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drill/tap in frames



 
 
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  #11  
Old July 8th 18, 01:35 AM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 2,800
Default drill/tap in frames

On Sun, 08 Jul 2018 01:08:28 +0200, Emanuel Berg
wrote:

Jeff Liebermann wrote:

The tubing is probably too thin for threading
the hole. You need at least 3 full threads
wall thickness tubing to keep the mounting
screw from stripping the threads out of the
hole. For an M5x0.8, that's 0.8 mm per
thread. So, the minimum tubing wall thickness
would be 2.4mm. However, since the tubing on
your bicycle is probably around 0.5mm wall
thickness, the tubing wall will never be
thick enough to support threading. To get
more threads to grip is one reason why
builders use braze on bosses for
mount points.


I keep hearing this,


Then, it doesn't hurt to repeat it a few more times until you become a
believer. Please repeat a few hundred times:
"Thin wall tubing should not be threaded"

but it isn't the case for
my bikes which have chainguards.
These have three stays, and of those, two are
mounted on the bike frame with M5 screws.
Threaded hole, no nut on the other side!


How thick is the tubing at the 3 stays? Are you sure that there isn't
a Rivnut, PEM nut, or other threaded insert in the stays?

Then the chainguard is mounted on the stays,
likewise with M5s, threaded holes (only here
sometimes there are nuts as well).


How do you install a nut when the ends of the stays are all welded
shut? There's no sane way to install a nut inside the stays.
Hopefully, your machine does not have an M5 fastener going though both
sides of the stays, and secured by a Nyloc nut? Overtighten and
you'll crush the stays.

The stays are about 1mm. How thick the frame
tube wall is I don't know, but I can take
a discarded frame and cut it with an angle
grinder to find out, God willing.


The stays are likely to be double butted, with different thicknesses
at the ends, compared to the middle of the tube. If you don't mind
drilling a tiny hole in your scrap bicycle frame, you can easily
measure the thickness.
1. Drill a very small hole in one side of the tube. If you plan to
ride this bike again, drill on side of the tube that will drain water.
2. Make a straight pin that is long enough to go through the hole and
hit the opposite side while having a little stick out of the hole.
3. Measure the length of the pin accurately with calipers. Flatten
the ends if necessary.
4. Using the same caliper as above, measure between the projecting
pin end, and the far end of the tubing.
5. Subtract the length of the pin from the above measurement and you
have the wall thickness.
6. Plug the drill hole so water doesn't enter.

This ain't to say that rivnuts ain't a good
idea, of course.


Make sure you use steel Rivnuts on a steel frame. Never mind. It's a
dumb idea. An M5 Rivnut is going to require a 7.0 mm (+0.1/-0 mm)
hole. That's going to seriously weaken the stays. If you notch the
hole to prevent rotation of the Rivnut, you also get a stress riser.
Don't do it.

BTW, do you by them online? I don't think they
are in our HW stores... (which is common with
the stuff you guys mention: durometer, soft jaw
pliers, etc.)


Actually, I steal them from former employers and companies where I
consult. Same with other consumables, such as pop rivets, office
supplies, electronic parts, etc. I'm still using parts that I stole
perhaps 30 years ago.

I bought my durometer on eBay. I've never seen one in a retail
automotive parts sto
https://www.ebay.com/itm/322919230951
My soft jaw pliers came with an ITT Cannon circular connector kit. I
have three with different tubing diameters.
https://www.google.com/search?q=cannon+connector+pliers&tbm=isch
However, they're quite expensive from Cannon, so I would get something
cheaper:
https://www.google.com/search?q=soft+jaw+pliers&tbm=isch
Someone sells plastic covers that slide over the jaws to convert
channel locks into soft jaw pliers. Avoid. They don't work very
well.

147 hardware stores in Stockholm:
https://www.yelp.com/search?cflt=hardware&find_loc=Stockholm

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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  #12  
Old July 8th 18, 05:10 PM posted to rec.bicycles.tech
SMS
external usenet poster
 
Posts: 8,246
Default drill/tap in frames

On 7/7/2018 4:08 PM, Emanuel Berg wrote:
Jeff Liebermann wrote:

The tubing is probably too thin for threading
the hole. You need at least 3 full threads
wall thickness tubing to keep the mounting
screw from stripping the threads out of the
hole. For an M5x0.8, that's 0.8 mm per
thread. So, the minimum tubing wall thickness
would be 2.4mm. However, since the tubing on
your bicycle is probably around 0.5mm wall
thickness, the tubing wall will never be
thick enough to support threading. To get
more threads to grip is one reason why
builders use braze on bosses for
mount points.


