I had a look at it. My father is happy for me to attempt to fix it, as long as I don't do anything irreversible. It looks like the head of the cap screw protrudes by about 1/32", whereas it should be flush or below flush. I think the screw is either 1/4" or 5/16" BSW, which will not be an easy size to get. First I think I will remove the screw and see if there is anything underneath it. It is odd as I thought that the height of cap screw heads were mostly standard.
No, nothing rotates. The scale is a sticker and the pointer is a piece of steel plate crimped onto a length of threaded rod. It's not a great drill press. I am hoping to get another soon. I thought about getting an Arboga drill a while back, but then decided not in case I got a mill, because that would make it redundant.
I had another idea. The problem with the scale on the drill press at the moment is that you can't look at the scale and the piece of work at the same time. So I thought for now I might just wrap a piece of coloured tape around the drill. It would at least be directly in my field of view, even if it isn't a hard stop.
The problem I find with cheap screwdrivers is that they wear quickly, and sometimes the tip becomes twisted. I have a cheap Stanley flat screwdriver I bought a while back (it was not one of their most expensive ones) and the blade distorted in normal use. If I'm going to spend time carefully modifying a screwdriver, I don't want to find that it rapidly becomes unusable because of the quality of the material. My experience has been that cheap screwdrivers are mostly a nuisance.
This did occur to me. It also occurred to me that if I could get 1/4" hexagonal drill rod, this would allow me to make screwdriver bits without needing to make a handle. But I couldn't find any.
I think in this case you're right. I do have a preference for fixed blade screwdrivers when they're available, though. Interchangeable bits aren't always held tightly in the handle, and the handle is usually a bit bulkier.
I had wondered about buying interchangeable bits and attempting to modify them using a half round file, but I'm not sure if they could readily be filed.
True enough. I wish the makers of the best screwdrivers would make a wider range of tip sizes.
These are the ones I have:
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Yes, they have a larger hexagonal section below the handle for this purpose in addition to the hexagonal shaft. Also, the shaft goes right the way through the plastic handle and emerges as a metal cap.
I just had a look at knurling tools. Good ones are relatively expensive. A good one looks to be a similar price to that Brownells screwdriver set, even including the postage.
I think I am coming round to the idea of the Brownells set. It would get a lot of use. They don't say much about the type of steel they're made from, though. Some, but not all, screwdrivers advertise "Cr-V" or "Cr-V-Mo".
You might find it easier to grind the blade thin on a sanding drum or the roller of a belt sander. They will give you a hollow grind of smaller radius than a bench grinding wheel.
Gunner, I checked out their website and that is a nice looking kit. It looks more appropriate for me than the Brownells kit as there are no
0.020" bits in it. On the equipment I work on, I doubt I would have a use for the 0.020" bits, and they make up half of the Brownells kit. Why someone ever made a screw with a 0.360" by 0.020" slot (one of the sizes in the Brownells kit) is beyond me.
I discovered today that I also need a 1/4" x 0.025" bit, as opposed to just the 3/16" by 0.025" bit, so a kit is looking like a good option.
The price of that Chapman kit is right too. I've already e-mailed them to ask what shipping the kit to England would cost. The reviews on Amazon are favourable, and with Gunner's blessing I'm assuming there aren't any quality issues with these kits. But if anyone thinks otherwise, now's the time to let me know.
Right. But any metalworking shop should have some Casenit on hand. I use it frequently for all sorts of things. Lately I've made some custom hole saws with it, for trepanning wood on the butt end of a fly rod.
I've heard that those commercial case-hardening compounds are not allowed for sale in the UK. Is that correct?
Is it possible that the original screw was a slotted head screw instead -- and someone replaced it with the BSW? Or perhaps the threads in the hole had been stripped out and it was drilled larger and tapped for the next size up -- which would of course have a larger head.
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Oh -- that design. The threaded rod is attached to the quill and moves downward with it? Does it move through a hole or a slot in a projection from the main casting? If so -- then a depth stop is as simple as placing a pair of nuts onto the threaded rod, spinning them down so they touch the projection when the drill bit is at the right depth, and tightening the two nuts together so they don't vibrate and change their setting.
