Please do not pot this tiny guide and images outside of the lockpicking101 forum. Thanks.
A very simple DIY practice/cutaway pin tumbler lock that will take only 10 minutes to complete. As a newbie picker, the purpose was to allow me some small visual help in picking without altering the feel of the lock.
I apologize for the poor photo quality.

Materials:
-Lock
-Pins
Tools:
-Hack saw/Hand held rotary tool
-Pliers/vice
-Marker
Procedure:
1.
Take apart the lock as so: viewtopic.php?t=10505
So that what remains is the plug and tumbler (housing).

2.
If your plug housing has metal strip to hold the pins in then remove it. This is done so that after the cutting is finished you can smooth the inside of the pin shafts with a coat hanger or small chain saw file.

If your tumbler is a solid piece you can either cut the top off (lots of work) or use a small Allan key or similar to smooth the inside of shafts via small cuts you will be making.
3.
Make a mark along the side of the pin tubes where you want to cut. I used my smallest driver pin to guide me on where to cut. I tried to avoid cutting too low as it may affect the shear point of the lock. My cuts were a little conservative; you can be adventurous and cut lower if you want to see the driver pins closer to the shear point. It’s your call.

4.
Put your safety glasses on and hope that your dremel at 11:30pm won’t wake up the landlord next door…….lol.
You have many options with how you cut this as you can cut one or more slits horizontally along the tumbler, cut slits vertically per pin shaft or cut a big chunk out of the side. It depends on the tumbler design, your tools, how much lock “feel†you want to sacrifice and of course your patience. Again you choose as this is not a tried and tested procedure.
Use pliers or a vice to give the tumbler your desired cuts.
As you can see, I went for two cuts and my lowest cut being about 1mm – 1.5mm above the shear line.

CAUTION: The tumblers are a cast metal (either a brass, steel or other alloy) and tend to behave differently from other things you may have cut. Also when you hit the pin tubes you will get plenty of hot metal kick back.
5.
Put it all together and start picking. Hold the tumbler as if you were picking a pad lock.

I hope this helps and I hope others will try to improve this method.
Cheers!!