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List of screw drives

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Re: List of screw drives

#251

Post by ddacunha »

joncrane wrote: post #204

Interesting historical point: Apple started using the pentalobe fasteners in their iPhones in order to make it more difficult for end users to service their phones. https://www.ifixit.com/blog/2011/01/20/apples-diabolical-pla...

Is this the reason they have switched to Pentalobe screw. I have googled for material but couldn't find anything. Pentalobe screws are not that hard to find and considering the popularity of Apple devices, they will get easier to find. When I compare them to Torx screws I suppose the points rounder shape makes the screwdriver more resistant, which may be an advantage when assembly millions. I am no expert, and I would appreciate if someone has an informed opinion.

Re: List of screw drives

#252

Post by thunfischbrot »

vertexFarm wrote: post #186
Lionsion wrote: post #175

Important FYI for any Americans who don't know: Ikea screws are not Phillips, they're actually Pozidriv , which is different enough to matter. Do not use a Phillips screwdriver to assemble Ikea furnature, as that combination will easily cam out and ruin the (typically soft metal) screw. It's easiest to buy the correct Pozidriv screwdriver bits from Ikea, but they're also available online. My understanding is that Poz…

Ugh, except Pozidriv will still cam and tear up their own screws, and same with Phillips. That's the secret to this tidbit of information that is never included. They're both trash fasteners when used with a slightly different driver, but they're also trash even when used correctly. Robertson for life. When I was young I had a job assembling furniture and that, along with a couple Allen socket fasteners, was the only…

While I generally agree that neither are great (I prefer Torx), are they not designed to protect whatever it is you are fastening from over-tightening bolts?

Re: List of screw drives

#253

Post by jammi »

germinalphrase wrote: post #208
jammi wrote: post #88

Earlier quoted context omitted.

Yes, if maintained properly, which means swapping out these engineered to fail parts every so often, which becomes uneconomical at least in the resale sense at some point in time, because the repaired car resale value is less than the cost of repair. For instance on VAG cars, the designed to fail cash-cow parts are typically the various suspension bushings. Once such a part is worn out, resulting in a part that has e…

And advice on identifying such cash-cow parts? My vehicle repair knowledge is limited.

Experience first-hand or via experts who repair them daily, the former can be done by owning the same car or brand for a longer while and spotting the pattern.

Prefer makes that have excellent rust protection and models with relatively low stress configuration engines rather than high performance models. The two latter are usually mechanically the same or mostly the same, but the latter of them receive much larger stresses in use and hence tend to fail earlier.

If you intend to modify the car, prefer older ones, because they have lower regulations, but this depends on the legislative area you are in as well. For instance cars with OBD-II are too new for engine upgrades almost anywhere.

Re: List of screw drives

#254

Post by joncrane »

ddacunha wrote: post #251
joncrane wrote: post #204

Interesting historical point: Apple started using the pentalobe fasteners in their iPhones in order to make it more difficult for end users to service their phones. https://www.ifixit.com/blog/2011/01/20/apples-diabolical-pla...

Is this the reason they have switched to Pentalobe screw. I have googled for material but couldn't find anything. Pentalobe screws are not that hard to find and considering the popularity of Apple devices, they will get easier to find. When I compare them to Torx screws I suppose the points rounder shape makes the screwdriver more resistant, which may be an advantage when assembly millions. I am no expert, and I woul…

Well, let's try the counterargument approach.

Given what we know about fasteners (you need look no further than this thread), why else would Apple choose Pentalobe, of all the options?

Re: List of screw drives

#255

Post by [deleted] »

TeMPOraL wrote: post #247
kazinator wrote: post #240

Earlier quoted context omitted.

US shoe numbering for men is simple. There is a bit of insanity in that women's and children's sizes are derived from that in more than one way. There are two ways of determining size, but they are supposed to coincide, theoretically. Manufacturers use the "last length" as the basis for shoe size. However, that is not the foot length, and how a shoe with a given "last length" fits a given foot is a variable and so th…

Yeah, I meant "foot centimeters" - the issue isn't about metric vs. imperial, I'm just writing from European experience. The issue is about "foot" vs "last" vs "shoe numbers". I'm not fully convinced by the argument that manufacturers (or at least distributors) can't use foot centimeters - after all, somehow I can successfully buy shoes on-line by measuring my foot and then using vendor-provided foot-length-to-shoe-s…

[deleted]

Re: List of screw drives

#256

Post by bluGill »

dmurray wrote: post #238
bluGill wrote: post #157

Earlier quoted context omitted.

