On Wednesday, January 26, 2022 at 7:01:04 PM UTC-8, Don Y wrote:> On 1/26/2022 6:16 PM, whit3rd wrote: > > On Tuesday, January 25, 2022 at 10:24:58 PM UTC-8, Don Y wrote: > >> I need a screw (a bit over 1/4" thread diameter) with a hole drilled > >> longitudinally throughout its length...> > Can you substitute a rivet with a hole in the middle? Those can be formed > > from tube in a variety of sizes and materials...> But, if one end of the rivet remains "blind", you need something to > grab it/bite into it. This then makes disassembly difficult when you > *want* to disassemble the item!Howabout drive rivets? The drive pin in the head expands the rivet's nether region, but could also be driven through and leave a hole, or with an overlength pin, could be driven and retracted... or even drive a hollow pin (perhaps with a driver that fills the hollow, for strength).
"Hollow" screw
Started by ●January 26, 2022
Reply by ●January 26, 20222022-01-26
Reply by ●January 27, 20222022-01-27
On 1/26/2022 8:54 PM, whit3rd wrote:> On Wednesday, January 26, 2022 at 7:01:04 PM UTC-8, Don Y wrote: >> On 1/26/2022 6:16 PM, whit3rd wrote: >>> On Tuesday, January 25, 2022 at 10:24:58 PM UTC-8, Don Y wrote: >>>> I need a screw (a bit over 1/4" thread diameter) with a hole drilled >>>> longitudinally throughout its length... > >>> Can you substitute a rivet with a hole in the middle? Those can be formed >>> from tube in a variety of sizes and materials... > >> But, if one end of the rivet remains "blind", you need something to >> grab it/bite into it. This then makes disassembly difficult when you >> *want* to disassemble the item! > > Howabout drive rivets?"Pop" rivets?> The drive pin in the head expands the rivet's nether > region, but could also be driven through and leave a hole, or with an overlength pin, > could be driven and retracted... or even drive a hollow pin (perhaps with > a driver that fills the hollow, for strength).I think the tool is intentionally designed to snap the drive pin off below the lip of the rivet, regardless of how long the pin *was*. I'm not sure if interposing a mechanical spacer between the tool and the lip of the rivet would result in the break point moving to remain close to the tool... or the rivet's lip! Driving the broken off part of the pin further in (to clear the hole) isn't always possible; there's "stuff" on the other side with which it would interfere. But, "bare" rivets -- chosen for length and secured "otherwise" may work. There are similar shaped COTS pieces that might also show promise <https://www.placediverter.com/wp-content/uploads/place_diverter_compression_fittings-1a.jpg> save for length (I'm trying to see how much shorter I can make these with a packaging rethink) The key revelation is not to think in terms of "screws" as that constrains your solution space unnecessarily!
Reply by ●January 27, 20222022-01-27
On Wednesday, January 26, 2022 at 11:47:20 PM UTC-8, Don Y wrote:> On 1/26/2022 8:54 PM, whit3rd wrote: > > On Wednesday, January 26, 2022 at 7:01:04 PM UTC-8, Don Y wrote:> >> But, if one end of the rivet remains "blind", you need something to > >> grab it/bite into it.> > How about drive rivets? > "Pop" rivets?No, not the apply-tension type, the apply-percussion type, that uses a pin protruding from the head that is struck with a hammer... <https://www.mcmaster.com/rivets/rivet-type~pin-drive/>> > The drive pin in the head expands the rivet's nether > > region, but could also be driven through and leave a hole, or with an overlength pin, > > could be driven and retracted... or even drive a hollow pin (perhaps with > > a driver that fills the hollow, for strength).
Reply by ●January 27, 20222022-01-27
On 1/27/2022 1:21 AM, whit3rd wrote:> On Wednesday, January 26, 2022 at 11:47:20 PM UTC-8, Don Y wrote: >> On 1/26/2022 8:54 PM, whit3rd wrote: >>> On Wednesday, January 26, 2022 at 7:01:04 PM UTC-8, Don Y wrote: > >>>> But, if one end of the rivet remains "blind", you need something to >>>> grab it/bite into it. > >>> How about drive rivets? >> "Pop" rivets? > > No, not the apply-tension type, the apply-percussion type, that uses > a pin protruding from the head that is struck with a hammer...But, presumably, the force required wouldn't *require* a hammer as the pin's motion is deforming the rivet in a manner simmilar to the "early tugs" on a pop rivet. The final -- higher force -- tug on the pop rivet is solely to snap the pin; the rivet has already been deformed (i.e., the pin could be left in place without affecting the quality of the fastening). Or, are the rivets made of tougher stuff that requires more force (e.g., hammer-struck)? I'm off to hardware store, today, for some spray paint. I will see if they have anything that I can evaluate. Thanks!> <https://www.mcmaster.com/rivets/rivet-type~pin-drive/> > >>> The drive pin in the head expands the rivet's nether >>> region, but could also be driven through and leave a hole, or with an overlength pin, >>> could be driven and retracted... or even drive a hollow pin (perhaps with >>> a driver that fills the hollow, for strength).
