[SRL790]

Just to tidy it up.  Probably only took about 3-4 thou off it.

Andy

[ERC]

Nice job on the tool looks just like the one Hitchcocks and CMW sells.  ERC

[barenekd]

I always heated the head to about 300 degrees in an oven, and cooled the guides in a freezer, or when I was working in an aircraft engine shop, cooled with with liquid nitrogen. Very light tapping drove the guides in. Some would even drop in. The same with the new seats. Then the guides were reamed to the proper size and the new seats ground true to the new guides. then they were hand cut to the proper angles and widths for the curve.
Bare

[SRL790]

I had to use the boiling method rather than the oven.  The Wife was at home. 

Andy

[Ice]

cooled with with liquid nitrogen. Very light tapping drove the guides in. Some would even drop in.

 We used liquid Co2 straight from the fire extinguisher or a block of dry ice when we couldn't get access to liquid Nitrogen.

[barenekd]

I had to use the boiling method rather than the oven.  The Wife was at home.  Grin

Boil it in oil instead. You can easily get cooking oil up to 350 degrees. Water is going to be 212 unless you do something bizarre to it.
Let's put it this way, you shouldn't have to hammer the hell out of new guides like the guy in the video was going. Ya wanna crack a head, have at it.Even if you don't crack the head you are displacing a bit of metal by compressing it, and the next set or even this new set, of guides may literally fall out.
Also get the guides as cold as you can.
Bare

[SRL790]

I have an old "Frydaddy" in my shop that works pretty good for bearings and smaller stuff.  Yes I did put the guides in the freezer.