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Alexam

Bandsaw Boxmaker
Joined
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Wythall, near Birmingham
Having problems at just recently with my power screwdrive not driving the screw all the waty before the chuck gives up. Not sure if it's the screwdriver bit (which I suspect) or the power unit not offering enough power before slipping the clutch. I have tried different positions and bits, but probably have older bits that don't match the screw head. Any ideas?
Malcolm
 
New bits? Screwdriver bits should be considered a consumable and replaced once they get rounded an uncooperative. They can be freshened up with careful filework, but it's rarely worth effort compared to fresh bits.
 
If the chuck slips but the bit doesnt, then the wood is harder than you think and just increase the slippage number.

If everything just slows and stops then its the battery.

if the bit spins round on the screw head then either the bit is too worn or you have the wrong one. (assuming you are screwing in square to the screw and not at an angle.
Check on the screw box for the type of head and get bits accordingly.
 
Assuming these are cross-headed screws...

1. Check which you have, Phillips or Pozi-headed screws.
In our field of interest, we only encounter Phillips in some flat-pack furniture and plasterboard ('drywall') screws. They are designed to cam out once the screw is set, which is why they are common in manufactured goods. They are also intended to be 'use once, discard afterwards' because the camming-out inevitably damages the head.

It's a bit hard to describe, but Phillips have a more sharply defined cross shape, and the drivers are more pointy and marginally thinner than Pozi. IMHO, they are nasty things, best put straight into the metal recycling box without any attempt to actually use them, but then I used to see them a lot in electronic equipment.

Pozi, are more easily identified, because there are extra mini-splines at 45 deg. to the main cross. This is clear on the drivers, and there are usually thin lines (at 45) stamped on the head of the screw too.

2. If they are Pozidriv screws, do they have single- or double- start threads?
Double-start means two intertwined threads along the screw, rather than just one spiral. They are good for speed on-site, but they require more torque, and (as I have found out the hard way) they are unsuitable for certain tasks such as door hinges and holding down plywood floor coverings because they can unscrew themselves when subjected to "wiggling" forces (moving a door or footfalls on flooring). They work best in longer lengths for a given size - short ones are just silly, and shouldn't really be made in the first place, to avoid mistakes in use (DAMHIKT). The double-start threads work best in softwood, intended for framing or other site applications.

The ones with a self-cutting tip/thread (either/or obvious serrations or a cutting edge ground along the conical tip of the screw) usually have an even weaker grip still - they drive nicely, but at the cost of cutting a bigger hole with less thread engaged per inch. Sometimes the makers compensate by exaggerating the thread compared to the shanks. These do grip, but the chances of chewing up the screwhead in use or snapping it off are usually much greater.

3. What state are the screwdriving bit(s) in?
Wear swiftly makes them useless. I have given up using ordinary bits now, hardened or otherwise. I only use decent-quality diamond-coated bits (usually Wera, because they are easy to find). They last far longer, and most importantly don't cam out of the screw head normally, as the diamond digs into the screw, locking the two together whilst torque is applied. If you don't use them, I recommend trying some - you won't go back to the ordinary ones! I have only one Phillips bit, also diamond, but identified with marker pen, so it doesn't get muddled with the rest.

4. Is the slipping clutch of the drill in good condition?
You say, "...the chuck gives up." I'm not quite sure what you mean, but the clutch on my Bosch 10.8V drill driver is noticeably worn now after 5+ years of DIY use. I don't think there is any practical fix - it's just slowly wearing out (my SDS drill is giving up too, probably also wear).

5. Finally, do you find you need to charge the battery more often?
As they age, their ability to deliver torque as well as duration falls off. It might be time...
. . .
Personally, I'd first try diamond bits, and adopt the rule that you throw any screw that has been inserted more than twice into hardwood, or that has ever had the driver slip whilst being driven. Life is too short to be rescuing damaged screws.
Also only use single-start screws for all but rough work into softwood, and wax them with a tea-light or similar before driving. Always a pilot hole in everything, except softwood framing/floorboards/decking, too!

If the above doesn't help, probably either a new battery or drill, I'm afraid.

HTH E.
 
Thanks all.
Eric, I think its probably the bits. I have had them for years and its on;y recently that I seem to be getting problems. A little shopping is called for I belive. Thanks again
Malcolm
 
if it is the bits, it is worth paying a bit more for a wera (or other brand) rather than the cheapest toolstation ones.
 
Just back with anew set from B&Q to see if it makes a difference. Wish they would just standardise screw heads as it would make life o much easier.
 
It's not too bad - most people will use a PZ2 90% of the time, and maybe a PZ1 or PZ3 the rest of unless they're plasterboarding or dismantling commercially assembled stuff. A PZ2 fits from 3.5mm to 5mm, many of us don't use larger or smaller.
 
Alexam":374g8prf said:
Just back with anew set from B&Q to see if it makes a difference. Wish they would just standardise screw heads as it would make life o much easier.
The nice thing about standards is that there are so many to choose from!

BugBear
 
Robbo3":19498w1v said:
A right angle ratchet screwdriver is good for added torque plus it gets in tight spaces eg
- http://www.ebay.co.uk/itm/11-Piece-Righ ... SwUKxYgirz

Someone gave me an angled ratchet screwdriver. I'd never used is, regarding it as a gimmick, until... I was trying to construct something in a conservatory in July. The heat meant my hand was constantly clammy, and I just couldn't get any purchase on the screwdriver. Gimmick tool saved the day.
 
Eric The Viking":o8kd7olk said:
Assuming these are cross-headed screws...

1. Check which you have, Phillips or Pozi-headed screws.
In our field of interest, we only encounter Phillips in some flat-pack furniture and plasterboard ('drywall') screws. They are designed to cam out once the screw is set, which is why they are common in manufactured goods. They are also intended to be 'use once, discard afterwards' because the camming-out inevitably damages the head.

What does cam out mean?
 
The screwdriver bit comes out of the slots and in doing so damages the slot

You can (if you are cack handed like me) do this with ordinary slot screws. Phillips/ pozi was supposed to reduce the chance but I guess most of us have become even more complacent as a result.
 
Another issue is that not all screw heads are as well formed as others. Most philips/pozi screws that come packed in with fittings have very shallow formed slots for the driver so the bit doesn't fit in properly, Goldscrews from ScrewFix also seem less able to grab the bit than Spax or Reiser, possibly why the latter cost so much more.

A decent new bit with a decent new screw will lock together very snugly and you can almost wave the two about together, everything else just falls off.

If you do a lot of fastening, bits are very expendable, I've often got through several in a day. I'm not convinced by the super duper Wera bits either as I got through one of them in a day (admittedly not diamond, but for impact driving) and it didn't seem any longer lasting than the DeWalt bits mentioned so wasn't worth the 5 times it cost. I've also found the diamond ones to not last much if any longer than other branded bits. However that's driving hundreds of screws in far from ideal circumstances.
 
Eric The Viking":75gxe9aa said:
In our field of interest, we only encounter Phillips in some flat-pack furniture and plasterboard ('drywall') screws. They are designed to cam out once the screw is set, which is why they are common in manufactured goods.
Thought you might like to know that's a myth. It supposedly stems from a mis-read of the original patent but it clearly states they were not designed to do this, in fact the exact opposite!

Phillips screwdrivers in the real world are of course very prone to it, as most people will have seen firsthand at some point, but the ease with which they cam out is apparently due to variation from the original specs in both the screw recesses and the driver.
 
I go through a lot of screwdriver bits, the dewalts are ok, dewalts impact (black box) are complete garbage, addax v5 are decent, wera are the best I've tried.
 

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