Greymage
Enlightened
I'd like to use the FF two-stage switch in some Arc twisties. I can drill a hole, but how do I make the threads? Can anyone post a link to a thread maker or whatever you call those things that let you make threads in something?
How do I make threads?
- Thread starter Greymage
- Start date
wasabe64
Flashaholic*
[ QUOTE ]
DSpeck said:
... you would have to tap afre drilling. It is a standard 2-56 thread. The screw used is a stainless steel button head cap screw, which Wayne sells in a kit with the boards and an Allen key (hex wrench).
[/ QUOTE ]
DSpeck said:
... you would have to tap afre drilling. It is a standard 2-56 thread. The screw used is a stainless steel button head cap screw, which Wayne sells in a kit with the boards and an Allen key (hex wrench).
[/ QUOTE ]
Greymage
Enlightened
A tap, that's what they're called! /ubbthreads/images/graemlins/ohgeez.gif Thanks.
jtice
Flashaholic
Greymage,
Many places sell taps, Enco for one has alot of them.
BTW,
Anyone know where to get a text file, or excel sheet, or other,
that tells what size hole to drill for each tap size?
Thanks
Many places sell taps, Enco for one has alot of them.
BTW,
Anyone know where to get a text file, or excel sheet, or other,
that tells what size hole to drill for each tap size?
Thanks
jtice,
I have a mobileDB file in my palm with drill and tap sizes. I can export it as a .csv file. I tried opening it in Excel and Excel converts someof the fractional drills to dates before I can specify any format on the column. /ubbthreads/images/graemlins/frown.gif
Send me an e-mail and I can sent it to you if you want. It consists of letter, number, fractional and metric drills up to 1" . It gives metric equivilant and shows the tap drill for standard and metric taps. It does not have the clearance drill bit size.
I have a mobileDB file in my palm with drill and tap sizes. I can export it as a .csv file. I tried opening it in Excel and Excel converts someof the fractional drills to dates before I can specify any format on the column. /ubbthreads/images/graemlins/frown.gif
Send me an e-mail and I can sent it to you if you want. It consists of letter, number, fractional and metric drills up to 1" . It gives metric equivilant and shows the tap drill for standard and metric taps. It does not have the clearance drill bit size.
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Doug S
Flashlight Enthusiast
[ QUOTE ]
jtice said:
BTW,
Anyone know where to get a text file, or excel sheet, or other,
that tells what size hole to drill for each tap size?
Thanks
[/ QUOTE ]Here is an online reference. The links are about half way down the page
tap/clearance hole sizing
jtice said:
BTW,
Anyone know where to get a text file, or excel sheet, or other,
that tells what size hole to drill for each tap size?
Thanks
[/ QUOTE ]Here is an online reference. The links are about half way down the page
tap/clearance hole sizing
jtice
Flashaholic
ah, thanks alot Doug.
Now, if I find an Excel or text version to print out, I am SET ! /ubbthreads/images/graemlins/smile.gif
Don, I saw that MobileDB pocket pc one too ! /ubbthreads/images/graemlins/smile.gif
I just didnt want to pay for MobileDB,,, is that program worth it?
Seems to be alot of files out there for it.
I think you should be able to get it to format correctly,,, you can make the excel sheet first, before importing it,,, i think.
Email on the way.
Now, if I find an Excel or text version to print out, I am SET ! /ubbthreads/images/graemlins/smile.gif
Don, I saw that MobileDB pocket pc one too ! /ubbthreads/images/graemlins/smile.gif
I just didnt want to pay for MobileDB,,, is that program worth it?
Seems to be alot of files out there for it.
I think you should be able to get it to format correctly,,, you can make the excel sheet first, before importing it,,, i think.
Email on the way.
wasabe64
Flashaholic*
Don, have you tried importing the .csv file into Access?
