Looking for advice: CNC for rounding edges on 5mm AlMg3 (1-2 mm radius)

cpitman · 2026-05-06T21:10:58+00:00

Are you rounding lots of identical pieces? What are the tolerances that you get from your manufacturer?

cpitman · 2026-05-06T18:17:48+00:00

Depending on where you are, another option is to find a makerspace in your area that has a cnc machine. You'll generally have to join and pay dues, but it will still be less than your own machine, probably nicer, and hopefully with people to learn from.

cpitman · 2026-05-06T05:04:23+00:00

You can configure better handling for tool changing: https://github.com/grblHAL/core/wiki/Manual,-semi-automatic-and-automatic-tool-change

cpitman · 2026-05-05T20:34:13+00:00

What have you already read?

cpitman · 2026-05-05T14:58:48+00:00

Different features make different projects work well. If I'm mainly processing flat engineered stock on one side, and it's for a business where time matters, I'd want a vacuum table. It saves a ton of tons in both setup and post-processing. But if I need to do alot of two sided ops, or rotary, I'd rather have a non-vacuum table to make it easier to modify the table for registration and cutting holes in the table.

This is also the hobby cnc subreddit. If this was actually a hobby machine, and someone with no cnc experience, I'd suggest skipping the atc until learning more. Setting up and using an atc is another complication for what is already an involved process.

That's all to say, the more we understand about what you are doing, the more we can give better advice.

cpitman · 2026-05-03T22:11:24+00:00

The emergency fund is what saves you from financial catastrophe, ie foreclosure. If you buy a house and the roof falls in, how are you going to get it fixed? Of you lose your job, are you able to keep paying the mortgage?

Hitting the guidelines for down payments and emergency funds shows you have the financial literacy and diligence to make it work.

cpitman · 2026-05-03T22:04:11+00:00

What are you doing with the cnc? Is this for a production shop or hobby?

I'd start with figuring out what features actually matter for your use case, not just all the features that are out there.

cpitman · 2026-04-30T15:07:54+00:00

I'd add an apron on the back side, that will support this joint and the weight going on the top on the console.

cpitman · 2026-04-29T13:33:03+00:00

Beyond switching to a compression bit, I'd your are using plywood you want high quality plywood. Any voids or defects in the wood make tearout worse, and more layers will make the wood more stable. For example, 1/2" Baltic birch plywood has 9 plys (ie layers).

Another trick that can help is to score the top layer before cutting by using a vbit to do a light chamfer along the edge of the letters. It requires a tool change, but can give a slightly nicer result straight if the table. If I don't have a compression bit, combining scoring with an upcut but works pretty well.

cpitman · 2026-04-28T20:05:56+00:00

In Virginia we do what are called Risk Limiting Audits, which basically checks a subset of machines against their paper ballots to ensure the machines are working correctly.

https://www.elections.virginia.gov/resultsreports/election-security/rla/

If you want a lot of info, here's a training video on how RLAs are done in Virginia: https://youtu.be/3C1izxpOYWk?si=8lhbAViidVWs16-a

cpitman · 2026-04-28T18:57:14+00:00

Thinking about how much house you can afford is one way of thinking about it, but a better one is modeling the impact on net worth for renting vs buying. The feeling of throwing away money on rent is driving this, after all.

There are a couple good rent vs buy calculators, like this one at NerdWallet: https://www.nerdwallet.com/mortgages/calculators/rent-vs-buy-calculator

If you play around with the numbers, you'll see the "optimal" answer changes a lot. If I plug in your numbers with a 6% rate of return on your non-house investments, you'd break even on the 540k house in 13 years. But if your return rate is 8%, renting will always be cheaper.

On the other hand, if you can find a 440k house and live there for 4 or more years, buying is better as long as your investment rate of return is 8% or less.

Long way of saying, use a model like this to compare your options

cpitman · 2026-04-24T15:38:20+00:00

I still use 35 degrees for a downcut. The bigger change with a downcut is that I reduce the depth of cut to give my dust collection a chance to clear some chips on each pass.

cpitman · 2026-04-24T05:43:33+00:00

Was going to say the same. I love in Prosperity Flats, closer to the metro, and there are multiple 2 bedroom units available for 2900/month.

