# tap help



## aljsk8 (Sep 21, 2009)

simple question for you guys

i want to tap threads into holes for holding led stars down ive chosen 
M3x0.5 machine screws

from what ive read i need to drill 2.5mm holes which i have done
now i need to order the tap

i see that there are 1st 2nd and 3rd taps do i need all of these or just one?

thanks

Alex


----------



## precisionworks (Sep 21, 2009)

> 1st 2nd and 3rd taps do i need all of these or just one?



You just need one, but there are at least six choices 

The three taps you refer to are called taper, plug & bottoming:

*TAPER TAPS* * have 8 to 10 threads chamfered for easy starting and are used for tough threading jobs.

*PLUG TAPS* * used for ordinary threading and have a 3 to 5-thread chamfer, or relief, at the point.

*BOTTOMING TAPS * * with their short chamfer (1 to 1-1/2 threads),are used where the thread must go to the bottom of the hole.


There are three other types of taps that often work better than the three listed above.


For through holes, a spiral point tap pushes the chips out of the hole ahead of the tap. They make through hole tapping fast & easy.


For blind holes, a spiral flute tap pushes the chips up (backwards) so the bottom of the blind hole stays clean. They are awesome for blind hole tapping.


Thread forming taps don't cut metal at all, but displace metal to form threads. They can be used in both through holes & blind holes.


----------



## wykeite (Sep 21, 2009)

As I see the OP is in the UK your terminology is a bit off Precisionworks. Over here the term plug and bottoming are interchangable, we refer to taper, second and usually plug. Also with some manufacturers the taper and second do not necessarily cut to full depth of thread though this is becoming increasingly rare. If it's through hole the answer is you'll probably get away with a taper but look for something of quality like a Dormer or Presto.


----------



## precisionworks (Sep 21, 2009)

> the OP is in the UK


Here's a thread former that should work well, and is located on the right side of the pond 

http://cgi.ebay.co.uk/Fluteless-Tap...in_3?hash=item2c4fcbabcd&_trksid=p3286.c0.m14

It looks like it's made by Dormer in Sweden.


----------



## aljsk8 (Sep 21, 2009)

ok that info helps a lot

ive been looking at very low cost ones is it that they wont last long or that they will actually produce a poor finish

i want good threads but i will probably only use this tool for 8 holes and then never again

as usual trying to complete project on a tight budget


----------



## wykeite (Sep 21, 2009)

precisionworks said:


> Here's a thread former that should work well, and is located on the right side of the pond
> 
> http://cgi.ebay.co.uk/Fluteless-Tap...in_3?hash=item2c4fcbabcd&_trksid=p3286.c0.m14
> 
> It looks like it's made by Dormer in Sweden.


 
The price though for a few holes. You could buy a full 3 tap HSS set for less than that, probably 2. One good set of taps at that size would last the average CPFer many years, you just have to remember where you put them. I know I have some somewhere. If I don't find them then they'll last a lifetime:thinking:.


----------



## gadget_lover (Sep 21, 2009)

Low cost taps USUALLY work OK, but they dull quickly or break. You should be able to get 8 holes out of cheap taps. Look for the CPF threads on tapping. There is a nice techique where you dril the hole and then (without moving anything) use the drill press to keep the tap lined up with the hole. That minimizes the chances of breaking.


Daniel


----------



## aljsk8 (Sep 22, 2009)

that would be great if i had a drill press

cordless drill and hand tools here!

will it make a difference that im tapping into copper?

thanks for all the advice guys


----------



## gadget_lover (Sep 22, 2009)

Copper is soft and will tap easily. 

I think you should use a lube with that. Probably WD40 would work, just to keep it from binding.