Reply by ●January 27, 20222022-01-27
On 1/26/2022 7:29 AM, Clive Arthur wrote:> 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.Ha! Who'd'a guessed?! Thankfully, I didn't find this before discovering other options else I would likely have "settled" for what appears to be a more expensive option. But, some of the offerings seem like they'd be handy to have on-hand just to compare to other approaches. All of the ebay hits seem 404. But, alibaba shows promise. Thanks!
Reply by ●January 27, 20222022-01-27
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Don Y wrote:> On 1/27/2022 1:21 AM, whit3rd wrote: >> On Wednesday, January 26, 2022 at 11:47:20 PM UTC-8, Don Y wrote: >>> On 1/26/2022 8:54 PM, whit3rd wrote: >>>> On Wednesday, January 26, 2022 at 7:01:04 PM UTC-8, Don Y wrote: >> >>>>> But, if one end of the rivet remains "blind", you need something to >>>>> grab it/bite into it. >> >>>> How about drive rivets? >>> "Pop" rivets? >> >> No, not the apply-tension type, the apply-percussion type, that uses >> a pin protruding from the head that is struck with a hammer... > > But, presumably, the force required wouldn't *require* a hammerYes, the "apply percussion" type of rivets require a hammer (and usually a form tool), and cannot be used in blind holes. Industrial[1] options are basically an unthreaded bolt which you stick through your piece. Then back the bolt with an anvil, and form the other end with a hammer (and likely a form tool). This is opposite to pop-rivets that we'd pick up from a hardware store where basically you have a pin with a sleeve around it. As you yank on the pin, you deform the sleeve. A simple (if labor intensive) approach for use around the home is tubes of whatever metal you please (aluminum, brass, copper, steel, whatever), a good sized bit of square steel, and a ball-peen hammer. (plus ancillary tools to hold / cut the long tube) - flare the end of the tube slightly with a few hits from the hammer (use the peen end ;) ) - cut the tube to sufficient length to fully pass through the parts to be joined, plus 0.062" to 0.125" (1/16 to 1/8) - stick tube through hole, with the initially flared end to the back (or less-accessible side), and hold it tight with your steel block - flare the front side (again, use the peen end) [1]Well, at least when "industry" used rivets. These days, welding is probably their goto. Loads of pictures available on the internet of steelworkers riveting buildings or ships or trains, etc. -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE3asj+xn6fYUcweBnbWVw5UznKGAFAmHyg/EACgkQbWVw5Uzn KGAhkA/7Bxskqpx93PymhuTv9TMZgXD9wMfQDW+hUx6stefYWcXcxlZy8kNqHQe3 LsxDBH88h5NgIqjHE0Nzu/s+LLaTEbWpM+tX9zSnmtcBYdpcSLTxBLrNLkCfuVMQ 9Z9WXfAnA33U60SxkLEG5+xe1BfY0HNU6M/Q6k6+CnaXKJhH4PZG8zkl+Of/VjiI 3TjE2PahnRGm/pu9qDza4ofdeQAtWxddIQpr22uL0pc58J8/Pa39gZ/Z47FCnW3l DFtVAkaYyon2eRHzmODGqcYbcmjyYQGR223GYURA9xVDsBIKnvDmMrcQOH+IDdBS rpoGyg7zf/2PHWM5LCRV9javR3i6L8HOYoaal8QuscneRBoPfvCN9dln6sxlqxvK +cmgyoQnnlxbuFIYjtnjRvq+wO8GEXwlcfV5ctqBcxFoK3OlsJYaQ2sbClykWXWP fSkZEgEde1hX/gcsCD+KKSGlx8xilMQKcu8r/SqXATz978BehXZuTF5ZvC6GrMf1 mLfyaIiZTtcy2e6niwQCR2vKF/hxr+AZIq48+2C5/ocry8YS7Ca2ZhGUS6zn33W5 7zv85JOY8AV3Evue8KFzJWgNUuGwME3VBWZ+aoZ0xJ5iBR9SKA19tYd4l/E+C6rb ZcHC+6DZpT0vJbxxee/x2N+bmvMbjZjQfMrj3Fv1V7nXJWXKZYU= =830r -----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 27, 20222022-01-27
On 1/26/2022 6:41 AM, legg wrote:> 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.That's an idea! I've not owned a bike in years so can't recall the details but I do recall their presence by the brake levers (effectively altering the ratio of inner cable to outer sheath)
Reply by ●January 27, 20222022-01-27