And that pointer was probably originally a bent piece of steel producing two holes for the rod to pass through and capturing between them a knurled OD nut to allow the pointer to be moved up and down as needed. There should be a spring to keep the knurled OD nut from rotating except when you *want* to rotate it -- and perhaps even an arrangement so when you press a tab the threads disengage to allow quick motion of the stop.
This is the old way to serve as a depth stop -- present on many quality drill presses. I suspect that the head casting is split at the bottom and there is a bent lever which will tighten it around the quill so you can lock the quill in an extended position as well.
It may be better than you think -- just missing some parts. Can you post a close-up of the head part -- especially the threaded rod? (You can either put them on your own web space, or submit them to the dropbox
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and then post the resulting URL here for us to follow and look at it.
Yes -- that can work. I've done similar things around a boring bar when boring a hole with a bottom instead of a through hole -- and when threading the ID of a hole as well.
Of course -- but a cheap screwdriver to modify to make a one-time use screwdriver is often quite sufficient.
*One-time* use. If you expect to use it a lot, you start with good materials.
Sure you can. Someone else already posted the source. Allen keys (1/4" size, obviously). Cut off the elbow, and you have a short piece and a longer piece. And they are normally good steel. You can also buy a single size in boxes of 100 or 144 (depending on the size) for a quite affordable price.
In the MSC catalog, for example, I find:
====================================================================== Hex & Torx Keys, Drivers, & Sets Tool Type: Hex End Key Fastener Type: Standard Hex Measurement Type: Inch Handle Type: L-Key Short Arm Hex Size: 1/4 Material: Alloy Steel ======================================================================
And the price for a box of 100 made by Eklind is $45.28 (Probably about
22 UKP these days.)
The same general description, but
Import $31.16 Allen $57.45 Bondhus $42.32
But -- the interchangeable bits allow me to use them in a electric screwdriver with adjustable torque limit. For some things, a manual screwdriver is about as good, but when dealing with (for example) changing out a set of cards in an old Sun 4/370 computer (3U VME bus), you have two Allen head screws, M3x0.45 with about 1" of thread to back out for each card -- and about 12 cards total in the system. And you can get sets of hex shank screwdriver bits with all kinds of special security tips as well as the standard slotted, Phillips, Allen and Torx. Examples are the Offset Phillips (standard four blades, but offset from the center so they tighten more firmly, and so they intentionally walk out when you try to remove the screw, Tri-Wing (same as above, but only three blades), Security Allen (hole in the center of the bit to clear a pin in the screw head), Security Torx (similar to the Allen), split-point straight blades, and various other weird types -- all with
1/4" shanks, so they can fit either the manual screwdriver handles or the electric driver (which has the added benefit of an adjustable torque limit so you won't strip out screws in mild stamped steel).
The electric screwdriver which I use was originally made by AEG, and more recently Panasonic and Milwaukee -- same screwdriver, different color plastic. :-)
If not, they can be ground.
I think that the makers of the best screwdrivers are targeting screws with the proper thickness slot for the width of the blade. The torque required is defined by the diameter and thread pitch. This defines the size of the head, and this the width and thickness of the slot to have sufficient strength to handle these without bending.
Your narrow slotted screws are not really properly designed. They were made with the size of slotting saw which the maker had on hand -- and he did not want to buy a bunch of other thicknesses.
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O.K. *Quite* colorful, and too large to fit my belt pouch (which has my checkbook, several sizes of small screwdrivers, pens, calculators, and usually a small pin vise all there on my belt).
Hmm ... that latter feature is a design to survive abuse by hammering on the end of the driver.
Yes -- but you can then be equipped to make other tools using it.
And some which advertise that are still poorly hardened and tempered -- either too soft, or too brittle.
I apologise for taking a while to get back to you.
