Thread: A wooden thread thread
8th Mar 2018, 08:42 PM #16SENIOR MEMBER
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- Buderim qld
Ian, I looked at the video and I am curious to know the type of router bit you were using. Will have to have a re-look at the video as I did not quite understand how you got the threads to cut at an even rate/space as you pushed the blank in.
.....and what do you consider the most versatile thread size ie., 1" 1.25" or 1.5"?
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8th Mar 2018, 10:30 PM #17
they're in the section with the Beall threading kits. Don't know if you can get the same bit locally, but there are alternatives. The carbide bit suits me because I do a lot of threading, but a re-purposed HSS drill bit will easily cut a few bench screws for you.
You must've missed the crucial part - the threading jig consists of two parts. There is a pilot hole the full diameter of the screw in the front piece, matched to a concentric threaded hole in the back piece. There is a hole cut out of the bottom, between the two halves of the jig so that the bit can be set just in front of the first thread. As the bit starts to cut your blank, you just twist it & the thread pulls the blank in at the correct pitch, cutting the thread as you go.
The bloke in this thread I linked to uses the same sort of 'primitive' tap I demonstrated, but cuts his screw threads differently. Instead of using a nut made with his tap to make the threading jig, he uses the tap itself to drive the blank past the router bit, with a captive plate riding in the kerf on the tap, the same as when tapping a nut with it. I think the jig I show is easier to make & set up, and whereas the length you can thread is unlimited with 'my' system, you are limited to the length of the tap shank with his.
What size is most versatile? Depends entirely on what you want. If you want bench screws, 2" is probably the best. I do use 1.5" quite a bit for smaller vises like a "moxon" vise. For handscrews, 3/4" is probably the most useful size, unless you are a luthier, in which case 1/2" might be the better choice. I have & use all sizes from 3/8th to 2.5"......
8th Mar 2018, 11:42 PM #18
I still haven't had the chance to read through this thread yet . looking forward to it
This is all I can add .
Here is what myself and a friend repaired a week ago . A Mahogany dressing table Arm that holds one side of the mirror and which is screwed to its base with a 5/8 wooden thread. The original nut was lost . Comparing measurements and pitch , we didnt have a tap the right size to re make a nut only. But we had a tap and die for a similar close size . So we made up some dowel out of Sassafras , some boards I bought of a guy who delivers wood by schooner from Tassie across Bass Straight to the local port 10 K from me. First time Ive bought wood like that ! And I soaked it in Paraffin oil for a short time . Im not sure it really needed it . It cut so perfectly and was very well behaved . It was very enjoyable seeing it going in one side and coming out the other. Tapping some nuts was easy as well .Thats the new thread and nut in the right picture, some extra lengths were cut as well , seen in between the arms .
This is the type of tool that cut it . Sarjents from the UK
And some info on them that is interesting .
I have a few cutters including two of the German type, the largest which cut my Red Gum bench thread that Ian Mentioned . The Red Gum cut great and as Ian said is going great after all this time .its a 62mm thread.
I cant see any bad obvious wear , just some damage from dropping tools on it or touching with a saw maybe ? That's just in the most exposed first 100 mm . You can see beyond that its just burnished Red Gum
Ive got another bench here that I am storing for an friend . He cut the thread by sight, hand saw and chisel. its Blackwood. The method where the turning is wrapped in tape . Ill get a picture when I can .
9th Mar 2018, 09:49 AM #19
Glad you brought up cutting screw threads by eye, I forgot to mention that as an even more 'primitive' alternative. FWW featured an old bloke once, who not only cut pretty neat-looking screws with a saw & carving tools, he made the nuts as well. How? He cut the nut in half, then carved the threads with a V-tool, then glued them back together. He was using a vise he'd made a long time back to hold the work for his demo, so it obviously worked!
Sometimes you have to get creative when faced with replacing a broken threaded part on an old piece.There was absolutely no standardisation of wooden threads & I've seen all manner of tpis & thread angles, though 90* seems to be the most common on old European & British stuff. Early on in my wood-threading career, I picked up this Rosewood plough. pic4.jpg pic1.jpg
It looked terminal when I got it, it had been left out in the rain, and had turned a uniform grey colour, no blades or wedge, of course. One of the threaded fence arms was stripped, the other was chipped quite a bit but usable, and all of the nuts were missing, bar one which was badly split. The threaded arms are about 7/8" diameter and roughly 6tpi. I could not find, beg, borrow or steal a tap or threadbox that would match, so it had me stumped for a while. There were about 6 turns of relatively intact thread left on the end of the busted arm, which gave me a whacky idea. I tapered these off a bit & drove a bunch of screws into the threads in a spiral pattern, then filed them off to make cutters & scooped out a bit of wood in front of each to hold chips. Amazingly, it worked, & I was able to tap new nuts and make a jig for the router & thread a new arm. I managed to get some Rosewood for the new arm & a wedge, but couldn't get any thick enough to make new nuts, so I went for the contrast of some Boxwood instead. A few doses of thinned Danish oil revived the colour, & over the years I've managed to acquire a pretty full set of cutters, so I have a decent working plough that almost ended its days in landfill!
It looks like the thread angle on the tap Rob used to repair the mirror above is 90*. I assume this angle was chosen to maximise buttressing of those cross-grain threads. Because I started with a 60* tap, I've gone along with that thread angle on all of the taps I've made or had made for me. I do have 90* threads on some bar clamps that I made using a borrowed tap, but I haven't noticed any difference in durability compared with my 60* versions. It probably depends on the wood - in the northern hemisphere they tend to use softer woods than the species I like to use.
