-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Don Y wrote:> On 1/26/2022 12:10 AM, Jasen Betts wrote: >> On 2022-01-26, Don Y <blockedofcourse@foo.invalid> wrote: >>> I need a screw (a bit over 1/4" thread diameter) with a hole >>> drilled longitudinally throughout its length. The hole as >>> large as feasible without significantly reducing the strength >>> to unusable (nebulous term) levels. >> >> braze or solder a nut onto a threaded tube. > > It's finding the threaded tube (of the right ID/OD) that is > the challenge. > >> OTOH parts like this are used in lighting, mechanical, and plumbing >> applications, perhaps you can get what you want off the shelf. > > The first thought was that of lamp rod. But, while claiming to be a > nominal "1/8 inch" diameter, the actual dimensions across the threads > are ~3/8". Far too fat for my needs. > ><https://www.amazon.com/Lamp-All-Thread-Pipe-Steel/dp/B008UWATVK>Yeah, that's because that "1/8 IP" is an "Iron Pipe" (or I think nowadays "International Pipe") dimension that defined the nominal inner diameter, not the outer. Note that a quick google indicates the actual ID is over a 1/4" on the rod you linked (way to go, 19th century naming conventions!) https://www.sizes.com/materials/pipe_Briggs.htm As far as I am aware, all pipe is still sold based on the (nominal) inner diameter, not the outer. Least this remnant of "half inch" copper pipe I have to hand is 0.625 (5/8) OD... -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE3asj+xn6fYUcweBnbWVw5UznKGAFAmHxJDEACgkQbWVw5Uzn KGBolxAAvCZYdev8MetY474AEjWxlp3frCjH3/RHHraJcbPtE+cORwUHT3b/JUl8 sHXrPEjzdHsgQnYy3h1JAbgmfzPunhtDl9qsbQZMkk0op1bQwt9dghWS1jDxoFBN rN2DssRkipE/Vzwh/XvatEBBaPLMrjjSlrv/RbWPq69lEFPICcl38L0XvHdOsxM3 bcbWZakPG5NMAhzNpE+dpx0/FafgwVgJmRwuZ3rpTqMTpVKiXBmhq/R0/DWapOXn Srh4Tpt1/ccfmf8TWu7eXMQsO2OFJDKbXrSps1Fozr/lzWKYijxHoea68iSVzPgi UpaTjuuomKRI0kcrrUM37nXTv6V5AkQXOVUW/wwkGHJazYydZ2GldoB12eO/3ZmS iPdJWZmLRMJQe7BLvGA1Jb5QEOS+nTFkdO9DxAzLSB1GpMBpoPMEAJ0u9vjmVAR0 lBFjHUrxx0JETR1oTefyMVYbK/3q46cVVZ92byC2SSlDabl2E8vItZeXRJetoAf5 pGznshsoT+Vgn3xEeHGmZGTko90KPoG6MOT5+m4r09zAwXpzYGqZrWfugXRN/60w uOKE+2Z4d0ECDyUibUvzVDQVxdGqDSCjNFVRHpBehzUQGUINAq3RlrTF19/K1Fi0 8Nzv3x09aR7Fi6XwRctHnzLFb9FhYuwrVI0V8QHV+/b7hPJD3ak= =x4LF -----END PGP SIGNATURE----- -- |_|O|_| Github: https://github.com/dpurgert |_|_|O| PGP: DDAB 23FB 19FA 7D85 1CC1 E067 6D65 70E5 4CE7 2860 |O|O|O|
"Hollow" screw
Started by ●January 26, 2022
Reply by ●January 26, 20222022-01-26
Reply by ●January 26, 20222022-01-26
On 1/26/2022 3:35 AM, Dan Purgert wrote:> -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA512 > > Don Y wrote: >> On 1/26/2022 12:10 AM, Jasen Betts wrote: >>> On 2022-01-26, Don Y <blockedofcourse@foo.invalid> wrote: >>>> I need a screw (a bit over 1/4" thread diameter) with a hole >>>> drilled longitudinally throughout its length. The hole as >>>> large as feasible without significantly reducing the strength >>>> to unusable (nebulous term) levels. >>> >>> braze or solder a nut onto a threaded tube. >> >> It's finding the threaded tube (of the right ID/OD) that is >> the challenge. >> >>> OTOH parts like this are used in lighting, mechanical, and plumbing >>> applications, perhaps you can get what you want off the shelf. >> >> The first thought was that of lamp rod. But, while claiming to be a >> nominal "1/8 inch" diameter, the actual dimensions across the threads >> are ~3/8". Far too fat for my needs. >> >> <https://www.amazon.com/Lamp-All-Thread-Pipe-Steel/dp/B008UWATVK> > > Yeah, that's because that "1/8 IP" is an "Iron Pipe" (or I think > nowadays "International Pipe") dimension that defined the nominal inner > diameter, not the outer. Note that a quick google indicates the actual > ID is over a 1/4" on the rod you linked (way to go, 19th century naming > conventions!)Exactly. Ever notice how *pots* (as in "flora") are sized? Or, other "dry measures"?