No it isn't equivalent to all other pipes in terms of capacity and robustness. It is equivalent to the COMMON pipe today, but you still have to watch because some applications use the same thread/outside diameter but the walls are thicker. Also there are still some old pipes out there that really do have the 1/2 inch inside diameter, they are equivalent in terms of robustness, but obviously not capacity. Of course I'…

Is it correct to say it's equivalent or better than the "standard" half inch pipe in all three of: inside diameter (larger is better), outside diameter (smaller is better) and robustness? With the "standard" half inch pipe actually being an old type that is now obsolete?

Being pedantic again, there are cases where more inside diameter is not better. Some chemicals are unstable and dangerous when concentrated into too much volume: by increasing the inside diameter you make them more likely to explode. (acetylene - C2H2 - is the only one I can think of where this could matter). On the same lines, if the pipe is subject to heat/flame there is another case where modern metals might be worse by allowing thinner walls.

Again, this is only pedantic. In the unlikely event that the above matters you need a professional engineer (a legal term) to specify the exact properties of the pipe.

Re: List of screw drives

#257

Post by heavenlyblue »

kbrosnan wrote: post #79
micheljansen wrote: post #75

Earlier quoted context omitted.

As someone who has just remodelled an old house with loads of flatheads: you've got to be kidding me. I hate those things with a passion. Flathead screws only restrict the movement of the screwdriver in one dimension and allow it to move in the other one. This leads to the screwdriver to keep sliding out when you put force on under even the slightest angle. Phillips screws improve on this design by restricting moveme…

An advantage of flathead is that it is easy to unfoul the screw head. A minute with a utility knife or a flathead screwdriver will clear the channel of dirt or paint. I would not want to deal with a torx that has several layers of paint dried into it.

Use a needle or a knife.

Re: List of screw drives

#258

Post by flamtap »

grmarcil wrote: post #233
simonbarker87 wrote: post #214

Earlier quoted context omitted.

Yeah I’m in the UK, ok so probably as rare as square heads here then.

Interesting, I did not realize square drive was uncommon in the UK. It's a really nice screw head to work with, and as someone mentioned elsewhere in the thread, becoming more common in certain woodworking applications in the US.

It's a Canadian invention, and to this day quite localized to Canada, where it's nearly the standard for carpentry (at least, every deck screw I've ever seen here is Robertson drive). It's good that it's catching on, it has a few distinct advantages over Phillips, my favourite being that you can mount a screw on the driver and it will stay on the driver due to an interference fit, freeing your other hand to secure, support, or stabilize.

Re: List of screw drives

#259

Post by mindslight »

vertexFarm wrote: post #244
antisthenes wrote: post #219

Earlier quoted context omitted.

Last time I tried to use a Robertson screw from Home Depot in a heavy duty application (building an AC frame and decking), it cammed out and the square opening in the screw literally became round. I tried compensating by applying more downward force, but eventually it was still camming out and the bit itself became a cylinder. It maybe better, but if the manufacturing quality is garbage, it's just as useless as the o…

Huh. I've never had that happen once out of literally thousands of screws from all kinds of different sources, including HD. Should be impossible for it to cam because the walls of the cavity are perpendicular. There's no thrust force being generated. Maybe it was just a really bad batch?

I have some R2 stainless "decking" (read: general construction) screws, and a standard consumer cordless impact driver generates enough transient torque to actually deform the cavity. Which even then results in the bit being "sticky" to pull out. I would imagine after several use cycles, the drive would be completely stripped.

Re: List of screw drives

#260

Post by mindslight »

pasbesoin wrote: post #236
mattmillr wrote: post #196

Earlier quoted context omitted.

Ikea sells a $8 tool set that includes three sizes of Pozidriv bits - and other bits that perfectly fit their various connectors. It's well worth the cost if you're planning to assemble anything you got from IKEA and not lose your mind.

They also have, or had, a circa $25 corded drill kit for sale (going by memory of briefly seeing, a year or two ago). If someone doesn't have a drill and is contemplating purchasing and constructing a substantial piece of IKEA furniture, such as my parent's TV stand -- lots of bits to screw together. Under those circumstances, I suggest maybe they want to buy one of the drill kits. I expect you can get a better corde…

IMHO if you're getting something for infrequent use, avoid batteries as they'll just go bad when sitting around unused.
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