Chuck sizes

[Acharya Kumarswami]

I have a PM 3520 lathe and have been using a Vicmarc 100 chuck. I'm thinking of getting a VM 120.
Initially it was to avoid changing jaws, but I read that the 120 will give more stability. I'm hoping to learn more about that from some of you long-time turners. Would I experience a big difference, say, in turning 15 or 16" blanks of hard wood?

[Roger Chandler]

The larger chuck just allows you to turn bigger blanks............the 120 VM is a super chuck from what I hear........I have seen a couple and they are really nice. Bigger capacity means bigger jaw sizes and more weight can be handled with the larger size chuck.

[David E Keller]

I have the same lathe and both of the chucks you mentioned. I tend to use the larger chuck more than the smaller version as I like the heft it brings to the table. I think the size of the jaws has more to do with stability for turning larger pieces, or at least that's been my perception… The larger chuck will allow you to use larger jaws for those bigger pieces you describe. It's been said that you can't have too many chucks… I agree!

[Pat Scott]

I have the same lathe as you, and I have both the VM100 and VM120 chucks. I use the 120's for just about everything except the small stuff (peppermills and small boxes). The VM120 is not only bigger, it's a lot beefier as well. The chuck key is a larger diameter (VM100 chuck key is 5/16" diameter, VM120 chuck key is a little over 3/8"), and the chuck jaws seem twice as thick. What this means is you can grab a much bigger and deeper tenon and hold a much bigger piece safely. I wouldn't think of turning a 15" or 16" blank with the VM100, no matter how big of jaws it had (I have three VM100's, with the standard 2.5" jaws, as well as 3" and 4" jaws. Even with the 4" jaws, no way would I turn a 15" blank. The largest piece I might use the 4" jaws on is 9" diameter bowl). Yes you will notice a big difference between chucks! You'll wonder how you ever got along without the bigger chuck, or why you tried to turn such big pieces on such a small chuck. I have three VM120 chucks as well, mounted with 5", 6", and 7" Mega jaws. Having extra chucks just saves me the time and inconvenience of switching jaws. I started off with one chuck body (without jaws), added the 5" jaws, then gradually added new chucks and new jaws as money allowed.

The tenon for a 15" to 16" bowl should be 40% of the diameter, or around 6" to 6.5". You can't get that big using the VM100, even if you had 5" jaws on it. For that size tenon I would use my VM120 with 6" jaws (the 6" jaws will grip a tenon from 5" to 6-3/4"), or the 7" jaws (that grip 5-7/8" to 7-1/4"). The VM120 with the right jaws will hold a 15"-16" bowl with ease. Making the tenon smaller so that it will fit in a VM100 is asking too much from the small chuck. A blank that big is heavy, and no matter how tight you make the jaws, that's just too much weight for it to hold in my opinion.

[Reed Gray]

More mass = more stability. I had a PM, and now have a Robust American Beauty. I have several of both of the Vicmark chucks. I use the large one on almost all of my bowls, up to 14 inch diameter and a recess. The standard jaws, in a recess, will hold fine for that size bowl. On larger ones, I will use larger jaws.

I guess the best way to explain it is I turn some tops from maple baseball bat blanks, with rough stock at about 4 inches long, and 2 3/4 inch wide. With a dove tailed tenon on one end, if I use the small chuck, I get vibration when turning the tops unless I am very gentle when turning. With the large chuck, I get almost no vibration, no matter how aggressive I am when turning. Big difference.

robo hippy

[Acharya Kumarswami]

Thank you. I can see that the 120 is going to help my work a great deal. When you mention the standard jaws, did you mean the 2-1/2" jaws that come with the 120? Right now my funds are quite limited, so I'm needing to make a choice of just one set of jaws, and whether to get the 120 with the 2.5" jaws or without.

[Reed Gray]

I think the standard jaws are 2 1/2 inches wide. I know for sure that they fit nicely into a 2 5/8 inch forstner bit recess, with just enough room to expand for a good tight fit.

robo hippy

[Mike Peace]

If you are committed to the VM120 you can ignore this. If you are on a tight budget you may want to consider the Nova Titan chuck at 8 lbs and 5" in diameter that comes with PowerGrip jaws. I recently bought mine from Amazon for less than half of what a VM120 would cost and Teknatool makes fine chucks. You can also find them at the Woodcraft site. http://www.woodcraft.com/product/208...4-x-8-tpi.aspx

They frequently go on sale at WC. Amazon is out of stock but had them for $207 recently.

[Reed Gray]

One of these days, I will have to buy and personally compare the Oneway, Nova, and Vicmark chucks. Maybe Axminster (spell?) as well. Lots of toys. I have one friend who has all Oneway chucks. He has been production turning for almost 20 years, but mostly smaller bowls. He said the reason he has Oneway rather than Vicmark is that a friend was selling all his chucks and they were Oneway.

robo hippy

[Pat Scott]

I thought it might be nice to have different brand chucks also, so I bought a SuperNova2. It was a nice chuck but I didn't even think the jaws would not be interchangeable between brands (the screw holes are different between Vicmarc and Teknatool). I already had several Vicmarc chucks and jaws so I sold the SuperNova. No matter what brand you go with, you'll want to stick with that brand. If there is a chance you will want different size jaws in the future, make sure they are available before buying.

[Michelle Rich]

the vicmarc is an excellent choice. they are my preference ( I have all) and one of the reasons is the # of jaws available..nice to have that in your arsenal, over time. the other reason is they are built tank tough.

[Pat Scott]

Craft Supply has an article on "Learn to pick the right woodturning chuck and jaws".

http://www.woodturnerscatalog.com/store/article/56

[Dave Ogren]

I also have a couple of VM120 chucks. I have turned over 20" dia. bowls using a just over 2 5/8" dia. by 1/4" deep recess with no problems at all.

Good luck,

Dave

[Bernie Weishapl]

Don't have a 3520 but do have both the VM100 and VM120. Use them both regularly. The VM120 hold big out of balance pieces more secure.

[Jeffrey J Smith]

If you look around, there are some options. I've got Oneway chucks, a couple of Strongholds and a couple of Talons. That said, I found a set of Vicmark jaws that I bought at the Craft Supplies garage sale (super wednesday sale the day before the Utah symposium every year) that were made to fit the Stronghold. They are great jaws, and fit perfectly. Kind of like a set of 3-1/2 smooth dovetail jaws. I paid less than $15.00 for the set. I liked these jaws so much that I bought a set of slides for the Stronghold that take Vicmark jaws. Kind of the best of both worlds. One Stronghold chuck for Oneway jaws, one setup for Vicmark jaws.
I don't know if Oneway makes these slides any longer. They were called Versa-Slides and came in oneway packaging. I got them through Craft Supplies a couple of years ago - I think they may have been on closeout.