> https://www.sizes.com/materials/pipe_Briggs.htm > > As far as I am aware, all pipe is still sold based on the (nominal) > inner diameter, not the outer. Least this remnant of "half inch" copper > pipe I have to hand is 0.625 (5/8) OD...But the outer diameter is the *controlled* dimension! The inner diameter is a consequence of the pipe schedule. So, all "1/8" pipe has the same OD (0.405) but differing IDs depending on wall thickness -- 0.035 to 0.095, in this case... a pretty big range! In my case, I'd prefer the OD to shrink based on schedule and hold ID constant. E.g., if the ID was *actually* 0.125 and I could use the thinnest wall pipe, I'd be in the 0.195 range for OD... Up to 0.315 with the thickest (which would be a tolerable ~5/16" instead of a fat ~3/8+) Or, specify the size based on the OD and let the ID vary. The current scheme is the worst of all worlds...
Reply by ●January 26, 20222022-01-26
On Tue, 25 Jan 2022 23:24:34 -0700, Don Y <blockedofcourse@foo.invalid> wrote:>I need a screw (a bit over 1/4" thread diameter) with a hole >drilled longitudinally throughout its length. The hole as >large as feasible without significantly reducing the strength >to unusable (nebulous term) levels. > >I realize I will eventually have to contract a casting or machined >parts. > >But, am looking for onesy-twosy quantities to demo a prototype. > >I thought I could approximate it using a threaded tube (NOT >a pipe nipple). But, getting premade threaded tubing in that >range seems difficult. > >I thought of manually threading a (soft, brass?) pipe of >suitable ID/OD. > >Also thought of having one *printed* -- but I'm not sure getting >the threads right would be practical (driven by how fine the >layers are?). (I think most *plastics* would be too brittle >when torqued in such an application so I'd have to print in >metal) > >I also thought of physically removing the core material from >a COTS screw (drill/cut -- possible with a brass screw?). > >Any other options?Look at bicycle caliper brake adjustment hardware. Thread OD typically 0.225in - possibly an M5 or M6 thread. RL
Reply by ●January 26, 20222022-01-26
On Tue, 25 Jan 2022 23:24:34 -0700, Don Y <blockedofcourse@foo.invalid> wrote:>I need a screw (a bit over 1/4" thread diameter) with a hole >drilled longitudinally throughout its length. The hole as >large as feasible without significantly reducing the strength >to unusable (nebulous term) levels. >Some 'Presta' inner tube stems also finish with hex head on the molded portion. .0.230in OD - possibly in plated brass. RL
Reply by ●January 26, 20222022-01-26
On 26/01/2022 06:24, Don Y wrote:> I need a screw (a bit over 1/4" thread diameter) with a hole > drilled longitudinally throughout its length. The hole as > large as feasible without significantly reducing the strength > to unusable (nebulous term) levels.<snip> 'Hollow screw' is a good search term. -- Cheers Clive
Reply by ●January 26, 20222022-01-26
