nova manufacturing went over to China, they had issues with inconsistent machining from run to run. The one adapter that I had to ream out was purchase about two years after two of my other Nova chucks. I later got two more of them, and I am supposing that the adapters came from different manufacturing runs, with the time being as far apart as it was. I just know that machining is not always exacting, and in China, the QC is not always the highest priority it seems!

 

[Steven Park]

Thank you everyone for your very helpful advice

 

[john lucas]

Steve I could shoot a photo but it's nothing more than a fat washer. 1 1/4" inside to barely fit over the spindle and outside diameter is probably 1 3/8". It's about 1/4" thick because that is all that was needed.

 

[Tom Gall]

Last week I tried using the McNaughton coring system and got some really bad catches. These catches caused the chuck adopter to over tighten and screw itself on the shoulder just behind the spindle threads. When this happened the chuck is now not centered. Is there a different adaptor that sits flush to the back shoulder of the spindle? Need some advice on what to do to fix this

Link to video example: https://www.instagram.com/p/Bc09xkkguPN/?taken-by=10x10_turning

A machined 1-1/4" ID spacer should have enough clearance to fit over that slightly larger diameter on your spindle. This link (Grizzly catalog) is for a 1/4" wide spacer (#1174) which will most likely work or you can go for a 3/8" (#1175). Better quality ($$$) and a wider range of widths can usually be found in most industrial catalogs such as MSC, McMaster-Carr, Grainger, etc.

W1174

 

[Roger Chandler]

I think it is better by far to file down the spindle boss rather than use a washer/spacer. This will allow the threading all the way back to the shoulder as it should be and give the most secure hold. The G0766 was manufactured with metric dimensions, because it is sold in Europe and Asia under different labels, but it does have the 1.25x8tpi spindle.

Those metric dimensions on the spindle boss, and the 25mm banjo hole is what trips folks up. Two of the easiest and quickest fixes that it is beyond me why anyone would want to not do them. I bored out my banjo hole by 1/64th inch to make it accept standard aftermarket toolrests with a 1" post, and makes it also take most accessories such as coring and threading jigs......smartest way to go.

The spindle boss just takes a flat file with the lathe running at about 500 rpm, testing the fit two or three times as you go, so as to not take too much off. Polish it up with 400, then 600 grit and it looks like new.

 

[Steven Park]

I filed down the spindle boss just enough last night so now the vicmarc 120 and my oneway face plate both screw on perfectly and butt up against the back. Thank you everyone for a easy solution

 

[Roger Chandler]

I filed down the spindle boss just enough last night so now the vicmarc 120 and my oneway face plate both screw on perfectly and butt up against the back. Thank you everyone for a easy solution

Cool Beans, Steve! I knew you'd be happy!