Dan


----------



## wykeite (Sep 22, 2009)

Copper is one of the worst metals for machining due to it's high ductility. You'll get the best results using carbon steel taps as they are generally sharper than HSS and cut better in copper, cheaper too. Don't forget that you don't wind a tap straight through, go 3/4 turn, then back off the tap to break the chip then repeat. Use some lubricant too, if the tap starts to squeak back it out fully, it's telling you it's binding and going to break.


----------



## precisionworks (Sep 22, 2009)

Copper, like some types of aluminum, is gummy. A forming tap, like the Dormer referenced above, would be my first choice.



> best results using carbon steel taps as they are generally sharper than HSS


Carbon taps are sharp, but HSS taps are much tougher & break less easily. A 3mm tap is delicate, no matter what you use. The forming tap, because it has no flutes, is the toughest. HSS is next, carbon steel is last. The only "benefit" of carbon steel is that they are dirt cheap.



> cordless drill and hand tools here!


Even though you have only a few holes to tap, each one has to be a perfect 90 degrees to the surface. Use a small square to guide the drill & to start the tap. If the tap is started the slightest bit tilted, it will bind & may break.


----------



## aljsk8 (Sep 23, 2009)

cheers guys im going to go for hss - the former would be nice but i dont have that kind of money for something ill probably never use again - ive spent all the money on the leds!

ill try to put into practice the things you have mensioned

not sure how to use a square to line it all up - do you mean have the thin part of the square pointing vertically then line the drill up with it by eye? and the same with the tap

i might see if i can find someone with a drill press. if someone could tell me the tapping procedure with a drill press or link me to some instructions that would be great


----------



## Atlascycle (Sep 23, 2009)

Get a block that is about 2/3's of the length of the tap tall and find someone with a drill press to drill your holes to be tapped and to also drill a hole in the block that is a slip fit for the tap and use the block as a guide to keep the tap straight.

I'll try to post a pic to help to explain what i am talking about.


Jason


----------



## precisionworks (Sep 23, 2009)

Photo of a tapping block:

http://www.finelinehair.com/home/taig_mill_carriage_mod_2.jpg


----------



## wykeite (Sep 23, 2009)

precisionworks said:


> Copper, like some types of aluminum, is gummy. A forming tap, like the Dormer referenced above, would be my first choice.
> 
> Carbon taps are sharp, but HSS taps are much tougher & break less easily. A 3mm tap is delicate, no matter what you use. The forming tap, because it has no flutes, is the toughest. HSS is next, carbon steel is last. The only "benefit" of carbon steel is that they are dirt cheap.
> 
> Even though you have only a few holes to tap, each one has to be a perfect 90 degrees to the surface. Use a small square to guide the drill & to start the tap. If the tap is started the slightest bit tilted, it will bind & may break.


 
A forming tap is of little benefit in this situation, it's hardly a high torque load so a cut thread is more than adequate. There also isn't the raised rim which would undesirable here.

HSS may well be tougher but it's also not as sharp and more likely to bind and break unless you have a 'feel' for tapping. 

I think also it's a good time to point out that a lubricant is necessary, every metal has a suitable lubricant but for such a small hole a bit of 3 in 1 or engine oil will work.


----------



## Torque1st (Sep 23, 2009)

Plain lubricating oils do not make good tapping fluid.

Try:
http://www.slideproducts.com/cgi-bin/product.cgi?skucat=404
Similar products can be found at your local industrial tool store. I have even heard milk can be used for tapping in copper. I have not tried it myself.

More info here:
http://www.practicalmachinist.com/vb/showthread.php/machining-copper-78223.html


----------



## precisionworks (Sep 23, 2009)

> I have even heard milk can be used for tapping in copper.


+1

The nice thing about milk or cream is that the small, single serve dispensers are free whey you buy a cup of coffee 



> Plain lubricating oils do not make good tapping fluid.


Engine oils work by keeping metallic parts separated by a microscopic layer of lubricant. In tapping, there is no metallic separation but rather extremely high pressure as the tap shears (cuts) metal ... or displaces the material with a forming tap. There's a can of Tap Magic at both drill presses, the mill and the lathe - which is why the gallon can is the best value if you do much drilling or tapping.


