Cheap CNC Router Bits on Amazon: A Risk You Shouldn't Take? 

The first 2 are upcut bits

The real explanation is that when the cutter gets hot it takes away the hardness of the cutter the metal therefore becomes softer. Great video.

For anyone who does not know how to determine if a cutting tool is made of carbide or high speed steel: 1. Carbide weighs about 80% more than the same volume of high speed steel. 2. Carbide is a duller grey color, whereas high speed steel is shiny. 3. Carbide, like "non-magnetic" stainless steels, is only slightly magnetic and will produce only a sight attraction, whereas high speed steel is strongly magnetic (an easy and cheap test). 4. High speed steel throws off a lot of bright yellow sparks when held against a grinding wheel, whereas carbide produces relatively few small sparks that are more of an orange hue. 5. An aluminum oxide stone will easily scratch the shank of a high speed still end mill or drill but will barely mark carbide. 6. Carbide is around 90 on the Rockwell C hardness scale, whereas high speed steel is about 65 on this scale (though few people have access to a hardness tester since a decent one costs $1600 to $1800). If a tool is cheap and does the job, then it doesn't matter what it is made of. Still, buyers of cutting tools should know how to tell the difference to avoid overpaying, as some of the high speed steel end mills / router bits (and other cutting tools) on Amazon claim to be made of, and priced as if they are, carbide. Caveat emptor.

1st, one would always break (no matter the price) whenever it was used for extended period of time since it is a (99% sure) HSS endmill designed for metal cutting here is why: - flutes are not as steep compared to woodworking endmills - That hole in back of that tool - "sharpness" of the tool. Even used or chipped carbide will feel sharper, it's harder than HSS - Tool marks. Most of the cheese grade HSS is just cut instead of ground. If you get your hand on a quality HSS tool, you will see a massive difference under microscope. Also, carbide is ALWAYS ground. - Discolouration of flutes. Carbide doesn't do it. At least not in woodworking. You will start fire before you discolour it. Change of appearance is due to material caking on it and/or tool chipping. Also, as you may notice, the whole tool is straw colour, which is produced when tool steel is tempered. The thing with HSS is it doesn't work well with high RPM - it gets hot, and you are essentially tempering steel, which leads to blunting and breaking. In metal working it is not a problem - turn on your coolant and that's it (of course within reason). In wood working well, 12k-18k RPM is a death sentence for those tools. 2nd and 3rd tools are actually carbide. How do I know? Tungsten carbide is a very poor heat conductor, and you state that "it's not even hot". I bet they also feel heavy in relation to their size. 2nd tool have good flute geometry for wood and non-ferrous metals. Only thing that is missing on that tool are polished surfaces (prevents chips sticking to it). I wasn't surprised that both of them didn't break. And I don't agree with your conclusion. Cheap carbide tools are good for general use - somehow manufacturers can't figure out how to make completely shitty carbide. Yea, if you are machining 714 Inconel or duplex, or you are using high feed endmill - quality will matter a lot. My advice for wood working would be: avoid HSS, get a tool with appropriate flute geometry, get high polish endmill (often found on tooling for aluminium) and lastly avoid coatings on cheap tools. Apply those advices in that order.

Loved this video. It helped a lot to approach bit selection! Thanks!

I believe that your speeds should change for the 3 flute vs 2 flute bits to keep the chip load correct. That might have caused some of the heat buildup in the first bit because it was spinning too fast.

Well you defiantly got me to subscribe ! I'm a newbie in the cnc arena and I was a little afraid that watching this video was going to tell me that I have to buy high dollar bits or walk away, but this was a pleasant surprise for sure. I know I'm going to crash the machine and break bits, but at those kind of prices I can still eat and sleep well without worry of breaking the bank in a new hobby. Great video ! I'm on board with you and will check out your other videos and look forward to more content. BTW, I'm 61 and hoping older dogs can learn new tricks...lol... Cheers and all the best from Utah !

