Drill bits

What is everybody using for drill bits. We are struggling to find descent bits for a descent price. I have found that high school students are not real easy on tools especially anything consumable. (shocking right). We don’t want to spend a lot of money on bits that get trashed but the cheapy’s are not cutting it. (no pun intended)

We typically just buy “jobber” bits individually from McMaster Carr in the sizes we need. We buy at least half a dozen of each size that we use (3-5 sizes), that way if some get broken/lost/dull we always have more.

We do have some drill bit sets, but they don’t get used as much as the most common sizes.


We do the same.

Jobber Length
10X #9
5X 17/64
2X 10-32 Pre-Tap
2X 1/4-20 Pre-Tap

Stub Length
2X #9
2X 17/64

Extra Long
1X #9
1X 17/64


Life is too short to use cheap drill bits. :slight_smile: We do the same as above. You can buy the uncoated ones. They tend to break or get lost before the increase longevity of the coating becomes important. Either jobber length or stubby are the best. Stubbies being shorter tend to snap less. I keep a full index of quality bits put up for when other sizes are needed.

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Check this thread out

I order individuals of all the ubiquitous tools from mcmaster. In the past I had made little kits, and color coded the tools based on the size machine screw it is for. For example yellow painted tools were for 1/4" fastners: 5/32 allen keys, 7/16 wrenches/sockets, 9/32 drill bits

We buy bits from McMaster, spend some quality time teaching kids how to drill properly, and picked up a drill doctor. I agree with @FrankJ, life is too short for cheap drill bits, or any other consumable frankly.

You might find that kids will start respecting their tools more when you don’t just hand them a replacement but instead they have to spend some time resharpening bits they abuse.


Do these actually work as well as I hope?

What is pre tap?

With a little practice (5-20 minutes) it worked wonderfully for me. From ‘I can’t even drill this piece of steel’ to ‘weeee and we’re done!’

I cannot emphasize enough that one must follow the directions exactly. When my kids do not follow the instructions exactly the results are a calamity. But the penalty of failure so far has been low - just need to redo the sharpening between 1 and 4 times.

Edit - I have one for my garage shop too and I love it.


That’s the size to use before tapping a hole for the thread size indicated. It’s usually some really odd size.

This is referred to as the ‘tap drill size’ most commonly. To be nice and clear one might also include the % of thread depth the tap drill leaves.


75% thread is common in aluminum and plastics. Steels and titanium often go as low as 50%.

But now we’re off on a tangent…

The Vex posters that came in the KOP has the drill sizes, both tap and clearance for the common FRC screws. You can also google drill charts on your phone and find them quickly. It ends up being a mix of letter and number sizes because Americans are weird. Don’t get started on pipe and tube sizes. :slight_smile: Now we are really off topic.

Ah that’s what I thought. Just never heard of it referred to that way

We buy bulk 3/16" drill bits for our rivets.

We have carbide #11 (0.191") drill bits for our router (and sometimes bridgeport)

I think we got some off Flynn sci, some off dewalt, and some from ebay.

To us, they’re consumables. The cheap ones are good enough to drill some holes for some rivets. Anything precise is made on the router or bridgeport

Don’t worry. I’ve only hear it referred to as “Tap drill” as @JamesCH95 posted