I got linear shafts which are intended to be used as guides for 3d printers (64 HRC 12mm) but need to be trimmed to the correct size. How would I go about this? Which tools are required?
Is a normal angle grinder enough to cut hardened steel, and do I mess up the shape of the steel due to introducing heat?
An angle grinder will do it. At the precision level required in a 3d printer it's OK to use the grinder. Just be careful not to bend it and use soft jaws to hold it in a vise.
wrap a wet cloth near the cut to wick heat away, on both sides of the cut. A thin abrasive disc in an angle-grinder is exactly the tool. Stop often to let it cool.
Use an abrasive wheel; in particular use the thinnest cut off wheel possible for your angle grinder. To minimize heat buildup with abrasives, simply rock the wheel back and forth a bit and use light pressure. More sparks coming out of the cut equal less heat staying in the part. After cutting, let the part air cool.
Always wear proper eye and face protection when using abrasive wheels, other important PPE may include dust masks, hearing protection and proper clothing. Be sure your cut off wheels are properly RPM rated for your grinder.
This is the most correct answer
Huh, that was NOT what I expected from the title.
I use trimmers
Also, cover the bit of the rail you want to keep to avoid surface finish damage from hot sparks. Tape is fine, aluminium foil is fine.
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Good point. Sparks actually do damage...
I was thinking it could be done in the shower with a razor and conditioner to soften the "fibers".
Angle grinder with a cut off wheel. You'll lose hardness right on the end you cut, which can be reduced a bit by wrapping it in a wet rag, this will also reduce the chance of warping if it's a smaller diameter. But even without it will probably not be enough to be noticeable. The rails are meant to be travelled the most in the middle. The ends are typically clamped in a holder and the hardness does not matter.
Also be careful not to scratch it when you clamp it in the vice to cut.
I used to know of a shop with a waterjet that would take small jobs on the weekends. If you could find something like that… Or wire EDM. Less heat damage. But 12mm? I’d use the grinder with the excellent tips already mentioned.
Curious - is it a 3d printing process with abrasive materials involved? Like SLS? Those shafts won’t see much force. HRC50 I think you could use a cold saw.
OPs mom helps me with mine.
One last addition? Don’t forget to deburr! Trying to slide a bearing or bushing onto the home cut end could be problematic. Once the cut is finished, use the grinder to put a SMALL chamfer on the end so you guarantee you don’t have any burrs sticking out past the original outer profile.
Well done! No circumcision is complete until the deburring is done.
I had the same initial thought 😂
Grinding is the only way other than waterjet cutting at a local shop. An angle grinder is going to move around a bit at the start. An abrasive wheel in a cutoff saw would be the best (making sure the wheel is rated for the saw RPM and wear a full face mask). The shaft will spin if not secured. A spray bottle of water and going with very slow cuts would be the best.
Think about baseball, or your grandmother.
> Or wire EDM.
As an EDM operator... thanks for the laugh.
It isn't cost effective unless you require precision length. It would be about $100+ to cut something like that.
Use an air powered cut off wheel and run water over the cut. Cheap, easy, just make sure to oil the tool before and after.
Totally agree. But if the shafts were 40mm, it would be money very well spent.
No it wouldn't.. as the cost of EDM would also go up.
You are ignoring a very important word.
precision
That is what an EDM does.
The angle grinder is fine. Get a milk jug, fill it full of water, and poke a hole at the bottom to get a little stream coming out. Hold the rod in the stream and cut it wet, or at least cut it for a second, then quench a second, and repeat. The grinder will cut it just fine, but it'll get hot, and you want to avoid that.
Then I stand corrected.
Edit: I’ve had parts made by wire EDM (cutting dies), and had very high aspect ratio holes (50:1 or so) drilled by EDM. But never sinker, which is a truly fascinating process. You do any of that?
