posidrive screw & bit combination burring out

[Ouch77]

I've got a project where I'm needing to drive some 6x150mm woodscrews into timber joists (a pair of 4x2" for simplicity sake).

The screws I got are goldscrew PZ double countersunk, which are by and large fine. The problem I'm having is the PZ3 driver bit is struggling at maximum torque to stay engaged. I'm pre-drilling as deep as I can to give myself an easy life, but the final 10mm of travel is a battle. I'm using a tired dewalt driver, but even with a significant amount of force (upper body weight) bearing directly down I'm still occasionally camming out of the head. I appreciate I'm probably at the limit of what can be expected of a Posidriv head, and with hindsight I would stump up the extra cash and use torx or countersunk hex drive, but here I am.

I'm using new DeWalt driver bits, bought for the job, but I can't help thinking the point, even on the PZ3 is a little long on the tip meaning I'm not getting full contact on the flanks. I'm considering filing the end off a spare bit and trying that for a few of the stubborn screws that just don't want to go in all the way.

Has anyone else tried this approach? any successes you'd like to share? Is there a manufacturer who has a track record for good driver bits?

 

[rsgaz]

the point, even on the PZ3 is a little long on the tip

That doesn't sound right at all. A PZ3 should look kind of blunt. Can you photograph a close up of a bit for us?
A good bit should fit so well that you can hold the screw and pick up the drill horizontally!

A longer pilot would be a good start if you cannot reach full depth with what you have. 4.2 or 4.5 probably for those screws.
https://www.ebay.co.uk/itm/162036000228

 

[Ouch77]

drilling at 5mm pilot, but my drill bit is only long enough to get 2/3 the way through the top timber. Will supply photos when I get home, I don't bring my tools to work as I work in an office

 

[SFK]

Ouch,
PZ#3 works fine for me - and I confirm it is what it says is recomended on the box of screws.

I frequently use the 6x120mm goldscrew(when on budget and speed does not matter) and goldscrew-plus (when not on budget and speed does matter).
The long goldscrew often stick and eject the bit for me too, a bit less often also happens with the long goldscrew-plus.
https://www.screwfix.com/p/goldscre...k-multipurpose-screws-6-x-150mm-50-pack/2873f
So I now (when I remember) use a 4mm drill to make a pilot hole about half to 3/4 the length.

EDIT: I saw that you say that you are already doing a about 100mm long pilot hole. That is strange as that is also what I do. Could have a look for a longer 5mm drill, but as most are 85mm long I would perhaps bodge it with a 132mm long HSS: https://www.screwfix.com/p/erbauer-straight-shank-hss-drill-bit-5-x-132mm/7607v

SFK

 

[JohnD]

maybe the bit has gone pointy with age and wear.

for m6 x 150mm I prefer hex-headed coachscrews, but they might not suit your job. They take immense torque.

 

[Ouch77]

EDIT: I saw that you say that you are already doing a about 100mm long pilot hole. That is strange as that is also what I do. Could have a look for a longer 5mm drill, but as most are 85mm long I would perhaps bodge it with a 132mm long HSS: https://www.screwfix.com/p/erbauer-straight-shank-hss-drill-bit-5-x-132mm/7607v

SFK

Nah, pilot hole is about 75mm deep tops - I'm using regular length HSS drills. My primary concern was to stop splitting a I'm going across the longer section of the timber, for this the hole has been successful, and I typically only hit real real resistance when I get the screw into the older, second timber.

 

[Ouch77]

maybe the bit has gone pointy with age and wear.

for m6 x 150mm I prefer hex-headed coachscrews, but they might not suit your job. They take immense torque.

Screws need to be countersunk, and with hindsight I'd have used torx or hex drive, but here I am. The driver bit has shown a bit of wear, but this is on the driving edges, I've got a second, fresh, bit and will pick up a few more when I next pass the tool-factors.

 

[cdbe]

I take it you're using an impact driver and not a drill/driver?

 

[Deleted member 174758]

Well, you already have the solution for extra long screws - go to Torx drive screws and matching bits if possible for zero cam-out.... But in the meantime, yes PZD#3 bits should have flat end, and yes, I've sometimes resorted to grinding the ends off a wee bit to get a better fit, but TBH diamond coated PZD#3 bits, such as Wera Impaktor do work a bit better than plain bits. See Toolstation for details.

 

[Ouch77]

I take it you're using an impact driver and not a drill/driver?

Nope, I'm using my somewhat decrepit dewalt DC740 drill-driver. With a full battery it's still got enough torque (appartently 20Nm, but I'm not sold) to cam out with me leaning my upper body weight right down through it.

 

[SFK]

Ouch
As you have the screws and do not want to get new ones, for your 6x150mm screws I would get one of these 300mm long wood drill bits and drill a 4mm x 130mm pilot (20mm short for the tapered end of your screws) .
https://www.ebay.co.uk/sch/i.html?ul_noapp=true&_nkw=long+wood+drill+bit+4mm&rt=nc&LH_PrefLoc=1
or
https://www.amazon.co.uk/dp/B075F3J...t=&hvlocphy=1006457&hvtargid=pla-599573122757
SFK

 

[Ouch77]

Ouch
As you have the screws and do not want to get new ones, for your 6x150mm screws I would get one of these 300mm long wood drill bits and drill a 4mm x 130mm pilot (20mm short for the tapered end of your screws) .
https://www.ebay.co.uk/sch/i.html?_nkw=long+wood+drill+bit+4mm&ul_noapp=true
SFK

Nice - I think I prefer that approach, irritating in some ways as I bought a single long drill of a larger size a little while back for what I'd considered a one-off job. Seems now I should have got a set :-/

 

[SFK]

Even though I suggested them, at those prices and from ebay I would not expect that set to last too long :>

 

[cdbe]

Get an impact driver for Christmas. I've recently got one of these:

Looks like a toy but bangs in 6" woodscrews for fun.

 

[scbk]

Ideal job for an impact driver.

In the meantime, rub a bit of soap on the threads of the screws before you put them in