----------



## aljsk8 (Sep 24, 2009)

ok ive got one of you saying HSS and one saying carbon steel

im going to buy on monday which one should i get??

that block is a great idea ill probably have to make something from wood

ok im my shed i have

lithium grease - the orange stuff for cars
lithium grease - the white stuff for bearings
silicone spray
wd40
oil for garden tools
ptfe chain lube

in the kitchen i have

milk
butter
cream

in the bathroom i have 

baby oil :thumbsup:

so which should i use??


----------



## KC2IXE (Sep 24, 2009)

I'd go with a quality HSS tap - the price diference is small - If it's a through hole, ise what is called a "sprial point" (aka a 'GUN') tap - they do not break as easily as a 4 flute 'hand tap'

Of your choices of lube, I'd use the cream!!

That said - pick up a can of tapmagic etc - I'd normally say "grab some dark sulpher cutting oil" but they tend to REALLY discolor copper/copper alloys

BTW - cutting/tapping - for Aluminum, if you can get ORIGINAL Tapmagic for Aluminum or Original Formula Alumi-tap - grab it. The first is no longer made as far as I know, the second is, but can't be shipped to say, California - both are Chlorinated Hydrocarbons (aka Ozone layer depleaters), but boy do they WORK


----------



## saabluster (Sep 24, 2009)

aljsk8 said:


> cheers guys im going to go for hss - the former would be nice but i dont have that kind of money for something ill probably never use again - ive spent all the money on the leds!


The former is what you want. You may spend more money and time if you go the other route and end up breaking the bit off in the work. Then you will have to start over with a new piece of metal. Ask me how I know. The former is sooo much easier. The results are much better too as the threads are tighter.


----------



## aljsk8 (Sep 24, 2009)

all this to mount leds! why cant the adhesive be as good thermally as the compound!!!!

ive had a re-read through the comments and a bit on the internet

the former may cause the surface of the material to raise up around the hole (tiny amount)

but without sanding the surface this would raise the star up and harm thermal conductivity

i would preffer not to sand the surface as it is a machined copper heatsink

although i have very little experience i will be taking it very easy so i hope that helps

thanks for all the advice guys but i still dont have a clue what to get!


----------



## saabluster (Sep 24, 2009)

aljsk8 said:


> all this to mount leds! why cant the adhesive be as good thermally as the compound!!!!
> 
> ive had a re-read through the comments and a bit on the internet
> 
> ...


You will have to do worse than sanding if you break that bit off in the heatsink. You don't have to sand anyway. Use a countersink to clean up the raised portion. How thick is the metal?


----------



## aljsk8 (Sep 24, 2009)

ill have a look when i get home but id say about 5 or 6mm than fins one one side

the drill bit has pushed the fins aside so the tap will go straight through


----------



## saabluster (Sep 24, 2009)

aljsk8 said:


> ill have a look when i get home but id say about 5 or 6mm than fins one one side
> 
> the drill bit has pushed the fins aside so the tap will go straight through


That will be fine then. Just making sure there was enough material to countersink. I tap 3.2mm copper all the time for the DEFT. I started out with normal cutting taps back in the day and I can't tell you what a massive difference it makes to use the former. I broke the cutting taps left and right. When I found out about formers I bought three because of my experience with the other taps. I still haven't opened two of the boxes because the one is doing great. I can't stress enough how important it is to get the former.


----------



## wykeite (Sep 24, 2009)

Torque1st said:


> Plain lubricating oils do not make good tapping fluid.


 
Yes they do! I'm not talking pansy little 6mm threads. Try the 32mm thead I had to die nut today. Not only do you have the cutting action at the point of cut but you have the friction of the wedge, screw to you.

I have never broken a tap in my life. Anyone who has ever broken a tap has no feel for engineering and doesn't understand what they are doing.