I think there are two possibilities. The first it that the head of the screw is of the wrong dimensions. The second is that there's something stuck under the head, perhaps a washer or even some swarf. I don't think that the hole has been damaged and re-tapped. There is no evidence the the screw is larger than would be expected, and to be honest it's very difficult to see how it alone would have got damaged, given its location. I am pretty sure that the screw would break before stripping the thread, given the length of the thread. With a 5/16" screw this would take a lot of force, and there is no sign of damage anywhere on the lathe.
I suppose it's conceivable that someone has replaced the BSW screw with a UNC screw with different head dimensions, as the two standards sometimes have matching diameters and pitches, even though the thread angles are different.
I don't think I will know until I get chance to take it out. If I have a chance this weekend, I will.
I looked and there are a pair of half nuts (as distinct from split nuts) at the top. I'd never noticed them before. Thanks for making the suggestion. That's a useful discovery.
No, there's no space for a nut within the pointer. It is just crimped onto a reduced diameter section of the rod at the top.
No, it's definitely a one-piece head casting. There isn't even a wing bolt for locking the quill. It's a very cheap drill press, but to be fair it performs adequately for many jobs. It is not useless.
Hopefully I've explained the features of the drill press, but if you'd like a picture I'm more than happy to post one.
Now I've discovered the system for limiting the travel of the quill, I'll use it. It's going to be superior to either tape or drill stops.
I do expect a set of thin screwdrivers to see a considerable amount of use.
This is why I was thinking of starting with a good quality screwdriver. I would hate to grind one to exactly the right size, then find it only lasted a short time.
Allen keys are a useful source, and one I hadn't thought of. Thanks for that idea. But a box of 100 is about the same price as that thin bit set from Brownells. Due to the unknown amount of time and experimentation it will take me to make a good screwdriver bit, I am drawn towards the Brownells set.
I have a thing against electric screwdrivers. While they may be faster and have an adjustable torque limit on some models, I find they give poor control with slotted screws. I just prefer to use a normal screwdriver and estimate the required torque. I have only once damaged a thread in this way, and that was a long time ago, so I don't think I'm doing too badly.
I think that some, though not all, screws with narrow slots have larger heads than standard screws today. The traditional large "cheese" head is becoming very uncommon.
It is also possible that in some cases narrow slots were intended to signify that a high torque was not required (there are, of course, other reasons for using a large diameter screw). But this is just my speculation.
Indeed. Not something I generally do to them, though. It probably also makes the handle plastic less likely to fail under torque at the junction with the metal. But the Wera plastic is much less brittle than that used on cheap screwdrivers, so there's an advantage to start with.
Having discovered that parallel ground screwdrivers are available, I am a little surprised to find that the Wera screwdrivers are taper ground. Next time I might look for parallel ground screwdrivers, although doing a quick search I could only find one set by Pachmayr, and that was in the US. The other results were for screwdriver bits.
Having said that, I rarely have problems with my taper ground screwdrivers when the correct size is used in an undamaged slot with adequate axial force.
Or, in some cases, just stamped with the letters even though the steel is nothing of the sort. Someone sued Rolson Tools in the UK over this, and the company got fined a large sum of money.
Gunner, I checked out the Chapman sets in detail. The 8900 set looked the most suitable, so I studied the sizes in detail. It looked a good buy and I almost bought it.
But I'm really glad I had the foresight to get my feeler gauge set out and measure a few screw heads in the electrical equipment and clocks I intend to work on. Some slots turned out to be 20/1000", perhaps half of the total. The rest were 25/1000". The feeler gauges fitted the slots really closely, so I'm pretty sure they're intended to be these sizes. The gauge fitted better than a taper ground screwdriver bit. You could be absolutely sure when you had the right size. I guess this is one of the disadvantages of a taper ground bit.
So I need a set with bits which are 20/1000" thick. The Brownells set is increasingly looking like the best option. But I'm going to have to steal myself to make the purchase, as the delivery and likely import tax will be high.
I notice that Brownells offer two handles. A magnetic handle and a "clip-tip" handle. Initially I was inclined to go for the magnetic handle so that I could use it to hold steel screws. But now I'm not sure as I think the "clip-tip" handle may hold the bit more tightly. Some magnetic handles do not hold the bit tightly enough. Anyone have an opinion on which handle is better?