I keep hearing this, but it isn't the case for
my bikes which have chainguards.

These have three stays, and of those, two are
mounted on the bike frame with M5 screws.
Threaded hole, no nut on the other side!

Then the chainguard is mounted on the stays,
likewise with M5s, threaded holes (only here
sometimes there are nuts as well).

The stays are about 1mm. How thick the frame
tube wall is I don't know, but I can take
a discarded frame and cut it with an angle
grinder to find out, God willing.

This ain't to say that rivnuts ain't a good
idea, of course.

BTW, do you by them online? I don't think they
are in our HW stores... (which is common with
the stuff you guys mention: durometer, soft jaw
pliers, etc.)


In my area you can by them over the counter at a fastener company
(http://olander.com/). Probably few, if any, hardware stores carry them.

  #13  
Old July 8th 18, 07:25 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 866
Default drill/tap in frames

sms wrote:

In my area you can by them over the counter
at a fastener company (http://olander.com/).
Probably few, if any, hardware stores
carry them.


Ain't it the truth!

I always said the hardware store were
overrated, save for the hot chics in their
early and mid 20s that works there, which BTW
is a capitalist trick so that there won't be
a prestige contest who supposedly knows more,
and the relaxed and content customers will buy
even more.

--
underground experts united
http://user.it.uu.se/~embe8573
  #14  
Old July 8th 18, 08:52 PM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 2,800
Default drill/tap in frames

On Sun, 8 Jul 2018 09:10:49 -0700, sms
wrote:

In my area you can by them over the counter at a fastener company
(http://olander.com/). Probably few, if any, hardware stores carry them.


Fastenal also carries Rivnuts:
https://www.fastenal.com/product/fasteners/rivets/rivet-nuts/602457?categoryId=602457&level=3
Nearest stores are probably in Mtn View and Santa Clara.



--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #15  
Old July 8th 18, 11:47 PM posted to rec.bicycles.tech
Doug Cimperman
external usenet poster
 
Posts: 131
Default drill/tap in frames

On 7/7/2018 6:00 PM, Emanuel Berg wrote:
Doug Cimperman wrote:

1) A drill press w/vise will work far better
than a hand drill. If you use a hand drill
in thicker (1mm) metal, the bits will go
dull really fast and tend to break as they
come out the back side of the hole.


Drill bits, is there a reason to use those
instead of just drills (round)?

I am not sure what you mean by drill bits not being round?

Drill bits with hex or triangle shanks tend to break if they snag in
metal. It is better to use a smooth-shank drill bit since if it snags,
it will just spin in the chuck instead of breaking.

As I understand it, "drill" is the term for the entire tool--either
hand-held, or bench- or floor-standing.

A "drill bit" is the part that actually makes the hole:
https://www.mcmaster.com/#30565a274/=1dmner9 (5.2mm, $2.89 each)

I must admit that I kinda prefer buying drills elsewhere... McMaster is
fast & easy but they usually do not say what brand you are getting. For
HSS drills and taps I usually buy the Hertel brand at MSC:
https://www.mscdirect.com/product/details/01076504 (5.2mm, $2.91)


  #16  
Old July 9th 18, 03:31 AM posted to rec.bicycles.tech
SMS
external usenet poster
 
Posts: 8,246
Default drill/tap in frames

On 7/7/2018 7:27 AM, Emanuel Berg wrote:
Are there any secrets to drilling holes in
steel bike frames? I have a couple of discarded
ones I can test on but I thought I'd
ask anyway.

Do you use normal power hand tools like
a drill-screwdriver and/or a drill press (if
possible with the desired bolt position)?

Do the normal rules apply, e.g. to get
a threaded hole for an M6, you first drill with
a 5.0mm drill?

And you can use chainsaw oil, right?


As Jobst Brandt stated: "I don't know many riders who believe that
drilling a hole in a frame tube is a reasonable concept."

  #17  
Old July 9th 18, 08:44 AM posted to rec.bicycles.tech
John B. Slocomb
external usenet poster
 
Posts: 73
Default drill/tap in frames

On Sun, 8 Jul 2018 09:10:49 -0700, sms
wrote:

On 7/7/2018 4:08 PM, Emanuel Berg wrote:
Jeff Liebermann wrote:

The tubing is probably too thin for threading
the hole. You need at least 3 full threads
wall thickness tubing to keep the mounting
screw from stripping the threads out of the
hole. For an M5x0.8, that's 0.8 mm per
thread. So, the minimum tubing wall thickness
would be 2.4mm. However, since the tubing on
your bicycle is probably around 0.5mm wall
thickness, the tubing wall will never be
thick enough to support threading. To get
more threads to grip is one reason why
builders use braze on bosses for
mount points.



