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View Full Version : Need some help and advice, ideas for finishing a detail



Boyan Silyavski
09-12-2014, 10:14 AM
Hi,
i have designed something and just doing some tests. The part is made from 5mm aluminum and has a detail that is 15mm long and 5mm wide/same as material /




Now the problem lies that the protruding part has to go inside into a couple of bearings with ID6mm, meaning i just have to scrape say 0.5mm from corners so it could fit.

Cause of this, i have to make a fixture and turn the part over. Otherwise the part could be machined only one side /actually both sides, but one side is facing, then flip and machine,thats for better precision/.
And be very careful.



I need a simpler way to do it. I have thought and invented some complicated ways :anonymous: , like:

-making it longer , fit on my small lathe and finish,though i have to search and buy new 4 jaw chuck for this. By the way-self centering or not???
-make fixture , screw this inside, then the round fixture on the lathe and so on.





But i am not happy as it must be precise/ better than 0.05mm/ and it would take quite an additional time for all.

I was thinking, if exists something that could help me scrape it simply to shape by hand, that would self guide the 5mm square to 6mm circle. Or something similar. may be it exists already and i just dont know how is called :tickled_pink:




Bellow some pictures so you could understand the problem. It seems stupid to flip machine 100 parts only to scrape 0.5mm.

Any ideas?

http://www.mycncuk.com/attachment.php?attachmentid=14019&stc=1

http://www.mycncuk.com/attachment.php?attachmentid=14020&stc=1

http://www.mycncuk.com/attachment.php?attachmentid=14021&stc=1

http://www.mycncuk.com/attachment.php?attachmentid=14022&stc=1

vargai
09-12-2014, 11:22 AM
my way would be if the Dia 6 mm need to be precise (by hand does not work)

mill the part with the Square 5

make a 4,5 thick nest that should be fit to the lower portion

fix this nest into a fix part of the vice so you already have fixed in the three planes -the center line of the dia 6mm vertical

fix the part in the vice -take a null point in the middle of the diagonals( only at first pc)

make the dia 6 with helix mill

you only need to change the piece carefully and push the green button
(sorry but do not know what means you have)

Boyan Silyavski
09-12-2014, 11:49 AM
I use my friends router, my first build, which is not a mill, but is very precise/0.01mm and still continues to surprise me/

Ok, i get it. I haven't thought of that. So what you say is mill a bed, and then one by one fix them, flip them and mill them. Horizontally yes? Sounds better than lathe and simpler. or you mean the part to be vertical and do it at once? Wouldn't it vibrate like that?

As far as i understand you mean to make all this vertically, so i open the vice

PS:
The 6mm goes into triple bearing, so not that the diameter is so important as the center line of the piece, cause it must rotate dead on its center/2.5mm/ other wise when the bearings are encased, it will try to move them differently and friction will occure

vargai
09-12-2014, 01:29 PM
I use my friends router, my first build, which is not a mill, but is very precise/0.01mm and still continues to surprise me/

Ok, i get it. I haven't thought of that. So what you say is mill a bed, and then one by one fix them, flip them and mill them. Horizontally yes? Sounds better than lathe and simpler. or you mean the part to be vertical and do it at once? Wouldn't it vibrate like that?

As far as i understand you mean to make all this vertically, so i open the vice

Vertically yes but I have not thought to do square 5 and dia6 in 1 step, however it may work -you now as you go down with the mill you have the wider cross section down along the Z path so the 5x5 mm does not have affect to resonate-I think in alu should work especially on your machine:satellite:

PS:
The 6mm goes into triple bearing, so not that the diameter is so important as the center line of the piece, cause it must rotate dead on its center/2.5mm/ other wise when the bearings are encased, it will try to move them differently and friction will occure

Depends on what you have now:

If you do not have material the best seems from 8 mm thick material- horizontally do all with chamfer (upper figure)
flip mill back to 5 mm chamfer ready-problem the r2 radius
http://www.mycncuk.com/attachment.php?attachmentid=14024&stc=1&thumb=1
If corner must sharp you need to do the first step or rough then flip to vertical and do the helix or only remove the radius(lower figure)

Boyan Silyavski
09-12-2014, 01:57 PM
Ok, thanks.

i will try both and see which works better

vargai
09-12-2014, 03:05 PM
At answering I put this into your quote and maybe not noticed:

Vertically yes but I have not thought to do square 5 and dia6 in 1 step, however it may work -you now as you go down with the mill you have the wider cross section down along the Z path so the 5x5 mm does not have affect to resonate-I think in alu should work especially on your machine:satellite:

If you can - try this too -I am wonder if this works- perhaps this would be the fastest with chamfer on the wider edges instead of radiuses (1 step all what I can see in your dwgs)