We have bought almost all the brands on Amazon, the $40 $35 $24 $18, the best one we have been able to find after 4 years, it is a Chinese brand we had to buy to change from 1/4" to 6mm. We cut 25 sheets of plywood without changing bits , with the same cut. With the amana it reaches 5 sheets and loses the edge, there are some blue ones, it does not exceed 8 sheets. But the 6mm one, and it only costs $12! It cuts 25 to 30 sheets of POPLAR plywood!!! .

Thanks Andy, I think the answer to my "When should I start buying expensive bits" in our CNC course live chat might not even be a thing now 😂 Cheers, JAYTEE

Thanks, Andy. I'm just starting my CNC journey. This points me to a source for inexpensive bits I can bang on and get good results. Keep the content coming.

Great video as always. Ranks up there with the cheap CNC and laser machines. Your expression after the cherry wood cut was priceless. I’m still not a CNC user, but found this video both interesting and useful. Thanks and keep up the great work.

Great test with impressive results. I will definitely use some of these cheaper bits in my workflow. Thanks for doing a great job at presenting the results.

They start at $18 on Amazon Canada I'm glad you did this it gives me confidence in the coated ones

On the blue bit, that first slow pass wore off the coating from heat and friction of cutting through the powder. If you try it again at 200ipm with a new bit, you should see the coating last longer. But who cuts wood, ply, mdf whatever at 60ipm?

What chip load are you shooting for? Running a bit slow (90ipm) can cause more damage than running it to fast if your RPMs are set incorrectly. "The only difference is this bit is two flute and this one is three flute." That makes a HUGE difference. If you ran both at the same rpms and feed rate then it is not a "side by side" test. Of course the three flute got hot. There was no chips to remove the heat...only dust which just compounds the problem.

Great content thanks.

Very interesting. Spent 6 years working as a machinist before getting my Avid. Working out tool paths with solid wood is actually much more difficult than metal, as the density and grain direction change so much even in the same board. As someone who has a really hard time not using the best tools they can afford, this video has gone a long way in convincing me to use a throw away bit when prototyping a new project. I'd love to see more of this. You may want to think about a small plexi shield though if your trying to break bits! They may not all break as cleanly as that one did.

I have used the HQMaster for a couple of years with excellent results. Always considered them throw away bits but surprised with how long they last

How do we know the discoloration is heat and not pitch esin from the wood?

Great video. Even if I don’t have a CNC (yet-😁)… You’re fun to watch!

Great video, and great advice.

i always buying the """cheap""" bits however i never met with the first bit with 1/8 shank using one flutebits flutes are polished , no eat build up and fairly long lifespan 1-8 bits around 1.50-3 dollar 1/4 bits around 3.50-6 dollar in comparison purchased amana and onsrud bits because """professionals""" told me they hold up longer no, they are not, even using the factory suggested settings on the end posted pictures on amazon and alibaba showing the actual bits, so fairly simple to buy the right one

That router bit is now $12.

i purchased some cheap bits made by Sainsmart / Genmitsu. They were really sharp and actually cut the skin on my finger and drew blood.

Good video, it put the " cheap junk" mith to bed ( not for all bits) but will cause people to examine the bits.

for melamine particle board, what is the best ??

What is the spec on that spindle?

When I watch similar videos..and notice that everyone tightens the bit wrongly. Why do you think that wrench has angles?

I am frankly impressed.

i suppose that running air through the bit would prevent heat damage, might be easier in a milling head instead of a spindle.

Question: The discoloration appears to at the bottom portion of the bit, however, the bit broke near the top. Is the break really due to heat?

Great Video thanka

7:44 You may want to add corrections about up cut vs. down cut -- I believe this is an up cut bit (unless your microscope image is reversed).

First thing they did was went up in price on the cheapest bit..I guess they seen your video. I use nothing but Jenny bits.