I do wire EDM. As well as ProtoTrak milling. (ProtoTrak is kinda a half way between manual mill and CNC)
Sinker EDM functions on the same principle. And EDM drilling is just sinker with a round electrode. But allows for a smaller machine.
(all measurements are in imperial, as it is what I am use to)
Punch and dies are the bread and butter of EDM because of the level of precision. Normal machining, you deal with +/- .005.. good manual mill guys can hold .001. With an EDM you can hold .0001.
When I was taught, we made Punch and Die sets out of the same block using a very small wire .002 wire. One cut, and you have both parts ready to roll. But a pain in the ass to actually set up. As everything has to be perfectly straight.. as in less then a tenth of a thousands run out over 6 inches.
I would consider EDM way above any DIY work. It is akin to the posts you see on here where someone DIY a part using a half million dollar CNC mill with thousands of dollars in tooling. Nothing that I would expect from an at home DIY.
On average, I spend at least 30 minutes doing setup (mounting the part and stops on the machine table), and then another 30 minutes writing the program. So it feels like a big waste of time when the job is 1 part, and only takes 10 minutes to cut. But the customer pays for all that time.
Use a table or miter saw and just send it
(Don't do this)
Thanks for the thoughtful response. My original comment was really suggesting waterjet. Probably should have left the EDM out. I get the sense you feel your trade was undervalued - and that was not my intention at all. I have the highest respect.
An angle grindr can fix most problems in life tbh
Jumping on to the top comment to add: make sure you wear a face shield AND safety glasses. And be very careful you don’t skew the blade to one side or the other. Thin cutoff wheels will shatter.
> I get the sense you feel your trade was undervalued
Not at all. It is more of a "right tool for the right job".. or as they say... application is everything. No sense using a highly precise cutting method when a saw will do.
My issues are more with this DIY sub then anything. I feel that many don't like a professional giving advice, or commenting on what is inaccurate.. despite many posts using professional equipment and then claiming it is DIY.
I wouldn't post what I do at work here, because it isn't fit for this sub. I am a professional using specialized tools and equipment. Despite me "doing it myself". But if I did an at home fix, where I didn't use my $100k+ machinery and tools, that would be fitting for this sub. And from what I have noticed, people want to make themselves look professional despite not being.. as if saying "yeah, I'm not a pro" is a bad thing.
Edit: I can honestly say our interaction.. has been the best I have had on this sub. I normally get a very negative reaction / attitude because I know what I am doing when it comes to metal work. I suck at wood, and am not afraid to admit it. I hope you have a wonderful weekend.
I cut mine with a shitty little 6" hacksaw and a miter guide I printed. Realized later with my move to Igus bushings that I didn't need expensive hardened steel to begin with. [still good idea use hardened if running steel ball bearings]
But ... you make, you live, you learn.
Have a great weekend. I’ll be trying to make a 6x8 array of very small holes in glass using hydrofluoric acid, 600 grit garnet, and gentle drilling. So…much cursing, probable lung damage, and quite possibly my garage declared uninhabitable. Hope you have something similarly fun planned!
Oh my...
Stay safe, be careful.. I have used hydrochloric acid before. Lots of ventilation. Be careful with metals downwind.
Your comments have been appreciated. While EDM surely isn't applicable to my use case, I still pulled up google yesterday and learned something new about a topic I didn't even know existed :)
What a nice offer. Thank you, but round turn shipping from the eu would cost much ore than the alternative.
:)
I agree, good point (PS, I have scars)
A vise is handy to hold the work, but make sure you have some wood or something in there to protect the shaft. The jaws will definitely fuck up your shaft if it's not adequately protected.
Also, if you want a bit of exercise, you could probably make it happen with a hacksaw.
coherent-rambling t1_isa2o23 wrote
Yes and yes. Any kind of abrasive cutting like an angle grinder will go through hardened steel. But the areas closest to the cut will lose some of their hardness and may be slightly distorted. Just take it slow with modest pressure and don't expect a precision cut end.