How do i get the perfect drill hole width?

[Nanako]

i'm using 6 x 60mm plastic rawlplugs, and a 6mm masonry drill bit, so ive definitely got the right parts here as far as i can tell.
The bit i'm using is like these, with a slightly wider tip at the top that is exactly 6mm, and the main shaft of the bit is slightly narrower

i drill the hole all the way, i vacuum out the dust, and then i slide in the plug, and it only goes in most of the way. 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. No matter how i push with my thumb, they won't go in. My best guess is that despite being generally the right width, the hole is a bit ragged around the masonry deep inside, and tiny bits sticking out are blocking it

I want the thing i'm putting in to sit flush with the surface,

so i very carefully drill the same hole again to make sure its diameter is consistent all the way down, i have to do this about three times for each hole. Then the plug slides all the way in with only a little resistance, seems perfect!

I put all the screws in, and test my new grip bar. It pulls right out of the holes, gradually. Absolutely not safe. I can't seem to figure out how to get these holes just right, and get the plugs to go in properly

When evening out the hole, I'm as careful as i can be to make the drill straight in and out, and my hammer grip has a foregrip to help with stability, but i am only human, and i can't rule out the possibility that it is wiggling around a tiny bit and ends up making the hole wider than 6mm

Anyways these holes are worthless now, i need to redo this in a slightly different position. so i've put some filler in the holes And i figured it's best to ask for advice before i mess it up again.

1. How can i make holes that are just right for the plug, that will allow it to go all the way in, but also make it grip properly?

2. How far away from these failed existing holes will i need to drill my next set, in order to make sure that the previous holes don't affect the stability of the new ones? I had the perfect position for this grip bar and i don't want to move it very much from that spot

 

[aveatry]

I dont think you said what you are drilling into - brick? also what plugs are you using - some are useless. My favourite are fischer duopower wall plugs

 

[Scally-Ho]

IMO you are expecting too much from your masonry drills. When I find modern wall plugs a tad tight for my patience, I swiftly shave some wood along the grain to make my own slightly tapered plugs and after hammering them home I drill a narrow pilot hole before screwing my fixings home.

 

[Burnerman]

Fairly common this one!
No harm in using the drill to bring the dust out and it’s unlikely a vacuum cleaner would do this well.
Consider using a quality plug such as Fischer - they are tough and splined near the top.
Are you sure a 6mm plug is sufficient for this project?
John

 

[Nanako]

Fairly common this one!
No harm in using the drill to bring the dust out and it’s unlikely a vacuum cleaner would do this well.
Consider using a quality plug such as Fischer - they are tough and splined near the top.
Are you sure a 6mm plug is sufficient for this project?
John

i'm sure it's sufficient because i am actually re-fitting this grip bar. it was on my wall and solid for near 20 years, before a recent bathroom renovation. In the process of that, the old plugs and holes got plastered over, but i wanted to move it to a different angle anyways. The plugs and screws i'm using now are actually thicker and longer than what it was originally put in with

Different kinds of plugs are an interesting thought though, i looked up the fischer ones and they certainly seem like they would cope with hammering better

 

[Nanako]

IMO you are expecting too much from your masonry drills. When I find modern wall plugs a tad tight for my patience, I swiftly shave some wood along the grain to make my own slightly tapered plugs and after hammering them home I drill a narrow pilot hole before screwing my fixings home.

i'm having real trouble imagining what you mean here, making my own plugs out of wood sounds damn hard without a lathe, (which i dont have)

 

[Scally-Ho]

i'm having real trouble imagining what you mean here, making my own plugs out of wood sounds damn hard without a lathe, (which i dont have)

They don't have to be perfectly round, just roughly to shape and long enuf to sit proud to be cut off flush after hammering home. How do you think fixings were made before wall plugs were invented if wood was not used.

 

[Nanako]

They don't have to be perfectly round, just roughly to shape and long enuf to sit proud to be cut off flush after hammering home. How do you think fixings were made before wall plugs were invented if wood was not used.

i cant even make them remotely round, i just don't have the tools for this solution

Fairly common this one!
No harm in using the drill to bring the dust out and it’s unlikely a vacuum cleaner would do this well.
Consider using a quality plug such as Fischer - they are tough and splined near the top.
Are you sure a 6mm plug is sufficient for this project?
John

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What do you think of these? 8mm is obviously wider, but since it seems the holes are already wider than 6mm anyways, i may as well go up a size

 

[Burnerman]

Ah right......a grip bar to help in the shower or similar.......I was visualising some gymnastic item of horror for a while!
Keep at it with your 6mm masonry drill - a blast of air in the hole is good for clearing the dust out - and also giving you an eyeful.
In future if the plug sticks out a little, just snick the end off with a chisel - it happens all the time.
John

 

[Scally-Ho]

" cant even make them remotely round, i just don't have the tools for this solution"

@Nanako I bet you have a Stanley/craft knife. I use my knife to roughly cut plugs from scrap timber.
in a matter of seconds.

 

[Nanako]

Fairly common this one!
No harm in using the drill to bring the dust out and it’s unlikely a vacuum cleaner would do this well.
Consider using a quality plug such as Fischer - they are tough and splined near the top.
Are you sure a 6mm plug is sufficient for this project?
John

Help!
I'm almost there, a snag has appeared right before victory

I got the fischer plugs and screws i linked earlier, next day delivery, i got out my 8mm drill bit, and bored the same holes slightly larger, i put the plugs in

Like before, they went most of the way and stopped. However unlike before, i was able to tap them the rest of the way with a hammer, because these plugs are really sturdy, great call there burnerman

So then i'm trying to put the screws in, and running into a problem. The screws just won't go all the way. One of them went all the way in because the wall is softer there, possibly damp or a hole in the brickwork, but the other three refuse to go any farther. I'm using a screwdriver attachment on my drill, and leaning my whole bodyweight against it, and setting the speed down low, but either the drill doesn't turn, or it turns in place damaging the + part where it goes in, these screws are not moving

With the depth that they're at though, this grip bar is VERY sturdy, i dont think a team of wild horses could pull it off the wall now, its going nowhere

Should i try to take the screws and plugs out, and re-bore these holes a little more? I',m worried that might cause a repeat of the same issue that made me start this thread though

 

[Nanako]

disregard last post, ive decided to go ahead with the boring, very gradually, its taken an hour of careful re-drilling attempts and testing until i got each plug to a point where the screws can go all the way in, with considerable effort for the last 10mm or so but they go, this should be solid

 

[Harry Bloomfield]

@Nanako I bet you have a Stanley/craft knife. I use my knife to roughly cut plugs from scrap timber.
in a matter of seconds.

The problem with wood plugs, is that they eventually dry out, become loose, or in time rot. I only make wood plugs, in situations where the drilled hole, has to be at that spot, and it is to wide to work with a proper plug.

 

[foxhole]

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

 

[foxhole]

The problem with wood plugs, is that they eventually dry out, become loose, or in time rot. I only make wood plugs, in situations where the drilled hole, has to be at that spot, and it is to wide to work with a proper plug.

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