What is funny is as soon as I added the Test 3 bit to my cart, the price jumped to $8.

i've had mixed experience with amazon bits from trash to treasure there is everything on Amazon

Thanks for your videos Andy, I have had a 15x15 workbe in my garage since may of 21, I only have the z axis and part of y done. The manual sucks, and have no idea even if I get to the electrical on how bad that will be. Customer service sucks, bulman3d, they haven't contacted me back whatsoever. Should have went with carbide3d.. customer service from everything I saw is awsome.. I will try to finish it, need to, no choice. Any suggestions on forums or something for me to get help on it? Sry so long

I think the first bit is actually HSS, not carbide. Amazon description isn't always right.

Great video.

Suggested test for consideration. How many inexpensive bits would be used to match the longevity of a more expensive bit? Which would be most cost effective?

I would be curious about runout tolerances on the bits. Also curious about longer life testing. Does your spindle raise and lower rpm with feed rate to maintain chip load?

bit number 3 is now $17.50 - 7/26/2023

Great video! Test #3 bit back in stock... AT $17.50 EACH ?! EEAAKK! :P

The bit is always tightened with one hand..that's why it has a wrench angle

Hqmaster makes some amazing bits for the price.

I prefer buying branded bits as they usually come with the setup information needed to run the bit properly, some thinner bits need the correct settings or they will snap, sometimes a specific ramp is needed

Ahora cuestan 15 dólares aproximadamente, parece que con tu vídeo aumentó la demanda y el precio subió 😮

You should test the first bit on a grinder and see if it's really carbide, or maybe they lied and it's just HSS.

andy what cnc are you using in this video

I don't think you can assume that part of the shipping charges don't go to the seller. I think that depends on which shipping method is used. I'd double check that because there's a chance your cheapest bit was your most expensive bit.

I've heard that your not supposed to go any deeper then half the thickness of the bit. That first one would have been 4 times too deep.

Genuinely surprised.

Amazingly whether it be inflation or the manufacture felt they could profit from this videos info. The 3rd bit is now 15 times the price.

I dont know what cutter coating would be blue like that, seems like a nonsense coating to me.

Is there any risk of damage to the machine when the bits break?

The "cheapest 1/4-inch bit" (#3) is now listed at prices ranging from $11.97 ea. to $31.86 on Amazon and all of the vendors checked have it in stock. This bit isn't carbide, though that claim appears in the heading. The product details make clear that it is made of "Durable Tungsten Steel Material." It's also 6mm and not 1/4". There are several vendors selling the same manufacturer's bits, and not one bit is made of carbide; all are tungsten steel. If I had to guess, I'd wager someone sent you the link to bit #3 and provided you a special price to get a positive review with the expectation that others would buy the same bit from vendors selling it at higher prices. Given how I've seen people manipulate prices on items by posting the same item under multiple accounts to make their overpriced goods appear to be "competitively priced," I wouldn't rule that practice out either. For anyone unaware, tungsten steel is a completely different alloy than tungsten carbide. Like consumers, some vendors may not know the difference. However, some vendors (who sometimes fronts for the manufacturers) are fully aware of the difference and use false or misleading claims to sell tungsten steel cutting tools as "carbide" (which it is not). The following article provides an overview of the differences between Tungsten Steel and Tungsten Carbide: www.thomasnet.com/articles/metals-metal-products/tungsten-vs-tungsten-carbide/

for wood the 3 flute bit will not work theres no room for chip evacuation any brand of 3 flutes will perform poorly in wood

How do I subscribe? There's no subscribe button, I do see a join button but this cost money.

Thanks for doing the work so we don't have to!

couldn't find anything close to that price.?

heh...as of Nov 9, 2023 those bits are right at $15 ea

$15 now

Looks like the seller of your third bit knew he would be getting sales, ha! The price is already above $7/bit.

The first bit is not carbide. 100%

now they cost 10x more....