More Engine Valve Chasing Tools

I wrote a little bit about making chasing tools from engine valves on August 2011

http://persimmonforge.blogspot.com/2011/08/engine-valve-tools.html

After making four larger curved chisels I decided to make a miniature set too.  

I keep an assortment of partially prepared tool blanks of various tool steel origin and can quickly select a size and shape I need.  In this case I chose envying valve stems.  I’d already cut off the flare end with a Zip disc.  I’m not sure of the alloy but think it may be EV-8 stainless steel  http://www.motor.com/article.asp?article_ID=1792

http://www.enginetech.com/rebuilder-valves.php There may be a difference in alloy between intake and exhaust valves.

At a near lemon heat this steel is still difficult to forge.  It seems to be air hardening and usually does not need any other heat treatment.  I forged the tips in four different radius swage gutters to establish the outside radius and did the finishing with grinding tools.  The cutting edge has a low angle to keep the tip strong.  For the job I have in mind (carving a die face) a shallow depth cut will be fine.

It’s about an 80/20 or higher chance the edge will be hard enough without some heat treatment.  If, after a quick test the edge is blunting, I polish it again and torch heat the 1/4” adjacent to the tip and oil quench.  That process has a nearly 100% success rate.

Engine Valve Tools

I made two punch tools last week and each was dedicated to a small project. I’ve mentioned my affinity for making dedicated tools, jigs and templates which are stored as a group related to each repeated project. In these cases each punch had a round taper to make a 3/16” hole. I made each of them from one half of an engine valve shaft and welded a short utility handle.

I have used this valve stock for quite a while to make chasing tools and drifts and have been impressed how well they hold an edge and shape. I always thought there were some variety of stainless steel which was air hardening until I found the article below. I’ve never had to buy any as the auto mechanics seem to be quite free with giving used ones away.

I made one punch just by grinding on a zirconium sanding belt and the other by torch heating and forging the taper and then grinding to finish. I keep a batch of utility handles ready to use so making the punches and welding the handles took a total of about 5 minutes maybe ten if I count the time spent stamping the names on the handle labels. That seems like a good investment for tools which I anticipate will last for years.

Nice reference about engine valve alloys:

http://www.enginebuildermag.com/Article/2564/valve_alloyswhat_makes_them_so_special.aspx

http://www.persimmonforge.com/