Woodworm screw not holding

[John Berdoulay]

Fairly new to turning. I have a Nova chuck and a 3/8" woodworm screw. It has happened several times now where I cannot get the screw to hold in the piece. It strips the wood and just winds up spinning. Then I wind up with a useless piece of wood with a big hole in it. I know that I can drill a smaller hole but that's not really the point. I want to be able to do it like the instructions say- "drill a 3/8" whole and turn the piece on the screw to seat it.". Any ideas as to why this isn't working for me?
Thanks.

 

[Larry Komroff]

I am seeing that the drill size is 5/16". That could be your problem. Woodworm video It could also be that the wood you are using is soft, wet or you are putting it into endgrain

 

[Timothy White]

You can pack the hole with shavings and wood glue let dry redrill 5/16 for nova screw.

 

[Brian Gustin]

also sharpen your gouges. the less cutting effort and/or catches, the better.. I have had woodworm screws strip the hole in nice hard solid woods after a bad catch, and lesser wood just because I had not yet learned when to sharpen my gouges (and/or getting them properly sharp in the first place!) - if you even THINK you might need to sharpen your gouge, it's probably way past time to sharpen.

 

[Roger Chandler]

Most worm screws I have used have threads bigger than the 1/4" shaft of the screw itself. I have 5 Nova chucks, 4 SuperNova 2's and one original supernova. The instructions, if I recall correctly say drill a 1/4" hole, same as the worm screw diameter shaft, and let the bigger threads bite into the wood. I've never had a worm screw done that way spin off the threads. Sounds like your hole is too large for the screw to get bite.
That being said, my chucks are probably 10 years old, and I do not know what size the newer worm screws are now, nor what the new instructions coming with the chucks are now......so, adjust accordingly!

 

[Dean Center]

I'm a guy, so I don't read instructions, but I drill a 5/16 inch hole for the Nova screw and it works well most of the time. For really hard woods, it's a little hard to thread the wood on and off, and I probably should drill an 11/32 hole. Some punky woods don't hold the screw well, but if you have your tail stock up snug, it'll still spin the wood.

You're drilling into the top/open side of the bowl, so it really shouldn't make any difference if it tears a little--that wood will get turned away momentarily.

 

[Tom Lucas]

I've also had issues with the Nova worm screws. To me, they are too short. My Vicmarc screw is at least 1/2" longer protruding beyond the jaws. What a difference between the Vic and the Nova holding on a worm screw. I've had some luck with the Nova, if the wood is good and solid. But, generally I don't use my Novas with a wormscrew. I just don't trust them. I'll use a faceplate if my Vic is occupied.

 

[Lou Jacobs]

I agree with everyone who says use a 5/16” hole. Yesterday I finished roughing out a batch of 25 oak, ash and soft maple bowls. All on the nova chuck with the woodworm screw. The nine or so largest bowls (12-14”), I used tailstock support. The rest, between about 6-10”, just the screw. You can judge by how tightly the stock snugs up on the screw, if you’re going to have any difficulty. If I’m unsure, I stop and check that it’s still tight after the first few passes.

 

[Timothy White]

Oneway screws use a 3/8 drill vicmark and nova use a 3/8 drill

 

[Jon Rista]

I recently started turning platters, and looked up the recommendations for my Nova woodworm screw, which was 3/8". I ALWAYS check my bits against the shaft of any screw, though...and 3/8" was nearly as wide as the THREADS on the woodworm screw that I have. So I used a smaller bit, and tightened my blanks all the way until they were tight up against the chuck. The early holes still seemed to be too large, though, as after getting some of the platters turned each time, the blanks were very slightly loose. I dropped the bit size again (I think it was 1/4" but I'm not certain, I have to double check now), and things held tightly every time.

I know that the OneWay screws are specifically designed to work in a 3/8" hole... I'm skeptical about the Nova. I think the docs should say that its a 3/8" diameter thread, but the shaft of the one I have is definitely smaller than that.

 

[Mark Jundanian]

The proper drill bit size for the Nova woodworm screws is actually 8 mm. The closest imperial size is 5/16".

