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Broken lathe screw center screw

Posted: Fri May 22, 2020 5:53 pm
by Tyer
I picked up a couple of clarinet bell blanks, of all things, at Woodcraft, and was setting up to turn a ring holder for my wife. Because the design I have in mind will form a shallow dish near the perimeter, I didn't want to use a regular faceplate, because the screws would intrude into this dish area. So I decided to use the screw center, with which I've had pretty good luck in the past.

However, I didn't figure on just how hard African Blackwood is, so I didn't drill a large enough pilot, and snapped the screw off. This led to two problems: where to get a replacement screw, and how to get the stub out. The latter I solved (sort of) by using a plug cutter to drill around the screw, then using a chisel (a cold chisel - this stuff is really hard!) to split the wood along the screw so I could back it out with vice grips. I'll use a Forstner to clean up the hole, but my original fastening method is shot. Oh well - I have two blanks, so I'll use this one for something else.

The first issue though is my current problem - where do I get a replacement screw for this? It's a #14 x 1-1/8" flat head wood screw, and I'm wondering if it's a special high-strength type (not high enough, obviously), because it's black like the rest of the center, which is definitely hardened somewhat (my vice jaws didn't mark it at all, for example). I'm on my way to Home Depot to get a package of #14 x 1-1/4", but I'm certain they'll be of the cheapest possible Chinese steel, so I've also ordered some stainless screws on Amazon, but what I'd really like is a grade 5 or grade 8 screw (not that wood screws are ever graded that way, of course).

Shopsmith doesn't appear to sell the screw separately - anybody have an idea about sourcing this without buying a whole new center (which I won't do...)?

(Picture of the problem: https://markesystemsinc.box.com/s/ej0ps ... 112kqncfw1)

Re: Broken lathe screw center screw

Posted: Fri May 22, 2020 6:26 pm
by chapmanruss
The screw for the Lathe Screw Center is a common 14 x 1-1/4" Wood Screw and can be found at most hardware stores. I have bought a replacement at Ace before. The only difference is it will not have the black coating but if your Screw Center is from before 1964 in didn't have the black coating anyway.

Re: Broken lathe screw center screw

Posted: Fri May 22, 2020 6:33 pm
by reible
OK a couple of things. My vintage screw was not black oxide finish. Typically you see black oxide on drywall screws. Never ever drywall screws for holding thing on the lathe. They are brittle and that is not what you want.

Next, stainless steel is more then likely a bad choice too. They are in a finish that is best for corrosion resistance rather strength. Yes there are exceptions but most of the time there is no data on them to tell you what you are really getting.

You want screws that are ductile.

You can go to a hardware store and pick one out of the bin and it will very likely be just fine. You don't have to stay with slotted either. I have had to replace some of these on machines I have bought used so either lost or broken and that is what I have done and it has worked out fine.

Ed

Re: Broken lathe screw center screw

Posted: Fri May 22, 2020 8:59 pm
by Tyer
OK, thanks all. I did pick up some #14 x 1-14 at Home Depot, and they look like they should fit - plus I actually prefer the cross-point head, even though there's a bit less torque to be had with the driver.

I selected stainless because the ones I purchased are 304, which is not as corrosion resistant as say 316, but is tough as heck - way tougher than the mild steel of common screws (especially the ones being made nowadays). But the ones I got should get me through this project anyway.

Anyway, thanks again for the responses!