Threading lag bolts , etc - how are the tips done?

[Eddie Mullins]

OK, I have searched but haven't found the asnwer. I'd like to make make some bolts or hooks/hangers that are threaded to screw into wood. I don't plan on the becoming a habit necesaarily, but want to go through the process and use a few is some applications. I have a die and can thread the shaft, but how are the threads done out to the tips of lags bolts and the like? Cut with a file?

 

I'm thinking with a pre drilled hole a threadded tip isn't really even needed, but I may not always want to do that so I'd like to at least know how and give it a shot.

[Frosty]

Mark and file is probably the easiest to describe and  yields the better results. Another technique I've had limited success with is twisting it. Twisting a taper uniformly is a tough row to hoe. If it isn't uniform the threads will fight each other and it'll strip or just be too hard to screw in.

 

So, here's what I tried. Taper a short square point on the thickness stock you want for the shaft. Thickness of the screw is measured across the diagonal, this will become it's diameter when twisted. For sharp threads fuller the faces shallow but wide almost to the corners. Now, with the shaft and point formed and (fullered if you're cocky), comes the hard part. You'll need a twisting wrench that fits the bottom of the fuller or it'll make curled mush of the threads. A flat jawed wrench for the not too cocky smith is good. Twist the straight part, easy peasy, get it tight enough to be a screw.

 

Twisting the pointed end is where it gets interesting, it's an exercise in localizing heat over a steep gradient on a short length. I've used water and a torch to control the twist. My vote is for the torch. That's it, I've had limited success and have never been really satisfied with the results but to be honest I didn't really stick with it more than a few attempts.

 

I'm just hoping someone here actually knows how to pull this off and will chime in and give us the straight poop.

 

Frosty The Lucky.

[Steve Sells]

the few I have made were as frosty stated, fullered and tapered square stock, then twisted,  They did not work well for me. I am excited and waiting to see a post about usable methods myself.

[Rich Hale]

In the blacksmithing section on this site,,,some time back there was a thread with video about forging a gun,,i think that is wot it was called,,,they forged all parts for a flintlock, one part was wood screws,,,that section was real short.It is about an hour video and worth watching. You may have to look a while to find it.

For wot its worth I have not seen a die that would cut the coarse threads for this type of screw....but there may be some out there.

[John B]

I know it doesn't answer your question, but an easy way is to forge weld the lag bolt onto the stock and work what you want on the new stock end.

[SmoothBore]

For what it's worth, ... and in my opinion only, ... It's NOT worth the bother.

 

I've had great success by drilling an undersize pilot hole, ... starting the thread in the wood by tapping the hole with a standard HSS tap of the correct size, ... and then just let the threaded bolt "form" it's own threads, as it's screwed in.

 

I've done this with 3/8" - 16 threads, into a 2x4 wall stud, ( to hold the ends of custom curtain rods ) ... right on up to 3/4"-10 threads, into a very hard, creosoted Telephone Pole. ( to carry a 12' farm gate )

 

Works like a charm.  :D

 

 

 

.

[Michael]

I've started with all sizes of lag bolts, removed the plating with a nice long citric acid soak and then forged the hooks, hangers and loops I need on the non threaded end.  As I understand it, points on screws (and lags, I'm assuming) are the way historians tell if screws (in say hinges) are machine or hand made.  Pointed screws indicate post 1840 machine made screws.

[bigfootnampa]

IMO it is a waste of time as a simple tapered nail shape will have equal strength... superior to store bought lags which are usually pretty brittle metal.  For J hooks and such the withdrawal forces are incredibly high!  If I want even more strength or maybe have only thin wood to attach to... I'll squirt a dab of super glue into the predrilled hole before driving the spike home... this is about as permanent as you can get... roughly equivalent to a dead nail!  In comparison to standard nails and screws from the hardware stores the only ones that are as reliable as my hand forged spikes are my hot-glue dipped, nail gun driven, ring shank nails... they must be cut to release the bonds... the forces required to remove them will destroy the wood!

[VaughnT]

I either buy lag bolts, cutting the heads off so I can forge the ends into a hook.....  Or, I buy the blanks from online retailers.  

 

Very easy way around having to cut and file threads into a blank!

[1forgeur]

The video Rich is referring to was "The Gunsmith of Williamsburg". It's on you tube. I think the thread was how to build a flintlock in an hour. Something like that anyway. Hope it helps.

[Rich Hale]

http://www.iforgeiron.com/topic/31425-making-a-rifle-in-58-minutes/

[Eddie Mullins]

Thanks guys. Video downloads are slow for me, but I'll try to watch it. But I'll also give the fuller and twist and file a try.

 

Like I said, I don't plan to do this often, just want the knowledge and experience. I also like to hunt and fish and cook outdoors and could see some potential uses of a removable hook or hanger I could screw into a tree without the need for a hammer or drill.

 

@bigfootnamp - I would have never thought to predrill and super glue for nails. I actually haven't even made a nail yet, a header is another item on my list to make.

[HWHII]

Last year I bid on a 18th century recreation hardware job. The client wanted lag bolt type pintles. Not sure what to do I called Peter Ross. He informed me that the lag screw was product of the industrial revolution and would not be period correct. He also stated that wood screws of the time would have been made on a lathe. In other words they are machine made not forged.