[Tim Watts[_2_]]

Could someone please confirm if I've right he

A 2mm[1] wide slot would accomodate an M2.5 threaded bar;
A 4mm[2] wide slot would accomodate an M5 threaded bar?

[1] A 2mm HSS drill shank sit shappily in the slot - a 2.5mm dill will
not.

[2] A 4mm drill shank sits in the slot.



----

Why?

It's that screed floor that has a crack down the middle (builder cock
up[3]). I have decided to angle grind 30cm long slots perpendicular to
the crack acorss the crack at 30cm intervals.

I will then resin A2 stainless threaded bar into these slots using Uzin
KR416[4]:

http://www.pwflooring.co.uk/subfloor...in-kr-416.html



My wall chaser cuts slots with 2mm drill shank clearance, and I can
acheive a 4mm slot if I clamp the two diamond discs onto each other[5].

So I'm deciding what size bar to buy...


Cheers,

Tim

[3] Don't get me started on builders. Every bloody time I have to fix
something... And I trust me more, so no, not calling them back... Too
much hassle.

[4] It's a low viscosity resin designed for the job with screed
penetrating characteristics.

[5] Seems dodgey but a test run indicates the chaser is not unhappy. I'm
well protected by shielding so the risk is low.


--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal
coverage

[Bob Minchin[_4_]]

Tim Watts wrote:
Could someone please confirm if I've right he

A 2mm[1] wide slot would accomodate an M2.5 threaded bar;
A 4mm[2] wide slot would accomodate an M5 threaded bar?

[1] A 2mm HSS drill shank sit shappily in the slot - a 2.5mm dill will
not.

[2] A 4mm drill shank sits in the slot.



----

Why?

It's that screed floor that has a crack down the middle (builder cock
up[3]). I have decided to angle grind 30cm long slots perpendicular to
the crack acorss the crack at 30cm intervals.

I will then resin A2 stainless threaded bar into these slots using Uzin
KR416[4]:

http://www.pwflooring.co.uk/subfloor...in-kr-416.html



My wall chaser cuts slots with 2mm drill shank clearance, and I can
acheive a 4mm slot if I clamp the two diamond discs onto each other[5].

So I'm deciding what size bar to buy...


Cheers,

Tim

[3] Don't get me started on builders. Every bloody time I have to fix
something... And I trust me more, so no, not calling them back... Too
much hassle.

[4] It's a low viscosity resin designed for the job with screed
penetrating characteristics.

[5] Seems dodgey but a test run indicates the chaser is not unhappy. I'm
well protected by shielding so the risk is low.


Neither statement is correct
2mm slot needs M2 thread to fit in it
4mm slot needs M4 thread to fit in it

The core diameter of M2 thread will be 1.6mm - bu88er all strength
Core of M4 is 3.3mm and so 4 x the cross sectional area of the M2

[Tim Watts[_2_]]

On Sunday 19 January 2014 19:49 Bob Minchin wrote in uk.d-i-y:

The core diameter of M2 thread will be 1.6mm - bu88er all strength
Core of M4 is 3.3mm and so 4 x the cross sectional area of the M2

I agree that M2 is getting rather too weedy - as I replied to John, I
shall chance doubling up my wall chaser discs to cut an M4 capable slot.

I never got the hang of screw dimensions (any any format!).

--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal
coverage

[Tim Watts[_2_]]

On Sunday 19 January 2014 19:49 Bob Minchin wrote in uk.d-i-y:

Neither statement is correct
2mm slot needs M2 thread to fit in it
4mm slot needs M4 thread to fit in it

The core diameter of M2 thread will be 1.6mm - bu88er all strength
Core of M4 is 3.3mm and so 4 x the cross sectional area of the M2

Thanks John.

In that case I must have misunderstood this:

http://www.tribology-abc.com/calculators/metric-iso.htm

- it said M2.5 needs a drill diameter of 2.05mm. Is that because a
2.05mm shank drill actually drills a 2.5mm hole?

In that case, i shall have to double up my discs and use M4.

M2 threaded bar is not readily available and is probable too thin.

--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal
coverage

[Nightjar]

On 19/01/2014 20:12, Tim Watts wrote:
On Sunday 19 January 2014 19:49 Bob Minchin wrote in uk.d-i-y:

Neither statement is correct
2mm slot needs M2 thread to fit in it
4mm slot needs M4 thread to fit in it

The core diameter of M2 thread will be 1.6mm - bu88er all strength
Core of M4 is 3.3mm and so 4 x the cross sectional area of the M2

Thanks John.