torsdag den 27. januar 2022 kl. 14.27.49 UTC+1 skrev Don Y:> On 1/27/2022 4:36 AM, Dan Purgert wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA512 > > > > Don Y wrote: > >> On 1/27/2022 1:21 AM, whit3rd wrote: > >>> On Wednesday, January 26, 2022 at 11:47:20 PM UTC-8, Don Y wrote: > >>>> On 1/26/2022 8:54 PM, whit3rd wrote: > >>>>> On Wednesday, January 26, 2022 at 7:01:04 PM UTC-8, Don Y wrote: > >>> > >>>>>> But, if one end of the rivet remains "blind", you need something to > >>>>>> grab it/bite into it. > >>> > >>>>> How about drive rivets? > >>>> "Pop" rivets? > >>> > >>> No, not the apply-tension type, the apply-percussion type, that uses > >>> a pin protruding from the head that is struck with a hammer... > >> > >> But, presumably, the force required wouldn't *require* a hammer > > > > Yes, the "apply percussion" type of rivets require a hammer (and usually > > a form tool), and cannot be used in blind holes. > The cited rivets appear to be "pop rivets in reverse". I.e., there is > a rod protruding from the *top* (formed) side of the rivet. As this > is pressed into the rivet body, the walls of the rivet are forced outward > in a manner similar (but different) to how the rod being *pulled* from > a pop rivet deforms THOSE walls. > > Contrast with a "regular" rivet that requires a swage to form the > yet-unformed end of the rivet. > > So, pressing (with sufficient force) on that pin will achieve the > same result as wacking it with a hammer. The question is: how > much force is required (cuz you are indirectly transferring that > force to the item into which the rivet is being installed!) > > Drive rivet: > <https://cdn11.bigcommerce.com/s-c7chaa/images/stencil/1280x1280/products/719/1859/drive_rivet__63707.1517517434.jpg?c=2&imbypass=on> > note the "split end", at right, that is inserted into the hole. > The protruding rod remains *inside* the rivet after fastening. > > Pop rivet: > <https://parts.pjtrailers.com/media/catalog/product/cache/1/image/1200x1200/9df78eab33525d08d6e5fb8d27136e95/1/8/180500b.jpg> > note the wide end, at left, that is drawn into the narrow body of the rivet. > The protruding rod is snapped off in the forming of the joint. > > Rivet: > <https://en.wikipedia.org/wiki/Rivet#/media/File:Rivet01.jpg> > note the absence of any "protruding rod/movable member" within the > rivet's body; the end must be peened over to bind. > > All of these leave you with an effectively "solid" rivet -- in that > there is no clear path through the rivet's body without some additional > labor step.you can get threaded pop rivets, once you have pulled the stem to set the rivet it doesn't snap, instead it unscrews leaving a threaded hole
Reply by ●January 27, 20222022-01-27
Le 26/01/2022 à 17:41, Lasse Langwadt Christensen a écrit :> onsdag den 26. januar 2022 kl. 10.48.31 UTC+1 skrev Don Y: >> On 1/26/2022 1:44 AM, Mikko OH2HVJ wrote: >> 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 >+1 It can even be used with hand tools. With care you can drill a hole almost twice as long as the drill bit. Try it
Reply by ●January 27, 20222022-01-27
Don Y <blockedofcourse@foo.invalid> wrote:> On 1/26/2022 1:44 AM, Mikko OH2HVJ wrote: >> Don Y <blockedofcourse@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)? > > And, I'd assume move from smaller diameter bits up through larger ones > to minimize the amount of material being removed with each. > > This has the added advantage of giving me prototypes with increasing > IDs that I can torque test (i.e., at what point have I removed > TOO MUCH material and lost strength?). Trying to do this with > ever smaller IDs means having to make (and destroy!) multiple screws > to test (until you find one "strong enough"). > >> Brass is easier to work with, but suitable drills work fine with steel, >> too.Why are you asking for help doing possibly the most simple task on a lathe, ever if you have all the expertise? You make everything overly complex and still end up with dumb solutions. It's fascinating. Drilling through the length of a fasterner, isn't hard. Drilling thtough even a 1/4-20 bolt can be done by hand with drill and pliers. It's not an engineering challenge. I used to drill through 12-24 screws all the time with just a hardware store drill bit and thread cutting oil.
