Kress mount Europe

Assembly questions and answers for the Shapeoko 3 CNC Mill
Alie
Posts: 27
Joined: Wed Apr 01, 2015 12:15 pm

Re: Kress mount Europe

Post by Alie » Mon Oct 05, 2015 6:19 am

I have an 8 mm flat end bit that i used with my dewalt d26200 while waiting for the kress, i am waiting to get some more in smaller diameters (4 mm to 6 mm) from eBay.
All of them are solid carbide bits.
In the meantime I made an "adapter" out of plywood to mount my kress into the existing spindle mount (basically it's only a ring with outer diameter 69 mm and inner diameter 43mm) which is working very well, the only problem is the kress gets pretty hot not having contact with metal to dissipate the heat.

AnonymousPerson
Posts: 758
Joined: Sun Apr 26, 2015 1:16 pm
Location: 3753 Cruithne

Re: Kress mount Europe

Post by AnonymousPerson » Wed Oct 07, 2015 4:39 pm

If anyone needs a model for a basic Kress collet spanner, this one's functional:
Fusion 360 screenshot.png
Fusion 360 screenshot.png (87.24 KiB) Viewed 1955 times
Kress collet spanner.stl
(44.03 KiB) Downloaded 132 times

Fusion 360 link, for anyone wanting it in other formats: http://a360.co/1RtTaML
Licensed as: Creative Commons BY-SA.

CNC-d it out of 5mm thick aluminium, and it works ok. :)
Kress collet spanner.jpg
Kress collet spanner.jpg (213.73 KiB) Viewed 1947 times
Shapeoko 3 #516

AnonymousPerson
Posts: 758
Joined: Sun Apr 26, 2015 1:16 pm
Location: 3753 Cruithne

Re: Kress mount Europe

Post by AnonymousPerson » Sat Oct 10, 2015 5:14 pm

This is the 3D printed Kress mount I've been using for about a week or so, and am happy with it:
Raised height Kress mount 2.jpg
Raised height Kress mount 2.jpg (132.43 KiB) Viewed 1928 times
Raised height Kress mount 2-1b.jpg
Raised height Kress mount 2-1b.jpg (260.02 KiB) Viewed 1928 times
Raised height Kress mount 2-2b.jpg
Raised height Kress mount 2-2b.jpg (268.82 KiB) Viewed 1928 times
It's fairly tall on purpose, to raise the Kress. My end mills are fairly long (to reach deep into things), so need the extra height.

Here's the Fusion 360 model if anyone wants it: http://a360.co/1jldYKr
License: Creative Commons BY-SA
Shapeoko 3 #516

AnonymousPerson
Posts: 758
Joined: Sun Apr 26, 2015 1:16 pm
Location: 3753 Cruithne

Re: Kress mount Europe

Post by AnonymousPerson » Sat Oct 10, 2015 5:21 pm

Same model, in various formats in case it's useful. All compressed with 7-zip.
Raised height Kress mount 2-stl.7z
(296.71 KiB) Downloaded 291 times
STL format
Raised height Kress mount 2-stp.7z
(197.62 KiB) Downloaded 101 times
STP format
Raised height Kress mount 2-iges.7z
(204.82 KiB) Downloaded 98 times
IGES format
Shapeoko 3 #516

AnonymousPerson
Posts: 758
Joined: Sun Apr 26, 2015 1:16 pm
Location: 3753 Cruithne

Re: Kress mount Europe

Post by AnonymousPerson » Sat Oct 10, 2015 5:24 pm

The aluminium blocks turned up for making into mounts. Haven't yet tried cutting them, as it's not urgent for me and no-one else has really seemed super keen. ;)

Still need to figure out how to drill the mount holes on the back of them accurately too. If they're not placed perfectly horizontal with each other, it'll mount the Kress on an slight angle and be pretty useless. :roll:
Shapeoko 3 #516

AnonymousPerson
Posts: 758
Joined: Sun Apr 26, 2015 1:16 pm
Location: 3753 Cruithne

Re: Kress mount Europe

Post by AnonymousPerson » Thu Oct 15, 2015 3:53 pm

Still plugging away at this. Tested cutting the 1inch thick aluminium 6082 T651 today. Mostly worked. :lol:

