forgot to mention - the oil don't have to be cutting oil (the one used when machining steel), i'm using silicone oil when cutting threads to aluminium, but any oil would do the job for aluminium (except vegetable oils )
so basically this is all you need:
Those 3 taps are the same tap...the different taps are Taper, Plug and Bottoming. In softer materials you could really start with the bottoming and use that only as long as you start it straight. Taper taps just have a much longer lead in to help start the tap parallel to the hole, plug are common as they are a compromise of both.
those 3 taps are definitely NOT THE SAME TAP ! those are for progressive taping - you go with the "single strip first", then "double strip" and then the "no strip" each one is cutting he groove deeper and deeper. - to cut precise thread you have to do it progressively.
forgot to mention - the oil don't have to be cutting oil (the one used when machining steel), i'm using silicone oil when cutting threads to aluminium, but any oil would do the job for aluminium (except vegetable oils )
so basically this is all you need:
Those 3 taps are the same tap...the different taps are Taper, Plug and Bottoming. In softer materials you could really start with the bottoming and use that only as long as you start it straight. Taper taps just have a much longer lead in to help start the tap parallel to the hole, plug are common as they are a compromise of both.
those 3 taps are definitely NOT THE SAME TAP ! those are for progressive taping - you go with the "single strip first", then "double strip" and then the "no strip" each one is cutting he groove deeper and deeper. - to cut precise thread you have to do it progressively.
Uh no, those stripes identify the tap and you do not have to use all 3 to do a thread. Single is suppose to be TAPER tap, Double is PLUG tap, None is BOTTOMING. Really has nothing to do with the thread itself, you will have a hard time aligning a BOTTOMING tap in a plain hole to start it. That is what the TAPER tap is for, it has a very long taper at the front to allow it to guide itself into the hole. This TAPER tap is fine for almost all situations, the only time you move to the other taps if you want to cut FULL threads to the bottom of a blind hole. In fact, TAPER isn't that common since a PLUG can really do the same thing.
Did you buy your taps from China? Every tap looks exactly the same, the taper on all of them appears the same and the last tap with no stripe on it is certainly not a BOTTOMING tap because it has a point on it.
Look at the picture
Uh no, those stripes identify the tap and you do not have to use all 3 to do a thread. Single is suppose to be TAPER tap, Double is PLUG tap, None is BOTTOMING. Really has nothing to do with the thread itself, you will have a hard time aligning a BOTTOMING tap in a plain hole to start it. That is what the TAPER tap is for, it has a very long taper at the front to allow it to guide itself into the hole. This TAPER tap is fine for almost all situations, the only time you move to the other taps if you want to cut FULL threads to the bottom of a blind hole. In fact, TAPER isn't that common since a PLUG can really do the same thing.
Did you buy your taps from China? Every tap looks exactly the same, the taper on all of them appears the same and the last tap with no stripe on it is certainly not a BOTTOMING tap because it has a point on it.
Look at the picture
Uh no, those stripes identify the tap and you do not have to use all 3 to do a thread. Single is suppose to be TAPER tap, Double is PLUG tap, None is BOTTOMING. Really has nothing to do with the thread itself, you will have a hard time aligning a BOTTOMING tap in a plain hole to start it. That is what the TAPER tap is for, it has a very long taper at the front to allow it to guide itself into the hole. This TAPER tap is fine for almost all situations, the only time you move to the other taps if you want to cut FULL threads to the bottom of a blind hole. In fact, TAPER isn't that common since a PLUG can really do the same thing.
Did you buy your taps from China? Every tap looks exactly the same, the taper on all of them appears the same and the last tap with no stripe on it is certainly not a BOTTOMING tap because it has a point on it.
Look at the picture
even your picture is showing the same as i mentioned - note the progressing sharpens of the cutting edges from left to right and the increasing depth of the groove - so it's a set of 3 taps for progressive taping. (1 strip, 2strips, finish with no strip) - but those are the ones for taping blind holes
i never said my taps are bottoming - mine are through hole.
=== edit - forgot to comment on china
no, i'm not buying machining tools from China . i'm buying those (taps, drill bits, milling bits, cutting disks) in local hardware stores , because those machining tools from china are just toys
'progressive tapping' is an exercise in time wasting for normal applications.
For simply putting an M3 thread in a piece of aluminium, or even mild steel, to hold the minimal torque required for mounting components or covers, a plug tap is the only tap you need. That is the middle one, if you've missed that point.
'progressive tapping' is an exercise in time wasting for normal applications.