 

[Russell Nugent]

I recently started turning platters, and looked up the recommendations for my Nova woodworm screw, which was 3/8". I ALWAYS check my bits against the shaft of any screw, though...and 3/8" was nearly as wide as the THREADS on the woodworm screw that I have. So I used a smaller bit, and tightened my blanks all the way until they were tight up against the chuck. The early holes still seemed to be too large, though, as after getting some of the platters turned each time, the blanks were very slightly loose. I dropped the bit size again (I think it was 1/4" but I'm not certain, I have to double check now), and things held tightly every time.

I know that the OneWay screws are specifically designed to work in a 3/8" hole... I'm skeptical about the Nova. I think the docs should say that its a 3/8" diameter thread, but the shaft of the one I have is definitely smaller than that.

Where did you find that recommendation? Everything I've found recommends 5/16 or 8mm unless using a very dense hard wood then you may want to use a 3/8.

 

[odie]

Out of curiosity, I mic'd the screw on one of my PM center screw faceplates. I've always drilled the pilot hole to 1/4", and the outer most threads measure about .272".

This seems to hold great. Occasionally, some hardwoods are a little difficult to screw on to where it seats fully, but a strap wrench is all that's necessary to screw all the way, and remove bowl blanks.

-----odie-----

 

[Bill Blasic]

My Nova screw that I have been using for the last 18 years or so mics out at .420 OD. If I'm turning softwood I use a 21/64 (.328) drill and if it is hardwood I use a 23/64 (.359) drill. Using these drills almost all the time I have to loosen the jaws and take the piece out and using a pair of water pumps I unscrew the Nova screw. I start just about everything I do on that screw. As stated for over 18 years same Nova screw (I have about 16 or so extras in a drawer).

 

[Bernie Hrytzak]

Another way of determining drill size is to mic the minor diameter of the screw and select the drill bit at that size. This method works regardless of screw manufacturer except in very dense woods where you might have to have a slightly larger hole.

 

[robo hippy]

I used a worm screw maybe twice. I gave it up in favor of a drilled recess, using a big forstner bit. Far more efficient. It doesn't seem to need to be dove tailed as I have never had any slip or fall off. 2 5/8 bit for my Vic chuck, the medium sized one.

robo hippy

 

[Jon Rista]

Where did you find that recommendation? Everything I've found recommends 5/16 or 8mm unless using a very dense hard wood then you may want to use a 3/8.

I'm not sure where I read that, was some time ago. I just checked the shaft against my 8mm drill bit, though, and its a dead-on match. I'll be using that from now on, unless the wood is particularly hard.

 

[Bill Blasic]

Jon if an 8mm (.312") drill bit is the same size as your wood screw it is not a Nova screw. I have at least 16 of these Nova screws and they are all .415" to .421". I seriously doubt that I could get the softest wood to accept the .420" Nova screw into a .312" hole. Are you sure you don't have a Vicmarc screw? Vicmarc screws are thinner and the suggested screw size hole is 7mm or 8mm.

 

[Earl McLain]

My screw shafts fro Nova G3 chuck purchases measure 5/16” or 8mm. Wondering if the larger that Bill references might be from Titans or older SuperNovas? I also have wormwood screw from recent SuperNova 2 that measures 5/16”. Regardless, caliper is my friend!
Earl

 

[Kirk Amidon]

The woodworm with my nova G3 requires a 5/16 hole.

 

[Jon Rista]

Jon if an 8mm (.312") drill bit is the same size as your wood screw it is not a Nova screw. I have at least 16 of these Nova screws and they are all .415" to .421". I seriously doubt that I could get the softest wood to accept the .420" Nova screw into a .312" hole. Are you sure you don't have a Vicmarc screw? Vicmarc screws are thinner and the suggested screw size hole is 7mm or 8mm.

Its definitely a Nova, it came with my G3 chuck. By my calculation it would actually be 0.315" (8/25.4), but I'll do some actual caliper measurements here. I just eyeballed it before, but the two look to be exactly the same size.

 

[Mark Jundanian]

See the preparation section of the manual.

Just saying.

 

[Mike Peace]

"When all else fails, read the fine print." Most of the teknatool chuck manuals have pretty good instructions but I notice the manual for the Precision Midi neglects to state the screw size. I have 4 different model Teknatool chucks. I did a video on using the WW screw and it includes a few useful tips

View: https://youtu.be/EI-utYAfXJI

 

[Dean Center]

My screw shafts fro Nova G3 chuck purchases measure 5/16” or 8mm. Wondering if the larger that Bill references might be from Titans or older SuperNovas? I also have wormwood screw from recent SuperNova 2 that measures 5/16”. Regardless, caliper is my friend!
Earl

Bill is measuring the OUTSIDE diameter of the threads and others are talking about the diameter of the shaft. Apples and kumquats.