Understood -- though a thin slot screw should not be using much torque anyway.
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With the possibility of making several hundred (at least 200) from the hex keys. Compare that to the number of bits in the Brownells set.
O.K. You still should *try* making a screwdriver of your own, to see just how difficult is is (or isn't).
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Put a sleeve over the head -- just large enough to cover the diameter of the screw head. You can even get straight bits with a spring-loaded collar for the purpose. The screwdriver which I made for English system concertina endbox screws includes such a sleeve to keep me from slipping and gouging the wood of the endbox. And I never use an electric screwdriver with those, as the threads are fast enough and the thread engagement is slow enough to be no problem.
As it turns out, I don't often use slotted screws. When I am building something from scratch, I tend to choose Allen head cap screws and button head screws with Allen sockets for most things, with security Torx used for a few things. And I often work on things fitted with a lot of Phillips screws, but seldom slotted ones these days. And for wood screws, I prefer the Robertson (square drive) screws.
I just used it this evening for swapping subassemblies between two Exabyte Mammoth (8900) computer tape drives. Almost everything in there uses screws of 2mm diameter (1.96mm from measuring a typical one) and the lowest torque setting (1) on this driver releases at the right point to avoid overdriving these into the relatively soft metal of the chassis. The more serious problem was finding the right size (T6) of Torx bit -- but they can be found in 1/4" hex shank size.
There are two intermediate clicks between (1) and (2) on the electric screwdriver (and it goes up to (6)). I use the (2) setting commonly on both the 6-32 screws and the fairly common 3mm ones used for mounting tape and CD drives in computers.
I also have a set of two manual torque limiting screwdrivers by Utica. 6-30 Lb-In, and 0-100 Oz-In. Both of these also accept 1/4" hex shank bits (as well as adaptors to a 1/4" square drive for sockets.) The most frequent use for these (aside from the spare of one which I keep with my best English system concertina) is in removing and replacing CPU modules in Sun Blade 1000/2000 systems and Sun Fire 280R (same system board and CPU modules). Sun considers the torque important enough here so they supply torque measuring screwdrivers with the systems -- the one with the Sun Blade 2000 and the Sun Fire 280R is better than the rather simple design in the Sun Blade 1000. (According to the manuals, later systems were shipped without *any* torque driver, but the torque drivers were supplied when you bought replacement or upgrade CPUs. They also clearly spell out the needed torque (5 Lb-In) for those who have a general purpose torque screwdriver such as mine. The jackscrews take a Robertson (square) bit, and are marked with a fluorescent green ring around the screw holes -- matching the color of the torque screwdriver body, or the plastic carrier holding the earlier design (a ring which closes at the proper torque) which slides between the two disk drives in the system.
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Yes. Possible.
When were these made? And where? IIRC they are in clocks, but from back in the period when most hardware was custom made by the clockmaker, or from when production lines and supplies were more common?
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I did qualify that treatment as abuse, after all.
I've never had even a cheap screwdriver handle break on me. Granted, I don't pound on the ends with a hammer. :-)
Indeed so.
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There have been similar problems with drill bits from China -- marked as M2 HSS -- but being nothing of the sort. Some have caught partway through the drilling and been turned into reverse spiral bits. :-)
What this really means is that the slots were cut by milling cutters of those thicknesses. I've set up to make screws for English system concertinas (I've settled on M3.5x0.45 since the original thread matches no current standard), and among other operations, I made a block which will hold 20 screws in four rows. I have four slotting cutters on the horizontal mill's arbor so I can slot all of them in a single pass. IIRC, the cutter thickness for these is 0.0156" (1/64th") -- selected to match the slots of older concertina endbox screws. Once you are set up with a single slitting saw size, you really don't want to change frequently, so they used what they had for all the screws, instead of making each to a dimension appropriate to the job.