If you don't mind sending the file to me, I would more than happy to have a look at it (and make a copy for myself). /ubbthreads/images/graemlins/naughty.gif
If you don't mind sending the file to me, I would more than happy to have a look at it (and make a copy for myself). /ubbthreads/images/graemlins/naughty.gif
PEU
Flashlight Enthusiast
wasabe64,
No need or time at the moment.
PEU, .csv file coming at you; the mdb file is in laptop which is currently not on.
If this is something that others want, I can upload it to my web site later and provide a link to it.
No need or time at the moment.
PEU, .csv file coming at you; the mdb file is in laptop which is currently not on.
If this is something that others want, I can upload it to my web site later and provide a link to it.
tvodrd
*Flashaholic* ,
Chart in front of me says to use a #50 (.070" dia) drill for the #2-56 tap which is used in the firefly and my CR2 design.
Larry
Larry
idleprocess
Flashaholic
I have an Excel spreadsheet for common tap drill sizes at work. I know I went as small as 2-56 on it, but it's even-numbered sizes only, 2-12, with a few fractional sizes.
While on the subject of tapping holes, I would like to point out something I learned quite a while ago when I worked for an aerospace fastener manufacturer. Your pilot hole for the tap is selected based on a certain percentage of thread engagement. This would be easier to explain with pictures but I'm too lazy to go to that extent. /ubbthreads/images/graemlins/tongue.gif
Ultimate failure of a fastener will depend not only on the loads exerted as well as other forces but on the direction of the load as well. The threads are used to keep the fastener in place under loads of tension, for the most part. When the fastener and the parent material are the same, the cylinder of shear where the threads will fail is roughly at 50% of the thread; that is to say half way between the root of the fasteners thread and the root of the tapped thread. In a case where the fastener has a considerably higher tensile strength than the parent material, the shear will occur much closer to the root of the thread in the parent material. My point? In the case of tapped holes in materials like aluminum, The fastener would shear close to the root of the thread in the aluminum which means that a larger pilot hole would not effect the ultimate strength of the mechanical bond. This is important and a good thing to keep in mind because a larger pilot hole is easier to tap and those of us who have broken taps can appreciate this!
Ultimate failure of a fastener will depend not only on the loads exerted as well as other forces but on the direction of the load as well. The threads are used to keep the fastener in place under loads of tension, for the most part. When the fastener and the parent material are the same, the cylinder of shear where the threads will fail is roughly at 50% of the thread; that is to say half way between the root of the fasteners thread and the root of the tapped thread. In a case where the fastener has a considerably higher tensile strength than the parent material, the shear will occur much closer to the root of the thread in the parent material. My point? In the case of tapped holes in materials like aluminum, The fastener would shear close to the root of the thread in the aluminum which means that a larger pilot hole would not effect the ultimate strength of the mechanical bond. This is important and a good thing to keep in mind because a larger pilot hole is easier to tap and those of us who have broken taps can appreciate this!
Doug S
Flashlight Enthusiast
Good info, Don. Is it correct to interpret what you say to mean that for the case where the strength of the parent material does not exceed that of the fastener, there is little to be gained strenth-wise to exceeding 50% engagement?
Doug,
I am in over my head here but since the material will deform prior to shearing, I *believe* that 60% thread engagement is typically considered the minimum for materials of similar shear strengths. I am sure that there are some real engineers among us who can shed light on this. My main point was to consider the case of a relatively soft parent and the fact that the fastener need only sink its "teeth" slightly to be as strong in tension as if it had a full "bite". Another consideration for threads on our lights which join the component parts is that full thread engagement may not be necessary in terms of the strength and loads encountered. Perhaps some have noticed, for instance, on some of the older SF E bezels where the female thread that accepts the battery tube is barely more than a scratch in the surface. There are times when the thread overlap can be fudged to allow fit of parts and components that would not be possible if a "classic" thread were used. If one looks at the tail cap thread on the L1 or A2, you will notice that the profile is more of an Acme thread than a standard thread. With extra effort or special tooling, one can increase the pitch without needing the depth of overlap dictated by a conventional thread geometry.