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Don Y wrote:> On 1/26/2022 3:35 AM, Dan Purgert wrote: >> [...] >> As far as I am aware, all pipe is still sold based on the (nominal) >> inner diameter, not the outer. Least this remnant of "half inch" copper >> pipe I have to hand is 0.625 (5/8) OD... > > But the outer diameter is the *controlled* dimension! The inner diameter > is a consequence of the pipe schedule. So, all "1/8" pipe has the same OD > (0.405) but differing IDs depending on wall thickness -- 0.035 to 0.095, > in this case... a pretty big range! In my case, I'd prefer the OD to > shrink based on schedule and hold ID constant.Yeah, I'm just good enough with pipes to know "I need $size ID", and not really follow specifics past price at that point -- at least here, the thin copper ("Type M"?) is allowed in residential plumbing, so it's somewhat my go-to for repairs / rework. Although I do prefer the Type L in the kitchen and bathroom walls (they're exterior walls, so the thicker pipe makes me feel better, even if it is daft). -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE3asj+xn6fYUcweBnbWVw5UznKGAFAmHxXzIACgkQbWVw5Uzn KGDSpRAAnLaPXQ8RLncCJjeW58DmJluut+bRzldZ+tKpUnnJ3avOQMqIKVbeU7+x 6iuocvo5z0HVCjjf+mPfdFbUtIWLHsUO0Kv0/5upExtyTluv5Gf1Xy/18wHyGs9p 8PiCpf3U8YxQ5MqsA5B5Z7rOJ9VzLckz2W1AeO1cBLsRSlSJFsyPBssMxiO89fvy +14BE3iMWKhN0TUD/NmGZkRhKGDXf+xpCwB3cyBVqGAaLZ4Kbr5KEKFzQ7YWxBmE FZriq8MKSOksbHadZLIF6Yh03MHIxKsOPFCBgo2FEYAM+jYsnXyob0vVa41ELfuM uL67xw4uX+RNQEM0np9PJv1a3yFpHjq7TE5vRvU+CCymFrbZxi4SW+KDecyDEtqr 1Rzu+i8JUjFtpfPSsg8t0LPOnAbERVzrTgvjWHLS3hRMtjuZxH9BFneU+ccBySDH kiYjuLvrWSGKnQwLC0fpWW9xXSDxh2ZJUQpDfpPk/5fF1mjzdVsmewUj5I97UrJY CX7V3TpSYaPp3GeXODxJhTqowD033dojvgie+K+IR7nVy+cQvyv7tCdGJIoJzkip 2x6hLj/VnirHjzhoMWy12ceY6Z55Pvou9jofRuJvffD4UBtprDc3pF1po6WnR6gW ctIydonN258pJBhkNjeZMcbfdsKpH5Sy3xeMNGOldPoXnRdNZEw= =ubQi -----END PGP SIGNATURE----- -- |_|O|_| Github: https://github.com/dpurgert |_|_|O| PGP: DDAB 23FB 19FA 7D85 1CC1 E067 6D65 70E5 4CE7 2860 |O|O|O|
Reply by ●January 26, 20222022-01-26
Don Y wrote:> I need a screw (a bit over 1/4" thread diameter) with a hole > drilled longitudinally throughout its length. The hole as > large as feasible without significantly reducing the strength > to unusable (nebulous term) levels. > > I realize I will eventually have to contract a casting or machined > parts. > > But, am looking for onesy-twosy quantities to demo a prototype. > > I thought I could approximate it using a threaded tube (NOT > a pipe nipple). But, getting premade threaded tubing in that > range seems difficult. > > I thought of manually threading a (soft, brass?) pipe of > suitable ID/OD. > > Also thought of having one *printed* -- but I'm not sure getting > the threads right would be practical (driven by how fine the > layers are?). (I think most *plastics* would be too brittle > when torqued in such an application so I'd have to print in > metal) > > I also thought of physically removing the core material from > a COTS screw (drill/cut -- possible with a brass screw?). > > Any other options?You could always just cut a slot in the screw with a Dremel. If you need something better than that, you can get "vented screws" from Mcmaster Carr. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●January 26, 20222022-01-26