For simply putting an M3 thread in a piece of aluminium, or even mild steel, to hold the minimal torque required for mounting components or covers, a plug tap is the only tap you need. That is the middle one, if you've missed that point.
let me disagree - either you use all 3 of them or you have to use a different single-pass tap (which is more like the last one - without strips) . otherwise your threads will be out of spec (if talking about correct taping/cutting thread)
if you want just screw it "somehow" together - then as others suggested - just skip the taping (gave it a shot in the meantime... well... i'm not impressed thread on the screw flattened, but there are some kind of a grooves in the hole... it was a exercise to screw it in... it withstands a little bit of force... but i wouldn't recommend that )
using just the middle tap only is something in between - but it's better than not taping at all. i will rather keep spending the extra 1 minute to tap it correctly - use all 3 in the set
'progressive tapping' is an exercise in time wasting for normal applications.
For simply putting an M3 thread in a piece of aluminium, or even mild steel, to hold the minimal torque required for mounting components or covers, a plug tap is the only tap you need. That is the middle one, if you've missed that point.
let me disagree - either you use all 3 of them or you have to use a different single-pass tap (which is more like the last one - without strips) . otherwise your threads will be out of spec (if talking about correct taping/cutting thread)
if you want just screw it "somehow" together - then as others suggested - just skip the taping (gave it a shot in the meantime... well... i'm not impressed thread on the screw flattened, but there are some kind of a grooves in the hole... it was a exercise to screw it in... it withstands a little bit of force... but i wouldn't recommend that )
using just the middle tap only is something in between - but it's better than not taping at all. i will rather keep spending the extra 1 minute to tap it correctly - use all 3 in the set
Your taps are odd, sorry to say. Normal plug taps will fully form the thread, only the first few turns are tapered down.
What I said was that ALL 3 of your taps look exactly the same from the tip to the taper. None of the tapers appear to change. Those stripes have nothing to do with the H limit or class of fit. You are just wasting your time running all 3 taps through and in a blind hole they will do no different unless they do in fact have a differing tip taper between the 3 which it appears they do not.
once again and slowly.... I'm using those to cut threads - each pass is CUTTING DEEPER INTO THE WALLS OF THE HOLE and is producing chips ....
if you think the TIP of the taping tool has anything to do with the thread cutting/taping process then you're wrong. the tip of the tool got one job - center the tool in the hole at the beginning. the shape of the tip has nothing to do with the cutting edges of the tool.
put
mrpete222 tap
into youtube search and you'll get more advice than you ever need on tapping.
Those serial taps are not very common in North America. My handy catalogue has 25 pages of various styles of taps but not one set of serial taps. I've been meaning to get a set because I do a lot of hand tapping stainless and I thought they'd help, but finding them in inch sizes is very difficult
2) Drill a 2.5mm hole, countersink the top a little bit, then use the hand tool. the intermediate one to slowly cut the threads using some lubrication in the process. If it gets too tough reverse out to remove debris and try again.
4) Chinese tools are generally badly made, and I bought this one in the picture - Not sure if this is starting, intermediate or bottoming.
5) How on earth do you drill a perfect 2.5 mm hole? I have a drill press, but am not sure it will cut a good hole, I mean the drill bit has to be perfect, the drill chuck perfectly balanced we are talking Rolls Royce engine quality needed here else it will be a triangular and larger than needed hole, am I right?
An unbelievable amount of detail for what I had thought was a simple question. So I deduce that:
1) aluminium is soft enough to force a M3 screw into a 2.7mm hole without prior tapping. Noone has mentioned the thickness of the aluminium here, I presume this holds true for a 1.2mm of aluminium but maybe not so true for drilling into a solid heatsink with thickness of 5mm or more? Anyway I do not think I want to try it.
2) Drill a 2.5mm hole, countersink the top a little bit, then use the hand tool. the intermediate one to slowly cut the threads using some lubrication in the process. If it gets too tough reverse out to remove debris and try again.
3) three general types of tap bits, for starting, continuing and finishing (bottoming) a (blind) hole. For a through hole the intermediate is just fine.
4) Chinese tools are generally badly made, and I bought this one in the picture - Not sure if this is starting, intermediate or bottoming.
5) How on earth do you drill a perfect 2.5 mm hole? I have a drill press, but am not sure it will cut a good hole, I mean the drill bit has to be perfect, the drill chuck perfectly balanced we are talking Rolls Royce engine quality needed here else it will be a triangular and larger than needed hole, am I right?
Now you can argue all you want but have a look at this set for instance which in dutch clearly states "first, middle and last tick" which is exactly how you should use them in tough material