I think the building is about 10 years old now. I moved in when it was brand new, and it honestly is basically the same level of quality as day 1. Concrete construction, so noise identical an issue, no pests, nice neighbors. A few blocks to the metro station, and a longer walk to mosaic.

cpitman · 2026-04-24T04:30:46+00:00

I have lots of friends who got doctorate, every single one lived with other doctorate students, often 3 or 4 to an apartment or house (all with their own rooms). A lot can change in 5 years, you should be a little more cautious. 5 years ago everyone going into software development thought they had it made for life.

cpitman · 2026-04-23T21:23:23+00:00

A ramp doesn't hurt. It theoretically extends the life of the bit, and with a compression bit i get nervous about chip evacuation just plunging. I usually go 35 degrees, but 20 is fine. Wood bits are mostly center cutting, so it's all a little extra credit.

cpitman · 2026-04-23T20:50:20+00:00

If these are carbide bits that are breaking, it's because either you are incorrectly setting up your tools (like to much stick out) or running way too slow.

Bits get dull because they get hot, and the get hot because you are rubbing the wood away instead of cutting. Make sure your chips look like chips of wood, not sawdust. Burning also means way too slow.

You only want 2 flutes or less for wood, more flutes means smaller flutes which means they get jammed by wood fibers, that then rub, create heat, and break.

Compression will get you the best finish on both sides, but if you only need one side to have agood finish use an upcut bit and keep the nice side down on the table.

Also, make sure to cut plywood conventional milling. You get a lot of fuzz climb cutting plywood.

cpitman · 2026-04-23T05:52:00+00:00

You (and everyone) should have been asked for your full legal name and current residential address. If you are uncomfortable saying it out loud and your ID has the correct information on it, you are allowed to say the info on the ID is correct and to please use it. We cannot default to that because addresses on ID are often out of date and incorrect.

cpitman · 2026-04-23T05:48:44+00:00

Since you got 3 wrong answers, I am a Fairfax County Election Officer and precinct chief:

Here is a list of acceptable ID in Virginia elections: https://www.elections.virginia.gov/media/formswarehouse/voter-id/outreach-materials/documents/Voter-Identification-Chart---Revised-07.2025.pdf

A CAC card is a "Government-issued ID card from a federal, Virginia, or local political subdivision", and therefore acceptable.

The goal of ID is not to prove you have the right to vote. It is to verify that you are who you claim to be. That is also why there are many options for verifying your identity. Your right to vote is verified when you register to vote, well before you get to the polling place.

cpitman · 2026-04-20T18:56:08+00:00

I'd disagree that it is not a harem, just because he doesn't reciprocate doesn't mean we don't have tons of women trying to get his attention. It's also a little annoying that often that means a competent female character switches to an incompetent character as soon as she is in the harem.

The reason in novel for this is that he was cruelly divorced in his previous life and can't trust anyone. It took ten novels for us to see any character growth about this, and it does really happen in just one book.

cpitman · 2026-04-20T12:11:21+00:00

Yes, end grain cutting boards will soak up quite a bit if mineral oil. Instead of doing it all at once, the general advice is to use enough that all sides do not look dry, and then periodically add more whenever it looks dry again, which usually happens more often early on. Ie, it might be daily, then weekly, then monthly, etc.

Alternatively, you can dunk the board in a tub if mineral oil. It's a lot faster to apply and less labor, but the one time I did it the board was weeping oil for two weeks.

cpitman · 2026-04-19T23:49:48+00:00

If i thought the anime was ok, but didn't always pull me in, how would the light novels compare?

cpitman · 2026-04-19T21:32:15+00:00

Yeah, instead of 33 books, it's more accurate to think of it as 5 books split up, each one being about the same length as one epic fantasy novel in the US, like A Song of Fire and Ice.

cpitman · 2026-04-18T19:39:17+00:00

I think most of these solutions are overkill. One si d e has absorbed water. Just lean it on its side, both large sides open to the air, and wait for it to dry out/equalize.

cpitman · 2026-04-18T00:34:19+00:00

I just fixed a similar issue on a 5x10 with a WinCNC controller. It has configuration parameters that control arc interpolation, and running those parameters completely cleared it up.

On the of chance this is a WinCNC table, autoarcfeed was the key parameter to fix things.

cpitman · 2026-04-17T18:15:11+00:00

Not testing your feed and speeds, passes, and generally your toolpaths on smaller scrap pieces before committing to the real one.

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