How do i get the perfect drill hole width?

[robinbanks]

Take the screw you plan to wind in and hold it next to the drill bit so the tip of the screw and the tip of the drill bit are next to each other, then move the screw at least 5 mm towards the drill (away from the point of the drill bit). Wrap electrical tape around the drill bit next to where the head is

Now drill your wall until the electrical tape is just about to touch the wall surface. You have now drilled a hole 5mm deeper than the screw is long, so you won't encounter any issues with the screw bottoming out/not winding all the way flush

Be mindful of the wall construction too; if there is a thick layer of soft plaster (assess it as you drill) on the wall before you get to the harder brick/stone then you'll need to drill all the way through that, so you'll need to add on the thickness of the plaster when tape marking the bit. To get the plug past the soft plaster part you can use the screw itself, plus a hammer to tap the plug down into the hole. Remember that you'll need longer screws, and also maybe thicker screws if they will have something heavy on them, bending them (the plaster part of the wall won't offer much support) ; the fixings you choose will depend on how the item you're fixing is used, what loads it experiences in service, and whether those loads strive to slide down the wall, pull away from the wall etc

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Nearly 100% of the time that you buy something, it will come with the crappiest screws and plugs you will ever find. Bin them without even trying to use them, and keep a stock of decent plugs and screws

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Make sure you're using the right screwdriver bit for the screws you have. Just because they're a + shape doesn't not mean they're designed to go together. If you have PH screws, use PH a bit of the right size. If you have PZ screws, use a PZ bit of the right size. Generally the screws you will use for mounting things will be PZ, and the + shape in the end of them will have an x shape overlaid on it. PZ bits look more aggressive than PH bits, with extra sharp vanes between the + shape that drives the screw

In the pic above the correct bit for the correct screw are touching each other. Don't mix the types, unless you're really competent. Newbies that mix the wrong bit and screw typically end up destroying the bit, the screw or stabbing themselves in the finger with the driver

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To clear the hole, insert a straw and blow down it, but shut your eyes before you blow

 

[Harry Bloomfield]

The last few mm of the plug stick out. If i try hammering the plugs in, they just warp and deform, going nowhere, because they are plastic i guess.

Usually because the hole is just not deep enough. You need to drill the hole, deep enough, that the entire plug goes through the plaster, into the brick, then allow some extra for the dust to compact, in the hole, beyond the plug.

 

[Diver Fred]

You should never let the inserted plug finish flush with the surface if plastered - it should always be inserted deeper, usually by using a screw or punch (the tip of which is the same size as the plug head) to finish at the brick face. Drill the hole 5 to 10mm deeper than the plug is long. It doesn't matter if the screw passes past the end of the plug.

 

[footprints]

Bit of vaseline on the screw or scrape across a wet bar of soap, we used to use tallow in the old days.

 

[Nanako]

You should be drilling 6-10mm longer than screw or it will bind.

no worries about this, i don't even bother measuring when i'm going into a wall, i just go the entire length of the drill bit, which in this case is about 150% of the length of the plug, plenty of space
enough, in fact, that one of my plugs has slipped farther inside a bit, i dont see any problem with this, that just means more of it is in masonry instead of plaster, and it holds firm

 

[Nanako]

You should never let the inserted plug finish flush with the surface if plastered - it should always be inserted deeper, usually by using a screw or punch (the tip of which is the same size as the plug head) to finish at the brick face. Drill the hole 5 to 10mm deeper than the plug is long. It doesn't matter if the screw passes past the end of the plug.

but then why do plugs come with a little lip designed to prevent exactly this? Even the fischer ones

 

[endecotp]

with considerable effort for the last 10mm or so

It sounds like you have actually reached the brick, rather than just the plaster.

For anything substantial, including these handles you are fitting, you do need to fix into the brick. The plaster is much weaker. Get screws that are long enough, and drill holes that are deep enough. Push the plugs in so they are at least mostly in the brick.

 

[Scally-Ho]

Just use dry wood, never had a problem , I find they work better than many plugs.

Can you imagine employing a journeyman, who, incapable of thinking on his feet, returns back to base because he had run out of proprietary wall plugs? Here's your cards mate, now stop wasting my time

 

[Nanako]

Bit of vaseline on the screw or scrape across a wet bar of soap, we used to use tallow in the old days.

i'm pretty sure the screws were sticking because the plug couldn't expand anymore, but i guess lubricating them might be worth a try, i have a silicone lubricant spray i bought for door hinges, and some WD40, they'd probably do the trick right?

Are there any pitfalls or gotchas to worry about when lubricating screws? It seems like anything that makes them go in easier, would also make them come out easier?

 

[Nanako]

It sounds like you have actually reached the brick, rather than just the plaster.

For anything substantial, including these handles you are fitting, you do need to fix into the brick. The plaster is much weaker. Get screws that are long enough, and drill holes that are deep enough. Push the plugs in so they are at least mostly in the brick.

nah i always drill into brick now, i learned this lesson a while back, and thats why i don't use any screw+plug shorter than 60mm these days
its just that there wasnt enough space for the plug to expand, i needed to widedn the hole a tiny bit

 

[Scally-Ho]

@Nanako .. nowt worse that a dry screw

 

[Harry Bloomfield]

would also make them come out easier?

They would have to screw out, and they will not do that, without some help.

 

[Nanako]

@Nanako .. nowt worse that a dry screw

are you saying that you habitually lubricate your screws ? I have never done this in my life nor heard of it before today!

 

[Why Not Indeed]

Can you hear a whooshing sound? I believe he was employing humour.

 

[Nanako]

Well i have finally managed it, the grip bar now now securely mounted with four 8x65mm screws, it does not move under strain, i'm happy with this.

I did use lubrication on the screws, i'm not sure if it helped