Grinding Rig to make dovetail ways ...went wrong

[@MrF4eable]

Very interesting idea. This could be a simple solution for making dovetails without expensive tools. Mighty give it a try. Thanks for sharing !!

[@AccidentalScience]

Too bad it didn't worked. It could work, but it would require a lot more: adjustable tilt and alignment, a real rail to carry the piece under work, maybe more power. However, thanks for watching and commenting.

[@robertsteinwandel6658]

This mechanism is actually very similar to the way a radial arm saw works, although your mechanism is for steel of course. The reason it caught your piece of steel and threw it, in the original version, is because your blade was spinning the wrong way. Its counter intuitive but the blade should spin towards you, pushing the piece of metal back towards you. This way if the metal catches and you’re holding it, the metal will not pull your hands towards the blade. Also, when the metal is inserted and the blade spins towards you, it will push the metal away from the blade, attempting to take a slower cut. With the blade spinning away from you, it pulls the metal into the blade as it cuts. A small cut causes the blade to pull the metal towards it, making a deeper cut, which causes the metal to pull deeper into the blade, which causes a vicious cycle ending in your grinder throwing the piece of metal across the room. Just reversing the blade rotation direction would make your setup much safer, and likely easier on the grinder and less likely to cause it to die. The other thing that may be worth considering would be how the wheel deteriorates during the cut. It of course gets smaller as you grind more, however if you removed the bulk of material with 1 grinding wheel and did a second pass with a fresh wheel you could eliminate most of that problem, hopefully to the point where you could hand scrape it to final flatness? Just some thoughts but either way thanks for the amazing content!!

[@AccidentalScience]

> "Its counter intuitive but the blade should spin towards you" Well I was aware of this, but I was afraid that the piece would have been thrown against me so I preferred the other way around, even though with the risk of having the piece seized, as it happened. Also in the case of pushing the piece against the wheel it would be necessary to even push it downward, vanishing the idea of having a reference point. Simply put, this solution was a failure, and wouldn't have worked either way. Idea scrapped. Maybe the second version, with some modifications, could become a useful grinding plane using a larger wheel and a powerful grinder. Thanks for commenting Robert. Cheers.

[@robertsteinwandel6658]

Accidental Science ah yeah thats true, its a shame though because that was a really interesting concept! Have a great day!

[@contemporiser]

I saw it coming 1s after you jammed this bar and 'climb grind' it. Myself, I overloaded one tool in my life, never done it again. Allow them to keep their specified RPM or they will release magic smoke. Gear mechanism in wear is another reason.

[@couldhaveseenit]

Love the idea! Thanks for showing the mistakes :)

[@maruthupandian3728]

i am sorry your angle grinder got shorted out.it was a bit too much of a load for it to handle. nice to see you back safe and healthy.

[@AccidentalScience]

Thank you mate.

[@Demymaker]

I fallimenti fanno parte del gioco ma creano esperienza quindi grazie della condivisione, meglio che vedere video perfettini dove sembra tutto facile. Molto utile la spiegazione sulla smerigliatrice, io qualche volta l' ho riparata ma chiedo umilmente : sarebbe interessante un video su come controllare (elettricamente) i motori di questi aggeggi che abbiamo in casa. Bravissimo in ogni caso, è una realizzazione difficile.

[@rm-uq3ic]

I love the effort i will soon be doing a lathe build also. Using cold steel vs cast iron or cast steel is fine. You may end up with a harmonic vibration issue in the end. A ringing sound from the lathe which may cause chatter.. Cast materials deaden this effect.. However i think if built well enough it is not an issue.. " I have already seen a forged cold steel lathe work well " .. As for the grinder not working my guess is the blade is flexing causing a pinching on the guide that makes it grab the piece.. So keep an eye on that and you have a rig.. Try using a "Ridgid 4.5 metal diamond cutting blade" $13 at home depot.. Or even a spring loaded guide to allow give and reduce binding.. Boing boing lol but with a lot of time it will work. Good luck and cant wait to see the next one

[@rm-uq3ic]

Also work the metal like its on a lathe.. Take of just a tiny pass everytime.. A one pass dovetail like a table saw is too much material..

[@rm-uq3ic]

Also get ready for a bunch of surfacing. Inorder for it to be smooth it will require a very straight surface.. The longer the lathe bed the more straight it must be... Keep up the great work and cant wait to see the next one

[@AccidentalScience]

Hey, thank you for the comment. Yeah I'm afraid of that ringing issue. That is why I've put the ways on a layer of epoxyconcrete (this, among other things, I will show in a summary video.) Greetings.