 

[Leo Van Der Loo]

The standard 1.5" long Oneway Jumbo screws call for an 9mm hole 19mm deep that is 11/32"X 3/4".

For larger and softer wood blanks, Oneway also makes a 2" long jumbo screw in both RH and a LH threaded one for outboard turning.

The Oneway Jumbo screw is held safely in two ways, by the thicker fluted part held by the base jaws and by the machined jaws edge in the groove in the Jumbo screw.

The very nice and sharp thread cuts nicely into the wood, though with very hard and dense wood you might need to drill a slightly bigger hole.

 

[Gerald Lawrence]

Like Bill I scrambled around the size drill to use and came up with 23/64 and it works.

Leo the Nova screw works the same way .

As to screw length my G3 has a longer screw due to the deeper jaws. Most I have heard are ok with the length and sometimes need to shorten it using a spacer. By the way using a spacer wider than the jaws will also give mor grip on the bowl.

 

[Leo Van Der Loo]

Leo the Nova screw works the same way .

They do now, but I remember that they did not, and would slip around in the jaws, so the chuck had to be cranked hard, things have gotten better over the years as I do remember chucks that came in pieces and could only grip the precise turned dimensions, of course no all ideas ar winners

Also the problems they had with jaw sets that did not make a matched set, that took a while to straighten out.

 

[Michael Edelman]

From the Nova manual:

”NB: Recommended pre-drill size is 9/32” (7mm) for soft woods and 5/16” (8mm) for hard woods.”

that’s what I do, and I haven’t had any problems. A friend reminded me to make sure the screw was as far forward as possible, and to check that the work was tight on the screw periodically.

 

[John Berdoulay]

OP here. Thanks to everyone for their help on this. This was my first post and I am blown away by the support. Wound up drilling the 5/16" hole for 3/8" screw and that seemed to work well (this time!).

 

[John Berdoulay]

OP here. Thanks to everyone for their help on this. This was my first post and I am blown away by the support. Wound up drilling the 5/16" hole for 3/8" screw and that seemed to work well (this time!).

Then I made my bowl too deep and went through the bottom. Buckle Up! This is going to be a lonnnnng ride. I'll be talking to you all again soon.

 

[Bill Blasic]

Yes I am using the OD of the screw as when I use the OD of the drill I know that with hard wood I am holding with .030 on a side and softwood I am holding close to .050 on a side. The wood screws on without difficulty and it never comes loose.

 

[hockenbery]

Then I made my bowl too deep and went through the bottom. Buckle Up! This is going to be a lonnnnng ride. I'll be talking to you all again soon.

That happens to most of us.

Learning to use calipers for the sidewall down to the Chuck tenon will keep you from unexpectantly going through the bottom.
Planning ahead helps too you will want to turn the inside of the foot so leave enough thickness.

Practice practice practice

 

[Jon Rista]

I measured my woodworm screws with calipers. This includes some Novas, as well as a Record Power. The diameter of the shafts range from 0.2955" - 0.297" while the diameter of the threads range from 0.415" - 0.42". The diameter of my 8mm bit shaft is 0.3147". So, it makes sense that you would use an 8mm or 5/16ths bit...you WANT the majority of the threads to bite into the wood. I've been using an 8mm bit now, and the hold is excellent, no loosening of the blanks at all now.

 

[Rusty Nesmith]

Then I made my bowl too deep and went through the bottom. Buckle Up! This is going to be a lonnnnng ride. I'll be talking to you all again soon.

You are not alone. Everybody I know has made some beautiful firewood in the beginning. I still do once in a while.

 

[Jon Rista]

You are not alone. Everybody I know has made some beautiful firewood in the beginning. I still do once in a while.

Yeah, I had a few bowls explode on me early on. The first one, I was trying to create a bowl with an overhanging rim, and I was too inexperienced...when trying to hollow under the lip I pushed on the other side of the bowl too hard with the bar of the gouge, and boom...it was instantly in pieces.