Oh yeah, I opened the mdb file in access as suggested and then exported it to excel. For those who want it, it is available HERE (excel file for tap drill sizes) .
Some day, I want to append this file with the thread height of the various thread pitches. If I want to put a 28 pitch thread on a 5/8" OD tube, I want to know the required bore in the female part that I plan to screw on this. I know that this information can be gleamed from the machinists handbook but not readily by someone like myself who doesn't understand all of the conventions and defintions. /ubbthreads/images/graemlins/frown.gif
I am in over my head here but since the material will deform prior to shearing, I *believe* that 60% thread engagement is typically considered the minimum for materials of similar shear strengths. I am sure that there are some real engineers among us who can shed light on this. My main point was to consider the case of a relatively soft parent and the fact that the fastener need only sink its "teeth" slightly to be as strong in tension as if it had a full "bite". Another consideration for threads on our lights which join the component parts is that full thread engagement may not be necessary in terms of the strength and loads encountered. Perhaps some have noticed, for instance, on some of the older SF E bezels where the female thread that accepts the battery tube is barely more than a scratch in the surface. There are times when the thread overlap can be fudged to allow fit of parts and components that would not be possible if a "classic" thread were used. If one looks at the tail cap thread on the L1 or A2, you will notice that the profile is more of an Acme thread than a standard thread. With extra effort or special tooling, one can increase the pitch without needing the depth of overlap dictated by a conventional thread geometry.
Oh yeah, I opened the mdb file in access as suggested and then exported it to excel. For those who want it, it is available HERE (excel file for tap drill sizes) .
Some day, I want to append this file with the thread height of the various thread pitches. If I want to put a 28 pitch thread on a 5/8" OD tube, I want to know the required bore in the female part that I plan to screw on this. I know that this information can be gleamed from the machinists handbook but not readily by someone like myself who doesn't understand all of the conventions and defintions. /ubbthreads/images/graemlins/frown.gif
There's a whole chapter (100+ pages) in my Machinery's handbook on this subject. I'm paraphrasing some, but the following is from that handbook, 25th edition.
Often a 55 to 60 % thread is satisfactory, although 75% threads are commonly used to provide an extra margin of safety. In general, when the engagement length is more than 1-1/2 times the nominal diameter a 50-55% thread is satisfactory. The handbook then provides a table of tap drills and hole size limits and then several tables for different threads generally based on 75% of full thread depth. this formula is given for calculating the actual % of thread engagement:
Hole size= basic major diameter- (1.08253x%full thread / No. of threads per inch).
After that it goes into more detail, then into thread cutting and lathe setup, rolling threads, milling threads, and the necessary setup details. There appears to be enough detail for you to figure out how to do this for any size we might need for flashlights. Do like I did & buy the older edition for half price when a new one comes out.......
Often a 55 to 60 % thread is satisfactory, although 75% threads are commonly used to provide an extra margin of safety. In general, when the engagement length is more than 1-1/2 times the nominal diameter a 50-55% thread is satisfactory. The handbook then provides a table of tap drills and hole size limits and then several tables for different threads generally based on 75% of full thread depth. this formula is given for calculating the actual % of thread engagement:
Hole size= basic major diameter- (1.08253x%full thread / No. of threads per inch).
After that it goes into more detail, then into thread cutting and lathe setup, rolling threads, milling threads, and the necessary setup details. There appears to be enough detail for you to figure out how to do this for any size we might need for flashlights. Do like I did & buy the older edition for half price when a new one comes out.......
tvodrd
*Flashaholic* ,
For years I have just used the large chart on the shop wall. We know it's on the "tight" side and go the "next size up" when warranted. It calls for a #51 (.067") for a #2-56. The wall chart in my office is on the looser side and calls for a 5/64" (.0781) and claims "approx 65%", and after looking at (and printing) Wayne's bitchin chart, I suspect mine is in error! #2-56's are very easy to bink and for a case contact a #49 (.073) is probably most appropriate.
Larry
Larry