[@rm-uq3ic]

@@AccidentalScience awesome idea cant wait to see

[@bigjim8088]

Not sure but I believe a cutting disc may work better. Just cut the material where you need the angle instead of grinding to where you need it. You may be able to cut two pieces from one wide piece. The cutting disc cut much better of course. I have tried cutting with a grinding disc and once you get about a inch into the material it just becomes too difficult. Great Work You Are Doing Here!!!

[@AccidentalScience]

Your though is understandable and sounds right. Sadly even a slight misalignment could lead the grinder to jam. To avoid this a different design is required. Furthermore, my idea was to exploit the constant distance between the corner of the "guide" and the edge of the workpiece to gain a decently flat surface. Bad idea, anyway :)

[@athrunzala5337]

Try next time with steel pipes and steel elbows and pipe flanges . . you can set it up and adjust it square without welding . . washing machine motors already have holes to slide back and forth on a pipe ^_-

[@CatNolara]

Hmm, might have been better to build a rig for the bandsaw for this, at least for roughing. Then have a rig with the grinder to finish it off. I think a better way to hold a grinder is the flange where normally the disk guard is mounted.

[@AccidentalScience]

You have a point about making a rig for the bandsaw for roughing.

[@sibalogh]

What material do you use for the slides and do they need to be heat treated?

[@AccidentalScience]

Steel. No.

[@sibalogh]

@@AccidentalScience # You mean flat bar?

[@AccidentalScience]

@@sibalogh yes, they are in steel and not heat treated.

[@athrunzala5337]

I only wanted to mention this after visiting a steel dealer here in my country . . check your steel stock before you buy them . . the dealer was selling a thick rectangular bar with wrong dimensions!! It was 10mm thick on one side and 15mm thick on the other and the bar was 6 meters in length and they don't accept selling it any less than that , ,So imagine 6 meters with wrong dimensions from factory to your door step !! These are weird times

[@AccidentalScience]

So it is a trapezoid ...interesting I didn't even know they exist, but it could come useful in certain situations.

[@athrunzala5337]

@@AccidentalScience No no no , , , it was wrongly forged . . that's why I said be careful when you by the steel. I think the form it was forged in wasn't accurate. I didn't buy , , when I saw this I left. I think this steel was not intended to build machine from but regular construction material. It is not easy to build a lathe but not impossible. My final resolution is that a person should start with a Grinding rig and build it using big pipes and pipe elbows drilled and tapped . . your "cold welding" is also very genius technique which I like . . combined with grinding rig will be the best low price solution for achieving precision. There are aluminum oxide CUP grinding wheels and also cheap chinese diamond cup grinding wheels which can do the work faster than abrasive disck on angle grinders. Washing machine motor I think is better at grinding

[@AccidentalScience]

@@athrunzala5337 Ahh gotcha. Unbelivable! Where I live that is virtually impossible to happen. The material would be rejected by the stockist well before it reaches the final dealers. But I understand that could happen elsewhere. P.s. Sorry for the delay but YT held your comment because it (mistakenly) detected as spam, so I had to manually approve your comment.

[@athrunzala5337]

@@AccidentalScience You are very lucky to have quality control in your country. I like the fact that you are trying very hard to build a lathe without relying too much on machine shops because to a lot of people this can make the price go up very quickly and might intimidate them to give up. Good luck and let's see a happy ending to this project. I'll keep watching.

[@ihateemael]

the steel is growing with the heat and jamming . . which causes it to get hotter etc.

[@AccidentalScience]

yep

[@markfryer9880]

Buy yourself the same model grinder again and keep the dead grinder for spares.

[@AccidentalScience]

Good idea.

[@misteragb7558]

Why not just linear rails?

[@AccidentalScience]

Do you mean using linear rails in place of making these ways?

[@milithemuffin4534]

It is possibile to use linear rails, but they would have to be quite beefy and spaced far apart. Rolling element guides are awesome for cnc routers because of their preload and low friction but in a lathe rigidity and damping are usually more importnat than few microns of backlash since cutting force is always acting one direction.

[@AccidentalScience]

@@milithemuffin4534 exactly.

[@MadHatter123456]

Seriously considering making dovetails out of cold-rolled steel? First mistake.

[@AccidentalScience]

LOL love your comment. But rethinking on it, what's wrong with cold rolled steel?

[@MadHatter123456]

@@AccidentalScience pretty much everything. There's a few good reasons why almost every machine tool is made out cast iron...

[@MadHatter123456]

@@AccidentalScience pretty much everything. There's a few good reasons why almost every machine tool is made out cast iron... Edit: On a second thought. If all the rest is made out of cold-rolled steel then the dovetails gibs won't make it any worse.

[@3600alee]

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