Modifications to a Lee 6 cavity mold for easier sprue cutting

[jonk]

Someone asked me to post how I do this in another thread, and I thought it deserved one of its own.

A little background.

The Lee 6 cavity mold (if you've never used one) doesn't have a spot on the sprue cutting plate to hit it with a hammer or rod. Rather, it has a cam lever with it's own handle to cut the sprue. This is a fine idea in principle, but I always found that the travel of the cam was insufficient to entirely cut the sprue, meaning you still had to bang on the sprue plate with a wooden mallet (minus a good place to do it!) To add insult to injury, if you pull on it TOO hard, you either pull the handle off the cam, or you snap the pot metal the cam is made of.

One day by accident, when the nut that holds the bolt to the sprue plate and cam assembly was loose, I accidentally made a discovery. If the cam travels entirely underneath the plate, rather than hitting its pre-designed stop, it does just what it SHOULD do- namely cuts the sprue completely.

I set out to modify a 6 cavity mold to do this as a matter of principle. Pics follow. One note: if you go to the hardware store you can probably speed this up, I used what I had at hand.

HOW THINGS SIT TO START

http://i9.photobucket.com/albums/a67/jonklei/SAM_2238_zpsyllwxfh7.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2238_zpsyllwxfh7.jpg.html)

Note in this picture the cutout in the cam lever.
http://i9.photobucket.com/albums/a67/jonklei/SAM_2239_zpswwqwspla.jpg


Now here is the cam lever opened. All the way. It hits the built in milled stop and won't open any more. Note how the cutter holes are open only ever so slightly. This is what causes the issue.
(http://s9.photobucket.com/user/jonklei/media/SAM_2239_zpswwqwspla.jpg.html)http://i9.photobucket.com/albums/a67/jonklei/SAM_2240_zpsgdjglqlo.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2240_zpsgdjglqlo.jpg.html)

Here's another view from the side. Also note that the existing bolt isn't really long enough as things sit.
http://i9.photobucket.com/albums/a67/jonklei/SAM_2241_zpsty2jdtnd.jpg

[jonk]

From the underside. Again, this is the normal state of affairs:
http://i9.photobucket.com/albums/a67/jonklei/SAM_2243_zpshcms7825.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2243_zpshcms7825.jpg.html)

Now in this picture, I have loosened the nut a little more to recreate my initial accidental discovery. This is what we WANT to happen, to have the cam run UNDER the sprue plate.
http://i9.photobucket.com/albums/a67/jonklei/SAM_2242_zpsbchu9cbg.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2242_zpsbchu9cbg.jpg.html)

The question is, how to do this?

Well, the obvious answer is a longer bolt; this poses two problems. The first is that Lee made the cutout in the cam lever in the first place. What we want to do is make a spacer to fit in the area indicated, to get the cam lever lower, to clear UNDER the plate.
http://i9.photobucket.com/albums/a67/jonklei/SAM_2244_zpsxgoqd0re.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2244_zpsxgoqd0re.jpg.html)

That's easy enough. The other issue however is that the bolt isn't a standard bolt at all, but a stepped bolt, where the fat part doesn't even go all the way through the plate. And, the plate is drilled to accept just this smaller diameter.
http://i9.photobucket.com/albums/a67/jonklei/SAM_2245_zpsebqgmivp.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2245_zpsebqgmivp.jpg.html)
So you can't just get a longer bolt, or it will slop around in the cam lever. You have to drill out the plate itself.

Incidentally a .315" drill bit is the diameter of the cam lever hole, and the diameter you want to enlarge the hole in the sprue plate to.

[jonk]

Here is a comparison of the hole sizes:
http://i9.photobucket.com/albums/a67/jonklei/SAM_2246_zps5blwa7ms.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2246_zps5blwa7ms.jpg.html)

Here is the plate after I drilled it out:
http://i9.photobucket.com/albums/a67/jonklei/SAM_2247_zpsgmjljzwx.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2247_zpsgmjljzwx.jpg.html)

Now on to making the spacer that will fit the cut out.

You want a thickness that brings the cut out up to the same height as the non-cut out part of the cam lever. I didn't have a washer that small, so here is one I modified to fit the space in question. I actually later had to do a little more work to clear the mold when the whole thing closed.
http://i9.photobucket.com/albums/a67/jonklei/SAM_2249_zpsces0b7hq.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2249_zpsces0b7hq.jpg.html)

More or less in place:
http://i9.photobucket.com/albums/a67/jonklei/SAM_2250_zpsiypizifw.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2250_zpsiypizifw.jpg.html)

[jonk]

This is what I meant when I said you may have to do some more grinding on the washer to clear the mold... or just go out and buy a thick small diameter washer with a .315" hole in it.
http://i9.photobucket.com/albums/a67/jonklei/SAM_2251_zpsdpbuygkx.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2251_zpsdpbuygkx.jpg.html)

After that, I simply ran a bolt through the whole lot, and tightened it up. Here we have again how we want it to look:
http://i9.photobucket.com/albums/a67/jonklei/SAM_2252_zpsqme2gdil.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2252_zpsqme2gdil.jpg.html)

Side view. Note the location of the spacer.:
http://i9.photobucket.com/albums/a67/jonklei/SAM_2253_zpsnrryqdjf.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2253_zpsnrryqdjf.jpg.html)

Another side view:
http://i9.photobucket.com/albums/a67/jonklei/SAM_2255_zpskpamuteo.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2255_zpskpamuteo.jpg.html)

[jonk]

As seen here, the longer bolt also lets you use a lock washer, so the thing doesn't get loose all the time- also a problem of the Lee design.
http://i9.photobucket.com/albums/a67/jonklei/SAM_2256_zpsu1wjaeb2.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2256_zpsu1wjaeb2.jpg.html)

Finally here it is opened fully NOW. Compare that to the initial "open" pic, and you can see the advantage that we have.
http://i9.photobucket.com/albums/a67/jonklei/SAM_2258_zpsobfxer3l.jpg (http://s9.photobucket.com/user/jonklei/media/SAM_2258_zpsobfxer3l.jpg.html)

So that's it. Took about 20 minutes even with having to grind down the washer (and a little bit of the bolt, too, as it was a fat headed one), but if you bought the parts, it would take about 3 minutes to do. It ends the difficulties of cutting sprues entirely with the Lee 6 cavity molds. Even if the mold is cold.

[Randall]

Thanks for the write up and photos jonk. I'm going to modify mine as well. Great idea by the way.

Randall