Grasshopper End Mill Giveaway

Free end mills! Sort of, you still have to pay for shipping…

My employer, and a sponsor of the Grasshoppers, goes through end-mills like they’re nothing. We ‘dust’ graphite alignment pads on our product (inkjet print heads) to ±7µm, and when the mills start to deflect an extra 2-3µm we have to ditch them. This results in throwing away hundreds of end mills every year that are in near-perfect condition, but are ‘worn out’ for print-head purposes. Having examined them under a microscope myself it’s nearly impossible to tell that they’ve been used at all.

So, that’s where the giveaway comes in. I have rescued a lot of these from the trash, and would like to send them out to teams who want some nice, free, end mills. I’ve used them to mill titanium and SS with great success. They can be used to mill aluminum, and if you keep the chips clear and the aluminum cool they cut hilariously fast with a wonderful surface finish. Plastics are a little more challenging because of the tight helix angle, but can be milled nicely.

1/4in OD, 3/4in flute length, 5-flute (variable pitch, I think), 2.5in long, 1/4in shank, TiAlN coated.

Product Page.

I am happy to ship these to any one, or any team, interested in getting them to use with their own machines. Let’s limit it to 5x per user for now, but I might change that depending on interest. Send me a PM and I’ll send you my PayPal address asking for $7.25 (USPS flat-rate padded envelope) and for you to put the shipping address in the paypal text field. Send $7.25 as a gift or $7.76 if not a gift. This will help me send the giveaway to those who’ve paid!

1 Like

PM sent!

There’s lots of nice stuff like this that gets tossed in industry every day, but is still perfectly good for a robotics team to use. Good to see it going somewhere useful!

I’ve got a lot of responses so far, awesome!

I’ll ship verything USPS flat rate padded envelope, $7.25, and will take PayPal for shipping costs.

I ordered 45x padded USPS envelopes so I won’t clean out the post office.

PayPal screamed at me to reset my password due to ‘unusual account activity.’


I’m glad to get such a strong response!

I have a little more than 500 of the JHH2500Vs (the one pictured) and about 30 requests so far. I’ll let it run for a few more days and see if I can give away more than 5x per request. Shipping won’t change (yay flat rate).

I also have 16x of these Micro 100 mills for those metric-minded people, and 6x Raptor R61606Cs (dimensions determined by PN). If you’d like any of these let me know, I’ll add one of them to a set of the JHH2500Vs, first-come first-served.

Will you ship to Canada?

Yes. Canada is $25 instead of $7.25 from what I can find.

PM sent

Thanks for your supporting the FRC community.

You’re all welcome! I’ve been seeing a lot of this lately:

And, very surprisingly, a lot of this:

I haven’t ‘run the numbers’ on user responses, but I’ve gotten a bunch of requests from lurkers, which I think is great.

My fitbit and cell phone have been vibrating off my wrist/out of my pocket.

I am really pumped to have a response this strong, and in the off-season no less! 34 paid through paypal and I just responded to maybe a dozen or more new requests.

Did a final count last night: 510x JHH2500Vs, or about $16,580 (new cost) in two shoe boxes on my dresser. :eek:

Thank you again for doing this. You might want to take a quick spin through some of those users w/ 0 posts and make sure they have a team number and an address that’s at least close just in case this made it’s way to Google/Reddit as a “get endmills here” type of thing.

I’m going to stop taking new requests at the end of today so that we can get things shipped by the end of the week. We’re at 59 requests confirmed through PayPal right now!

I’m not going to be accepting any more requests, but those who have submitted requests can still submit PayPal payments through Thursday. I am thinking that we’ll ship Friday or Saturday.

So far we have 72 paid through PayPal!

So, the USPS label making web interface was undergoing maintenance at the end of last week, I was out of town all weekend, and excuses over… I’m getting the first ~20 labels made tonight and they should ship tomorrow. Those in the first group (simply based on date paid) should have their mills in the mail tomorrow!

We’ve wound up with around 80 requests, I should be able to send everyone 6-7 of the 1/4in 5-flute mills. Those who requested raptors should be getting at least 1. The one or two people who requested metric mills will be getting a lot!

I’d love it if people could post up pictures of what they’ve made with these mills, share tips and trips for getting them to run well, and/or (if you’re feeling really generous) stick a Grasshopper logo on your 2019 robot if you use the mills to make a part!

Second batch of 20 are labeled and packed, going to ship out tomorrow.

PayPal email addresses should be getting the USPS shipment notification.


Thanks for doing this James! Very cool of you to spend time shipping these out.

So, I talked with one of the machining center engineers today. Apparently there’s a lot more to the JHH2500Vs than first meets the eye. They are variable helix AND variable flute pitch (the 5 flutes don’t start every 72°), which allows them to cut more smoothly than normal 5-flute mills. Harmonic vibrations do not build up in the part because the frequency of cutting edge impacts is irregular. The blanks are premium carbide from Kennametal. The machines that are used to make them are ~$2M and the operators undergo a 2 year apprenticeship/training program before they can make the mills themselves. Normal selling price is ~$80 each! We get a slight discount because we buy in lots of 100. We toss about 15/week because they get a few microns of drift (which means I’ll have a reasonably regular supply moving forward).

The people who run the machining center are really excited that the end mills are going to good homes and will start sequestering the useful sizes and dropping them off to me every week.

You’re welcome!

Wow. Out of curiosity, do they always run 5 flute or ever anything else?

I’m not sure, I’ll ask tomorrow.

CID makes some interesting mills for a wide variety of materials with between 3 and 8 flutes. I imagine that a particular machine can make most, or all, of their products.

I ran out of packing tape to attach labels :ahh: so the last shipment will go out on Saturday instead of tomorrow.

A big thank you to all those who threw in an extra few bucks! It more than made up for the paypal fees extracted from some payments. The leftovers will buy the team some donuts for our next meeting.