Most common drill bits to use for the most common taps?

[Pcmaker]

Which tap sizes are used the most and which drill bits do you need to tap the threads? I'm going to buy packs of cobalt drill bits from Amazon since they're not so expensive over there. The ones I've seen are metric for some reason.

 

[ELHEAD]

Hey , Pc Just google tap drill chart . You should find one you can download, or print pdf.
Dave

 

[JimDawson]

I like the Harbor Freight 115 piece cobalt drill set. About $120 full price, but wait for a 20 or 25% off coupon. That will cover all of the tap sizes from #0 to 1/2 inch. They are actually high quality drill bits, made in Russia I think.

For taps, it depends on what you are doing, but I use 10-24, 1/4-20, and 3/8-16 the most. Buy good taps, I normally buy spiral point taps from Fastenal. Have had really good luck with those. I think Fastenal sells OSG taps with their label on them.

 

[royesses]

Here are two good tap drill charts from LMS with 50% and 70% tap drill listings and clearance hole drill listings in metric and US fractional sizes. You can choose the sizes you would use the most. I have the HF cobalt drill set that Jim Dawson likes and it is really good. I also have metric drills in.1mm increments for 1 to 5mm and .5mm increments from 5mm to 13mm. They can get expensive. I also have screw machine length sets for use in close quarters work or try to get a closer approximation of a round hole. It takes a while to accumulate all the drill bits you may eventually need or want.
You may need letter drills or number drills which are in the HF cobalt set.

Roy

 

[markba633csi]

I use the smaller sizes a lot: 4-40 to 10-32 and metric from 6mm to 10mm
I have a number drill set, a letter set and a fractional set (but I didn't buy them all at once)
mark

 

[BaronJ]

Hi Guys,

Maybe you already know this, if you are stuck for a particular drill size, go to a slightly larger drill. For instance for M9 you need 8.4 mm, but 8.5 is a standard size. That LMS table is nice because it lists both 70% and 50% tapping drill sizes. Don't go below 50% thread engagement if you can avoid it. This becomes more important with smaller sizes. You are less likely to break a tap if the hole is larger.

 

[Mitch Alsup]

I like the Harbor Freight 115 piece cobalt drill set. About $120 full price,

This is the set of drills to have:: a) cobalt drills b) at lower than HSS prices.

 

[Creativechipper]

I picked up 115 Pc set off amazon ..https://www.amazon.com/gp/product/B011BEQ7GE/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
and they were defective, had dull points and crackle finish.
Once I sent pics over to the seller they said refund and keep the bits. I guess I wasnt being too picky being my old used bits look better. The one 1/2" silver bit is an old black and decker bit used for comparison.

 

[PT Doc]

I picked up 115 Pc set off amazon ..https://www.amazon.com/gp/product/B011BEQ7GE/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
and they were defective, had dull points and crackle finish.
Once I sent pics over to the seller they said refund and keep the bits. I guess I wasnt being too picky being my old used bits look better. The one 1/2" silver bit is an old black and decker bit used for comparison.

Should have purchased a quality set from HF.

 

[Creativechipper]

I think I will go to HF and inspect them 1st after this set I got blind..lol

I couldn't believe how bad of a finish and dull plus plating issues too.

So a good set of HF cobalt drill bits vs titanium bits should be good?