Took about an hour (mostly running between 2-3 speed setting), with the HSS drill bit making very unhappy sounds near the end (from about 75% of the way through). Notice the really discoloured end mill:
First attempt at cutting 1inch aluminium 4-1.jpg
First attempt at cutting 1inch aluminium 4-1.jpg (400.54 KiB) Viewed 1896 times
The process generated enough heat to soften the plastic mount holding the Kress, so I had to keep it steady by hand at the end. After finishing, the cut part was too hot to touch. :o

Ran it under a tap, and steam came off! :shock:

Due to a brain-o on my part with roughing-vs-finishing settings in Fusion 360, the cut hole is too large by 1.5mm. So this part is useless for anything except practise. :evil:

Ah well, was kind of expecting that anyway. Have ordered new end mills. Suspecting this one was blunt anyway, from recent abuse testing out other things. ;)
Shapeoko 3 #516

Alie
Posts: 27
Joined: Wed Apr 01, 2015 12:15 pm

Re: Kress mount Europe

Post by Alie » Fri Oct 16, 2015 5:47 am

How many flutes does that milling bit have? It seems 4 to me, i think they are too much for milling aluminium...more flutes=more speed to have the optimal chipload.
What speeds did you use? I also tried last weekend with a piece of 6082 aluminium and ruined a bit (5 mm 2 flutes flat end mill) fiddling with the settings, I think I used too high rpm because there was pieces of aluminium stuck to the flutes...this weekend I will try with a 8mm bit and the dewalt router to see how it goes.
I think that the dewalt blowing air toward the piece is helping with the cooling to some degree.

Inviato dal mio D5503 utilizzando Tapatalk

AnonymousPerson
Posts: 758
Joined: Sun Apr 26, 2015 1:16 pm
Location: 3753 Cruithne

Re: Kress mount Europe

Post by AnonymousPerson » Fri Oct 16, 2015 5:50 pm

Yeah, that was using a 4 flute 10mm HSS end mill, 300mm/min speed, and 0.1mm depth per cut. Definitely far from optimal. ;)

Trying to go any higher than 300mm/min at that depth just wasn't feasible. The 3d printed Kress mount (10% infill) definitely wasn't strong enough. Tonnes of shaking, very very unhappy sounding.

Thinking about it more, it might have been feasible to go shallower per pass (eg 0.05mm), but much faster so the heat could dissipate. Could be worth a shot.

That being said, I have some 20mm thick aluminium plate too, and a single flute 5mm end mill long enough to get through it (but not long enough for inch thick stuff). Might try that next.

If I can get a decent mount made from the 20mm stuff, it should improve the rigidity of things a lot. That may allow cutting inch thick stuff at speeds more appropriate to a 4 flute 10mm end mill. :)
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Alie
Posts: 27
Joined: Wed Apr 01, 2015 12:15 pm

Re: Kress mount Europe

Post by Alie » Mon Oct 19, 2015 6:30 am

With the dewalt I used 1000 mm/min with 1 mm stepdown with a 8mm 2 flute carbide flat end milling bit to cut the electronics shroud of the shapeoko to accomodate an 80mm fan to better cool the motor drivers and there were no problems (i think that's 6061 alu).
I tried milling the 20 mm piece i ruined last week to do some testing and it was all going well until i had the disconnection problem some already had; until then with 1000 mm/min 0,5 mm stepdown the machining was going flawlessly, enven the finish was pretty good for a 2 flute bit!
I hope i can solve that problem asap so i can go on making the mount.
You could try making a plywood or mdf ring with inside diameter 43mm and outside diameter 69mm so you can put it inside the existing mount with the kess attached and not worrying of it melting (and being much stronger than 3d printed plastic).
PS: i think you would be good with a 20mm thick mount as every seller for the 43mm mounts uses that thickness, i think the few more millimeters upgrading to an inch think aren't adding that much strength (the flex in the z axis plate is a bigger problem).

AnonymousPerson
Posts: 758
Joined: Sun Apr 26, 2015 1:16 pm
Location: 3753 Cruithne

Re: Kress mount Europe

Post by AnonymousPerson » Mon Oct 19, 2015 7:40 am

Does your insert just keep in place due to the clamping action between the existing mount and the spindle?

Hmmm, would you be ok to take a photo of yours, to better illustrate? :)

I'm kind of getting sick of the unreliability of the 3d printed mounts when really pushing them. They're ok with a lot of simpler things, but when the forces get too high... not so good. :evil:
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