----------



## aljsk8 (Sep 24, 2009)

ok i measured the thickness its actually only 3.5mm thick with 8mm high fins

im leaning toward the former based on your experience with copper
if you have snapped them then so will I

and the point is i dont know what im doing so I could snap them

everyone has to learn somewhere

my only problem with the former aside from cost is that it says 2.8mm drill
but i only have 2.5mm

where do i get drills that acurate? will i be ok with a 2.5mm hole?


----------



## saabluster (Sep 24, 2009)

aljsk8 said:


> everyone has to learn somewhere



Everyone except for Mr. "never broken a tap in my life" that is.



aljsk8 said:


> where do i get drills that acurate? will i be ok with a 2.5mm hole?


McMaster Carr. They have a very good site that will help you to see what you need and why.


----------



## Atlascycle (Sep 24, 2009)

wykeite said:


> Yes they do! I'm not talking pansy little 6mm threads. Try the 32mm thead I had to die nut today. Not only do you have the cutting action at the point of cut but you have the friction of the wedge, screw to you.
> 
> I have never broken a tap in my life. Anyone who has ever broken a tap has no feel for engineering and doesn't understand what they are doing.




you must not have tapped many holes if you have never broken a tap.....


----------



## precisionworks (Sep 24, 2009)

> I have never broken a tap in my life.


I also have never broken a tap, since I started using formers 



> Anyone who has ever broken a tap has no feel for engineering


I drill & tap, on average, 500 holes per month. Some as small as 1/2", or as big as 3/4". When you run a tap in at 400 rpm with a Tapmatic 90X, you lose a bit of feel for the increase in holes tapped per minute. The entire run of about 500 is tapped one after another after another - all I want to do is get it done & off the mill. Tap breakage was a fairly regular event when using cutting taps, even the best ones from OSG, Emuge, etc. I have yet to break the first former, but I have dulled a few - although it takes thousands of holes.

Lubrication is critical, which is why Tapmagic is sold in gallons and larger sizes. As cheap as most machine shop managers are, I have yet to see one use motor oil, baby oil, or olive oil as a tapping aid. Most oils are thin film, low pressure lubricants. Tapping fluids are extended pressure lubricants.


----------



## precisionworks (Sep 24, 2009)

> im going to buy on monday which one should i get??


See the forming tap on eBay Europe, post #4 in this thread.


----------



## KC2IXE (Sep 24, 2009)

wykeite said:


> ...snip...I have never broken a tap in my life. Anyone who has ever broken a tap has no feel for engineering and doesn't understand what they are doing.



Guess you've never had to tap a #6-32 tap on the top of a 15ft step ladder, on a poorly mounted part (aka it tended to move) when it's 5 degrees outside, and you're wearing gloves. That's what I was doing the last time I broke a tap! - 8 hours of work to pull the item that was getting tapped down to ground level, 10 minutes to remove the broken tap, 1-2 minutes to finish tapping the hole, and about 6 hours to put the part back. It was a VERY expensive broken tap (grumble)

Tapping on a bench/in a machine is fairly simple. You'll break taps if you get lazy, or worse, try to use the tap beyond it's life span. They ARE cutting tools, and they DO wear out


----------



## saabluster (Sep 24, 2009)

Seems there are a few people around here who have no feel for engineering and don't understand what they are doing. We should all just quit since we are so pathetic.:shakehead


----------



## LukeA (Sep 24, 2009)

wykeite said:


> Yes they do! I'm not talking pansy little 6mm threads. Try the 32mm thead I had to die nut today. Not only do you have the cutting action at the point of cut but you have the friction of the wedge, screw to you.
> 
> I have never broken a tap in my life. Anyone who has ever broken a tap has no feel for engineering and doesn't understand what they are doing.



It's harder to break larger taps than smaller ones. If you're hand-tapping with a 32mm tap, I wouldn't be surprised if you never broke the tap. 

