[Vwdiesel] Cleaning threads for head bolts

[engle31 at comcast.net]

I'm doing a partial rebuild of the 1.6na for my caddy project. I already replaced the rings and started the reassembly process. I have the head cleaned up and ready for the install with the new head gasket. I want to make sure that the bolt holes in the block are cleaned out but I don't have a tap to chase the threads. I have compressed air but was curious if I absolutely need to get the correct tap to ensure the threads are clean. I thought a heard you could make a tap-like tool from an old head bolt. Is this true and if so is it just a matter of cutting a few grooves in the threads of the old headbolt?

Also when installing the new headbolts, are they supposed to install dry(no lube)?

Thanks in Advance

Paul in PA