[fragger6662000]

I thought i would start a thread on my conversion of the SPG 2217 20lv machine.

This is my second machine that i am converting as i have already CNC'd an X1, but his will be the first with Ball Screws.

i used SPG as they were the cheapest and most convenient and £800 delivered was a good deal. i did considered an X3 but the volume and quality is far inferior in my opinion and was a lot more expensive.

I went for the MT2 machine as i have tooling in that size and was the one available.

here is the link to the machines supplier SPG TOOLS - Lathes, Mills and Tools for Model Engineers

heres the un-boxed machine


I always new that the clearances on this machine was tight but the X axis is the worst. I am planning on using 16mm dia 5mm pitch screws on the X and Y but 25mm x 5mm on the Z.

Here the table clearance issue.



The standard screws are 16mm and the clearance above is 2.5mm and 5mm bellow so to squeeze the ball nut i am going to mill a slot in the saddle and mount the nut on the out side of the saddle. As per the photo's.



I will also have to modify the ball nut by grinding the top flush to the rest of the nut.

Z axis should be a little more straight forwards as there appears to be no clearance issues.



And here is the current cad progress.



CNC wise i am going to go for the G540 with 3 23 steppers and 1 34 for the Z. The 381ozin on the X and Y should be more than enough and 900 ozin for the Z. Longrat is running the bigger brother to this machine with just over 420ozin on the x and Y.

And before any one say anything about the scheme i got a very good deal on sky hooks and that how i am going to mount the motors.

I have also included the pdf of the screw order. The 600mm one is for my lathe so ignore.

[LongRat]

My advice, make a 1-piece nut mount for the Z rather than the 2-piece I did for the BF30. That's the weakest part of my conversion.
CAD models looking nice. The BF20 is really getting popular these days isn't it?

[fragger6662000]

Here are the planned schemes for the Z and X motor mounts.





i am planning on using 25mm oldhams on the x and y with 34mm on the Z.

[fragger6662000]

I have cut the first part yesterday and it was the x axis motor plate. i started with this part as i was also going to use it for the y and base the y base mounting on the same design.

Overall it came out well and only took just over and hour with a 6mm cutter.

[fragger6662000]

Machine up one of the end plates now

[fragger6662000]

Machined the second table plate and the second nema 23 motor mount.

Ordered the ball screws and motors and controller, progress with the x1 is slow so i am really looking forward too the completion of this machine.

I also programmed the Column cap, Y mounting plate and Z ball carrier that i will try and cut tomorrow.

[fragger6662000]

I was wondering if any one had used a cutting disc in a dremel type tool on there mill to cut the flange of the ballscrews instead of taking it to a bench grinder. The peroxon that i have is only 100w but i think 20-40um cut will nibble through the flange quicker than grinding.

[mrcodewiz]

I was wondering if any one had used a cutting disc in a dremel type tool on there mill to cut the flange of the ballscrews instead of taking it to a bench grinder. The peroxon that i have is only 100w but i think 20-40um cut will nibble through the flange quicker than grinding.

My guess is that you won't have much luck but let us know. When I have used those dremel cutoff wheels in the past, they have tended to grind down pretty quickly when cutting off something as soft as a bolt.

[robcap]

I was wondering if any one had used a cutting disc in a dremel type tool on there mill to cut the flange of the ballscrews instead of taking it to a bench grinder. The peroxon that i have is only 100w but i think 20-40um cut will nibble through the flange quicker than grinding.

I used a Dremel with a 1 1/2" fiberglass reinforced cut off wheel to cut off 3 large chunks, then I used the bench grinder to clean it up.
Take your time, you don't want to overheat the ballnut.

Nice job on the conversion!

[fragger6662000]

I was going to go down the fiberglass reinforced grinding disc route.

Glade to hear that i am not the first to try it.

Thanks for your comments

[fragger6662000]

Here are the 3 complete motor plate.

[fragger6662000]

Had a delivery!

[fragger6662000]

i mounted the dremmel on the mill and used a reinforced cutting disc to remove the flange from the ball nut to create the clearance that i needed.

the cut was so good that i did not have to regrind the surface just dress the sharp edges.

[fragger6662000]

just been dry fitting the X axis to the saddle and found what i already knew the a 5mm pocket is have to be machined into the saddle to accommodate the ball screw. So it is of to the X1 to tickle the material off.

[fragger6662000]

Here the latest progress, went retro with the 80's electronics. I also used some cable sleeving to neaten up the stepper wiring.





The cable tie is just a temporary measure.

All test and seams to be working just know need to couple to the screws.

Why does electronics take 5 time longer than you expect?

[mrcodewiz]

5 times? I'm still working on my enclosure box and I started last year.

I dig the retro enclosure - especially the fish net stockings on the steppers.

[fragger6662000]

this has only taken me 8-10 hours and 6 of them was cutting the hole in the panel and covering the front. this setup is a lot easier than the previous on with individual drivers, fans, transformers, caps, bridge rectifiers, breakout boards etc etc.

[fragger6662000]

Not really Part of the CNC conversion but i got this 4" Vertex table for £99 at the model engineering show at Alexander Palace Yesterday. It even had a test certificate, there was a knock off copy for £85 and there were other stands with them at £105 which was also factory soiled and £120 which also looked beaten up. Overall the show was quite good but there was not a lot of private models / display items.



I also got clamping set for £28.95 which was £8 cheaper than normal and £20 cheaper than other sellers. And i also got a pair of MT2 collets for less than £10.

[fragger6662000]

I also plan to CNC the rotary table!

[fragger6662000]

Further progress is that I have had the X axis running inverted and that seams to run fine.





Secondly i have started on the Y axis and have machined a ball screw mount and i am planning on running with the standard nut arrange where the nut carrier is secured with two screws.

Here is a picture of the modification of the ball screw but to allow it to fit in the pocket in the base. Lots of sparks and really good finish

Some action shots





The X1 is hanging on at the moment but cannot wait to stretch this machine legs out.