Chipping of threads from accidents is a hazard, but I haven't had too many problems from that source over the years. I'm reasonably careful, but working tools have to take their licks. I didn't use a wooden screw on my front vise, and the tail vise screw is well protected - it still looks pristine after 30 plus years in use. Severe chipping can happen when threading if you use dull cutters, or the cutter isn't properly aligned with the thread, or because of unseen splits & flaws in your screw blanks. Moderate chipping doesn't seem to have any effect on action or strength, but it looks fugly, so any manky threads I produce go straight to the fire-starter pile......
9th Mar 2018, 02:18 PM #20
Nice Plow and save Ian!
I have had dreams about owning a BRW plow and that's as close as I got to having one.
I used to see a few in the Tony Murland tool auction Catalogues in the UK but the price put me off .
Yours was left out in the rain!! Before you rescued it .
9th Mar 2018, 07:32 PM #21
The thinned-down Danish closed up the end-checks, they've disappeared completely, but I couldn't clean the skate back to shiny metal, the pits were too deep, so it has to wear those scars. Some day I'd like to find some bits of Rosewood so I can make locking nuts like the originals. Genuine BRW is out of the question, but one of the other Dalbergias might be close enough to pass if you didn't inspect it too closely...
11th Mar 2018, 03:27 PM #22
Auscab, that monster 62mm threader looks expensive! Shame to have it hidden away.
11th Mar 2018, 08:23 PM #23
Now if I had the whole set !! that'd be nice ! Have them all fitted up in felt lined drawers.
Have a look at the pricing though.
If I won lotto or something ? I didn't pay that . I got it third hand at least.
I did get these yesterday at an auction in Adelaide.
I don't have them yet . I don't have a clue as to the sizes but some look like 1/2 to 5/8 and larger.
hopefully they are in reasonable condition .
12th Mar 2018, 09:14 AM #24
If you are going to use them daily as part of earning your living, get the best for sure, but for a tool that most would use very occasionally, or just a few times, it would be hard to justify that sort of outlay. The threadbox sets sold by Carbatec et al. won't match those for quality, but let's be honest, most folks are probably going to quit threading after they make a few sets of handscrews or a bench screw or three, so it is probably wise to keep your outlay modest. You'll cut all the threads you are likely to need with the cheaper alternatives (as long as you can find suitable threading wood).
As I said, if you own a router already, you could set yourself up for making the large-sized screws for zero cost, at any tpi or thread angle you desire. It takes a few minutes more to tap a nut with the 'primitive' multiple-pass system, but the actual amount of time it takes is trivial compared with building the rest of the bench....
12th Mar 2018, 09:45 AM #25
12th Mar 2018, 11:15 AM #26
12th Mar 2018, 04:18 PM #27
Here is the hand cut Blackwood bench thread . 62 mm as well Iím pretty sure .Itís nut was hand cut and split in two . Screwed back together after that . The thread is solid and you can see the larger end has been laminated . The bench was made over ten years ago and hasnít been finished or stored to well . Itís been kept under lean to shelter so has been effected by weather . The laminations have moved . Itís a pretty good tight working thread still . Itíll be nice if the guy finishes it . The vice is Blackwood but the rest is vic ash with a Blackwood stain .
15th Apr 2018, 11:36 AM #28
15th Apr 2018, 02:20 PM #29
That looks like a good range of sizes and a good acquisition. When you get the time it will be interesting to count the numbers of threads to the inch particularly in the smaller diameters where timber has trouble maintaining a tight thread. They seem to be quite coarse, which would be good.
"Power tends to corrupt. Absolute power corrupts, absolutely!"
9th Aug 2018, 01:02 PM #30Member
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- Jul 2018
I am interested in wooden threads. I am planning on making my next bench to be completely devoid of purchased hardware, and using home made wooden threads instead, most likely for a shoulder vice and a tail vice, so I will probably need 2 thread different diameters & pitches
It occurs to me that there is no complete explanation of how to make the tap, from scratch, so I thought I'd run "the plan" by you before I start.
If I were to make the tap, I presume I start by making a round blank, of an appropriate diameter. I think I'd need to rotate square(ish) stock in some sort of a collar in proximity to a router bit in a holder jig. The entry to the collar would be a hole corresponding to the diagonal of the feed stock, the exit would be a hole corresponding to the required blank's diameter, and the router bit would sit above/below somewhere in the middle.
Once the feed stock for making the tap was finished... To get the kerf layout, I'd wrap a rope coil around the blank (varying the diameter of the rope to vary the pitch as required eg. 10mm should give 2.5 TPI whereas 4mm rope ==> 6.35TPI), and then either mark the gap between the coils to get the "set out" to cut later (It seems a hacksaw blade would be appropriate to do the marking), or perhaps use the rope to both turn and advance the blank at the correct pitch over a cutter of some sort (perhaps a trim router or a dremel with a small bit in another simple holder jig). The entry hole to the jig would need to be tight enough to keep the drive rope out of the jig during rotation, which should be pretty easy, perhaps with a steel eye loop to keep the exit point consistently at the same spot on the entry side of the jig.
Does this seem on the right track for a reasonable, cheap approach?
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