In that case I must have misunderstood this:

http://www.tribology-abc.com/calculators/metric-iso.htm

- it said M2.5 needs a drill diameter of 2.05mm. Is that because a
2.05mm shank drill actually drills a 2.5mm hole?...

Those are tapping drill sizes - the hole you drill when you want to cut
that thread in some material. A clearance drill is needed to give a hole
that the thread will enter freely. This gives both tapping and clearance
drill sizes:

http://www.engineeringtoolbox.com/me...ads-d_777.html

Colin Bignell

[Tim Watts[_2_]]

On Sunday 19 January 2014 20:18 Nightjar wrote in uk.d-i-y:

Those are tapping drill sizes - the hole you drill when you want to
cut that thread in some material. A clearance drill is needed to give
a hole that the thread will enter freely. This gives both tapping and
clearance drill sizes:

http://www.engineeringtoolbox.com/me...ads-d_777.html


Thank you sir! That is a much better table than the one I found... And I
get the point about tapping vs clearance - but it was not clear form my
initial googling....

http://www.metals4u.co.uk/ seem to have the best prices for metre
lengths of A2 threaded bar.

Here's what I'll cutting and dropping the bar into:

http://www.flickr.com/photos/timjwatts/12037285193/
http://www.flickr.com/photos/timjwatts/12037025135/

BTW - the bright light in the background is one of these:

http://www.toolstation.com/shop/L/s/.../sd2480/p45540

I'm very impressed - LED and rechargeable. I really got it for the
wiring work in the roof space - cold running and shock proof were the
main things.

--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal
coverage

[John Rumm]

On 19/01/2014 20:12, Tim Watts wrote:
On Sunday 19 January 2014 19:49 Bob Minchin wrote in uk.d-i-y:

Neither statement is correct
2mm slot needs M2 thread to fit in it
4mm slot needs M4 thread to fit in it

The core diameter of M2 thread will be 1.6mm - bu88er all strength
Core of M4 is 3.3mm and so 4 x the cross sectional area of the M2

Thanks John.

In that case I must have misunderstood this:

http://www.tribology-abc.com/calculators/metric-iso.htm

- it said M2.5 needs a drill diameter of 2.05mm. Is that because a
2.05mm shank drill actually drills a 2.5mm hole?

No, that's the size of drill you need if you want a hole ready for
tapping to M2.5

The 2.05 is the minor diameter of the thread (i.e. if you measure the
internal diameter of a M2.5 nut, that is what you will measure), but the
major diameter (i.e. the diameter of the bolt) is 2.5mm


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

[Tim Watts[_2_]]

On Sunday 19 January 2014 20:27 John Rumm wrote in uk.d-i-y:


No, that's the size of drill you need if you want a hole ready for
tapping to M2.5

The 2.05 is the minor diameter of the thread (i.e. if you measure the
internal diameter of a M2.5 nut, that is what you will measure), but
the major diameter (i.e. the diameter of the bolt) is 2.5mm



OK - all clear now - Ta muchly! Glad I asked - PITA mistake that
would have been!

--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal
coverage

[charles]

In article ,
Tim Watts wrote:
On Sunday 19 January 2014 19:49 Bob Minchin wrote in uk.d-i-y:

Neither statement is correct
2mm slot needs M2 thread to fit in it
4mm slot needs M4 thread to fit in it

The core diameter of M2 thread will be 1.6mm - bu88er all strength
Core of M4 is 3.3mm and so 4 x the cross sectional area of the M2

Thanks John.

In that case I must have misunderstood this:

http://www.tribology-abc.com/calculators/metric-iso.htm

- it said M2.5 needs a drill diameter of 2.05mm. Is that because a
2.05mm shank drill actually drills a 2.5mm hole?

I'd assume that was the start hole for tapping a thread. Clearince would
be the same size as the bolt plus a little more for comfort.



In that case, i shall have to double up my discs and use M4.

M2 threaded bar is not readily available and is probable too thin.

--
From KT24

Using a RISC OS computer running v5.18

[John Rumm]

On 19/01/2014 18:41, Tim Watts wrote:
Could someone please confirm if I've right he

A 2mm[1] wide slot would accomodate an M2.5 threaded bar;
A 4mm[2] wide slot would accomodate an M5 threaded bar?

Seems unlikely, unless I have missed something. The outer diameter of
the metric thread is the size specified. So M5 bar will have a 5mm outer
diameter (the minor diameter will be near enough 4mm - but that is not
going to help getting it into a slot!)



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/