View Full Version : X2 Timing Belt drive (cheap, of course!)


blades
03-24-2008, 07:56 PM
El Cheapo strikes again! This time around it's an inexpensive belt drive. I've got about $40 into the 2 pulleys & 2 belts (one spare).

The beauty of this project is it's simplicity. The 18 tooth spindle pulley has a hub diameter and overall length nearly identical to that of the upper spindle spacer on the X2. The only modification required was a 30mm bore with a 5mm keyway. Thanks to Toyota for being the unoffical sponsor of this modification. The mill work is a bit rough on the aluminum. Most of it was done by hand & on a small drill press. I will probably end up making a nicer piece with better dimensional accuracy than this one. But for now, it serves the purpose and seems to work quite well. Also forthcoming is some sort of integrated spindle lock, since I obviously lost it with this mod.

http://i142.photobucket.com/albums/r89/autocadder/beltdrive1.jpg

http://i142.photobucket.com/albums/r89/autocadder/beltdrive2.jpg

http://i142.photobucket.com/albums/r89/autocadder/beltdrive3.jpg

Regnar
03-24-2008, 08:04 PM
Nice Job. Especially for 40 bucks. Now we need a Video!

mrcodewiz
03-24-2008, 08:51 PM
Nice Work! That is a nice simple design. One big difference between yours and others I have seen is the toothed pulleys instead of the V pulleys. Yours won't allow for any slipping - you may want to put some sort of cover over the exposed belt - No idea what might happen if you lock up the spindle. Wouldn't want to see it break and fly off at you.

Oldboy
03-24-2008, 09:20 PM
Very nice!
blades could you tell us the P/N & where to get the Parts?
What RPM you get out of that set up?

pzzamakr1980
03-24-2008, 09:44 PM
I purchased my belts and pulleys from quality transmission components. They have ads all over cnczone. SPDI is also great, and they have a better selection.

kanton
03-25-2008, 01:24 AM
Part numbers and addresses would be helpful.

LeeWay
03-25-2008, 05:16 AM
This looks great. I too am looking for the pulleys. I already have the Steele belt conversion and have add a large 2HP treadmill motor that I run on 220. It runs about 3800 rpm on the Steele drive in high speed pulley. This motor has loads more torque than the OEM mill motor and I see belt slippage where the original motor would have just stalled.
I looked on SDP and didn't locate anything with a 30 mm bore. I do have a mini lathe, so making the bore a little large will be easy enough.
I have never broached a keyway, but I have thinned down key stock after I moded a pulley bore or I have also installed two set screws into the slot.

I guess I need to learn to broach.

What size bore did you start with?
Thanks.

digits
03-25-2008, 05:27 AM
I have never broached a keyway, but I have thinned down key stock after I moded a pulley bore or I have also installed two set screws into the slot.

I guess I need to learn to broach.

What size bore did you start with?
Thanks.

Broaching is obviously nice and neat, but I have made pretty decent pulley keyways by simply plunge cutting with an endmill and then squaring up with a hand file. As this is just a spindle pulley, you don't have to worry about backlash, so a little keyway slop doesn't really matter IMHO.

BTW, lovely conversion Blades - using that box section is a great idea!

blades
03-25-2008, 09:41 AM
Hey guys, thanks for the comments! For those so inclined to copy this project, here's the P/N's from http://www.sdp-si.com/

12 tooth motor pulley (.500" bore) A 6A 4-12DF05016
18 tooth spindle pulley (.625" bore) A 6A 4-18DF05020
33 tooth belt A 6R 4-033050

This pulley combo gives a 1.5:1 reduction, with a theoretical no-load spindle speed of 4000 RPM. You also lose your lower-end torque with this setup, but this is ok for my intended use of the machine.

Please note that the 12 tooth pulley P/N I have given here is NOT the one that I actually used on this project. The one I used had a 10mm bore. I had a brain-fart, and thought I had measured the motor shaft to be 10mm, but it was actually 9mm. Looking after-the-fact, the pulley was not available with a 9mm bore. I temporarily made a bushing out of 0.5mm shim stock, but will have to get a "real" bushing for it. A .500" bore will make it easier to make your own bushing.
FYI, the P/N of the pulley with the 10mm bore is A 6A 4M12DF12510.

I used a broach because I found out it was available to me, but I had originally planned on just drilling a 5mm hole @ 15mm off center before boring it out to 30mm, then file it square.