It's the properties of scaling. A tap of diameter twice that of another has four times the cross sectional area, which gives it four times the strength. Say you also use with that tap a wrench twice as long as the one you would use for the smaller tap. That wrench allows you to apply twice as much torque as the smaller one. So, when you increase the size of the system by a factor of two, you apply twice as much force to a tap that's four times as strong. It works the other way as well, decrease the system by a factor of three and you are applying 1/3 the force to a tap that's only 1/9 as strong.

In short, bigger taps are harder to break.


----------



## aljsk8 (Sep 25, 2009)

Ok guys lets all :grouphug:

right ive found a HSS thread former for about a 3rd of the price of the ebay dormer one

is it ok that its lower cost as its a former and should be stronger anyway

here is the site they are near the bottom

http://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Taps

also i see that 7/64" is the right size bit to use and i can get one of those no problem


----------



## precisionworks (Sep 25, 2009)

> 060-085-00100 HSS M3x0.5 Thread Forming Tap £4.75


Even if it isn't Dormer quality, it is at least many times tougher & stronger than any thread cutting tap. Half the battle is choosing the correct tool 



> 7/64" is the right size bit to use


Formers use a different (larger) drill size than cutting taps, as no metal is being taken out of the hole.


----------



## modamag (Sep 25, 2009)

If you're gonna go ebay route take a look at some of the OSG a spiral point and spiral flute taps. Once you use these you'll never go back to the traditional taper/bottoming taps.


----------



## Bruceter (Sep 25, 2009)

wykeite said:


> I have never broken a tap in my life. Anyone who has ever broken a tap has no feel for engineering and doesn't understand what they are doing.



Never worked in a production machine shop have you?

Bruceter


----------



## saabluster (Sep 26, 2009)

Bruceter said:


> Never worked in a production machine shop have you?
> 
> Bruceter


We're supposed to be :grouphug:ing right now.


----------



## gadget_lover (Sep 26, 2009)

wykeite said:


> I have never broken a tap in my life. Anyone who has ever broken a tap has no feel for engineering and doesn't understand what they are doing.



While I'm sure that you can be a great engineer (like my dad, a mechanical and civil engineer) and still break taps (like my dad), the basic truth is that it's all about technique. If you don't stop to think about the forces involved, it's easy to break them.

I'm neither a machinist nor an engineer. I occasionally had to tap holes, and I broke taps occasionally. My basic problem was simple. I was under the impression that a tap would follow the hole. From that I figured if the hole was straight up and down, the tap would make threads the same way. I had no need of tapping jigs, blocks or other helpers.

Unfortunately, that is dead wrong. Taps will sometimes follow the hole, sometimes not. When they don't, they tend to bind and break as the forces end up uneven.

Using any alignment guide is a great idea.

BTW, I broke a tap in a perfectly drilled, lubed and straight hole in a large iron casting. The tap was properly aligned and did a great job until it came out the other side. I did not realize that on the other side was a support web, and my hole was 1/3 in the web and 2/3 empty space. That bent the tap sideways and it snapped, the end pinging across the room.

Yup. You can understand the right ways and do everything right and still break the darn things.

Daniel


----------



## aljsk8 (Oct 9, 2009)

Just to let eveyone know i got a M3 former (that rolls the thread) and the 8 holes were tapped flawlessly. i used a drill press and then a homemode square to get it all alligned

thanks for all the help

the 2500 lumen flood light is well on its way to compleation


----------



## saabluster (Oct 9, 2009)

aljsk8 said:


> Just to let eveyone know i got a M3 former (that rolls the thread) and the 8 holes were tapped flawlessly. i used a drill press and then a homemode square to get it all alligned
> 
> thanks for all the help
> 
> the 2500 lumen flood light is well on its way to compleation


----------



## StrikerDown (Oct 9, 2009)

oops!


----------