On Tue, 25 Jan 2022 23:24:34 -0700, Don Y wrote:> I need a screw (a bit over 1/4" thread diameter) with a hole drilled > longitudinally throughout its length. The hole as large as feasible > without significantly reducing the strength to unusable (nebulous term) > levels. > > I realize I will eventually have to contract a casting or machined > parts. > > But, am looking for onesy-twosy quantities to demo a prototype. > > I thought I could approximate it using a threaded tube (NOT a pipe > nipple). But, getting premade threaded tubing in that range seems > difficult. > > I thought of manually threading a (soft, brass?) pipe of suitable ID/OD. > > Also thought of having one *printed* -- but I'm not sure getting the > threads right would be practical (driven by how fine the layers are?). > (I think most *plastics* would be too brittle when torqued in such an > application so I'd have to print in metal) > > I also thought of physically removing the core material from a COTS > screw (drill/cut -- possible with a brass screw?). > > Any other options?. You can buy a blister pak of screws made to hang things on drywall; they're white plastic, about 5/16" diameter, 2"long, flat head, sharp point,very coarse thread. Maybe you could drill 'em.
Reply by ●January 26, 20222022-01-26
onsdag den 26. januar 2022 kl. 10.48.31 UTC+1 skrev Don Y:> On 1/26/2022 1:44 AM, Mikko OH2HVJ wrote: > > Don Y <blocked...@foo.invalid> writes: > > > >> I need a screw (a bit over 1/4" thread diameter) with a hole > >> drilled longitudinally throughout its length. The hole as > >> large as feasible without significantly reducing the strength > >> to unusable (nebulous term) levels. > > > > Drill a hole to the screw ? If you don't have a lathe, you can do this > > with a drill press by fixing the screw to the chuck and having the drill > > bit stationary. Drill a starting hole with larger drill and through with > > a smaller one(s). > ? > > Why wouldn't I thread the screw into a tapped block (to support and > reinforce the threads -- as well as act as a heat sink) -- after coating > it with antiseize (as the drill bit's rotation will tend to want > to tighten the screw in the block, possibly making removal more > difficult)?because it is much easier to keep the drill centered by spinning the part instead of the drill, try it .. https://youtu.be/v5yx1C-maRo
Reply by ●January 26, 20222022-01-26
On 1/26/2022 8:24, Don Y wrote:> I need a screw (a bit over 1/4" thread diameter) with a hole > drilled longitudinally throughout its length. The hole as > large as feasible without significantly reducing the strength > to unusable (nebulous term) levels. > > I realize I will eventually have to contract a casting or machined > parts. > > But, am looking for onesy-twosy quantities to demo a prototype. > > I thought I could approximate it using a threaded tube (NOT > a pipe nipple). But, getting premade threaded tubing in that > range seems difficult. > > I thought of manually threading a (soft, brass?) pipe of > suitable ID/OD. > > Also thought of having one *printed* -- but I'm not sure getting > the threads right would be practical (driven by how fine the > layers are?). (I think most *plastics* would be too brittle > when torqued in such an application so I'd have to print in > metal) > > I also thought of physically removing the core material from > a COTS screw (drill/cut -- possible with a brass screw?). > > Any other options?How long do you need it to be? If within reason (< say 50mm) and if you were living in the neighbourhood I could have made it for you... Well not 1/4", M6 but I suppose you'll live with that. A 4mm hole would be OK I think. I have some supply of 8mm brass...