It depends a lot on what the tube set is design for. A top tier road
bike (steel) will likely have tubes in the 0.5 - 1 mm thickness range.
Spirit - a top of the line triple butted frame set with oversized
tubes will be (top tube) 31mm O.D., and wall thickness of 0.5 - 0.38 -
0.5mm.

Steel frames traditionally use a small threaded boss soldered on where
the screw is required and other materials often use a "Rivnut", which
before anyone starts to disparage them should understand that they
were originally designed to provide blind holes in aircraft structure
and used literally by the millions. Successfully :-)






I keep hearing this, but it isn't the case for
my bikes which have chainguards.

These have three stays, and of those, two are
mounted on the bike frame with M5 screws.
Threaded hole, no nut on the other side!

Then the chainguard is mounted on the stays,
likewise with M5s, threaded holes (only here
sometimes there are nuts as well).

The stays are about 1mm. How thick the frame
tube wall is I don't know, but I can take
a discarded frame and cut it with an angle
grinder to find out, God willing.


The normal engaged thread length depends on the diameter of the bolt
and the "standard" (strength) For example, an M5 screw (grade 6h/6g)
will have a minimum stressed (threaded)area some 4.0103 mm long.
This is usually felt to be a sufficient thread engagement to provide
some 100% of shank strength. There are innumerable tables available
giving the required data.

This ain't to say that rivnuts ain't a good
idea, of course.

BTW, do you by them online? I don't think they
are in our HW stores... (which is common with
the stuff you guys mention: durometer, soft jaw
pliers, etc.)


In my area you can by them over the counter at a fastener company
(http://olander.com/). Probably few, if any, hardware stores carry them.

--
Cheers,

John B.


  #18  
Old July 9th 18, 03:03 PM posted to rec.bicycles.tech
dave[_3_]
external usenet poster
 
Posts: 38
Default drill/tap in frames

On Sat, 07 Jul 2018 17:54:40 +0200, Emanuel Berg wrote:

AMuzi wrote:

Subtract pitch from major diameter, e.g., tap drill for an m5x0.8 is
4.2mm


Well, then you still have to look up the pitch,
which is in the same table as the drill diameter, all of which is faster
than the thread gauge...

Yes use chainsaw oil on your chainsaw.


Won't that trigger a dangerous chain reaction?


I saw what you did there.



--
davethedave
  #19  
Old July 9th 18, 05:21 PM posted to rec.bicycles.tech
David Scheidt
external usenet poster
 
Posts: 1,241
Default drill/tap in frames

sms wrote:
:On 7/7/2018 7:27 AM, Emanuel Berg wrote:
: Are there any secrets to drilling holes in
: steel bike frames? I have a couple of discarded
: ones I can test on but I thought I'd
: ask anyway.
:
: Do you use normal power hand tools like
: a drill-screwdriver and/or a drill press (if
: possible with the desired bolt position)?
:
: Do the normal rules apply, e.g. to get
: a threaded hole for an M6, you first drill with
: a 5.0mm drill?
:
: And you can use chainsaw oil, right?

:As Jobst Brandt stated: "I don't know many riders who believe that
:drilling a hole in a frame tube is a reasonable concept."

Who cares what riders think, what do the egineers do?


--
sig 47
  #20  
Old July 9th 18, 06:55 PM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 2,800
Default drill/tap in frames

On Mon, 9 Jul 2018 16:21:43 +0000 (UTC), David Scheidt
wrote:

sms wrote:
:On 7/7/2018 7:27 AM, Emanuel Berg wrote:
: Are there any secrets to drilling holes in
: steel bike frames? I have a couple of discarded
: ones I can test on but I thought I'd
: ask anyway.
:
: Do you use normal power hand tools like
: a drill-screwdriver and/or a drill press (if
: possible with the desired bolt position)?
:
: Do the normal rules apply, e.g. to get
: a threaded hole for an M6, you first drill with
: a 5.0mm drill?
:
: And you can use chainsaw oil, right?

:As Jobst Brandt stated: "I don't know many riders who believe that
:drilling a hole in a frame tube is a reasonable concept."


Who cares what riders think, what do the egineers do?


Jobst Brandt was a mechanical engineer.
https://en.wikipedia.org/wiki/Jobst_Brandt

What's an egineer?

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 




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