Many modern screws are made by "heading" the stock which carried the thread -- bashing it into a die which causes it to take on the appropriate shape -- and often also drives the slot into it at the same time, instead of cutting it. Given that, such modern screws are likely to have slots which are a better fit to a taper-ground screwdriver than to a parallel ground one. :-)
It depends on how the screws were made. Clock screws will have the slot cut by slitting saws in a milling machine (or a clockmaker's lathe acting as a milling machine).
You mean that you will have to illegally take other's property? Or did you really mean "steel yourself"? :-)
I would avoid the magnetic style when working with clocks and tape recorders, as both can be damaged by magnetic fields. In a clock (or a watch) the magnetic field can cause alternate layers of the spiral spring on the balance wheel to stick together. (Not a problem with pendulum clocks, of course), and with tape recorders, the magnetic field can magnetize the tape heads resulting in a serious increase in hiss.
But the selection really is normally a function of the bits being purchased. The ones to be held magnetically are very short bits, while those intended to be held by the "clip-tip" are longer, and have a groove turned near the end into which a ball detent drops to keep the tip from falling out. I tend to use the latter design most of the time, but you can get magnetic holders which will fit into the "clip-tip" style body when you need to handle less common bits. For example, I have a set of bits which contains 100 pieces, of which all but 4 are different sizes of bits. There are duplicates of the most frequently used sizes and style -- 5 copies of then #2 Phllips, while only one each of #0, #1 and #3. Same for the Pozidrive bits (Phillips with a extra set of points in the inner folds of the socket).
1 each of the four Robertson (square drive) bits #0 through #3.
9 slotted bits -- in metric widths. The 3mm width is 0.020" thick. The 4mm and 4.5mm are 0.032" thick. going up to 0.058" for the
8mm one.
Then four slotted bits with split points.
9 Torx bits from T8 to T45 (The smallest is not small enough for the Exabyte drives -- but I have those from other sources).
9 Security Tork bits covering the same range, but with a hole in the end to clear a pin in the screw's socket.
#6, 8, and 10 offset Phillips (the wings are not true radii.
#1, 2, 3, and 4 tri-wing -- like the offset Phillips, but only three blades.
Metric Allen from 1.5mm to 8mm
Imperial Allen from 1/16" to 1/4"
Three "clutch tip" bits, #1, 2, and 3
Three spline bits -- M5, M6, and M8
Metric Security Allen from 2mm to 6mm
Imperial Security Allen from 5/64 to 5/32 (in 64th).
In addition to these, there is a clip-tip to magnetic holder, A Y driver -- intended to drive cup hooks and small eyes. a 1" long and a 2" long adaptor from 1/4" hex to 1/4" square drive.
And -- a coupler going the other way from 1/4" square to 1/4" hex.
All in all -- a rather useful set to cover the strange ones which I don't have otherwise. I already had the tri-wing and the offset Phillips (as well as normal Torx, Allen and the security versions of both. But the Clutch (once common in automobile assembly in the USA), the spline bits, and the Metric Allen bits.
What there is *not* in the set is any form of handle. You are presumed to have the handle, or the electric screwdriver, or both already. (Actually -- I even have an adaptor from my Gerber folding pliers to the hex.)
All in all -- the hex bits are a good thing to have, since you can find weird ones in hex bits more easily than with a full shank and handle. And you can certainly carry a lot more styles in a collection of hex bits with a single handle than a full set of screwdrivers with handles.
The Security Allen used to be used on PC power supplies by some makers -- to keep users out of the power supply. :-)
From the point of view of consistency, I feel a bit bad describing a screwdriver tip as 3/8" x 0.025". I was using fractions for the larger dimension earlier, so I decided to be consistent. Using fractions and decimals together seems weird.
Strange size. I thought the standard M3.5 pitches were 0.35 mm (fine) and 0.6 mm (coarse).
Good point. I imagine that if the slot is formed in a die, it will end up being slightly tapered.
You're right. I did mean "steel myself". Thanks for correcting me!
I hadn't thought of this. Thanks for pointing it out. I'll probably go with the "clip-tip" style of handle now.
It seems that the Brownells bits will fit either type of handle.
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