I received my platen chiller and flat platen from Nathan on Friday. I've been struggling with keeping my flat platen cool for some time now. Up 'til now, that meant putting ice in my cooling bucket and stopping every few minutes so I could use a sponge to cool the platen with the ice water. Some belts get very unhappy when wet, so I often had to remove the belt when doing this. It drove me crazy!
I had planned on fabricating a platen chiller based on Chuck Bybee's recommendation. But I am no machinist. So when Nathan offered these, I jumped on it!
Yesterday I went to Home Depot to get an extra 5-gallon bucket, some hose, and some 1/4" npt fittings. Then I drove over to Harbor Freight to buy their
264 GPH submersible pump for a staggering $13. I had no idea if this pump would provide enough volume to effectively cool, but this is more of a "proof-of-concept" pump that will likely be replaced anyway.
Using a 1" & 1/2" small wheel, I ground a couple of reliefs in the top of both the lid and the bucket to allow the power cord and output hose to exit the bucket. I then drilled and tapped a 1/2" hole in the side of the bucket for the water return hose.
It works! And it works very, very well. I worked on cleaning up the flats of a small batch of heat-treated knives today and I was astonished at how cool both the platen and the knives remained. There were times when I had the KMG cranked up to 100% and grinding
hard. After several minutes I turned the grinder off and felt the platen. No heat.
None. This was using Nathan's A2 platen, but without any thermal grease as I haven't gotten any yet. The mating surfaces of the platen and chiller are perfectly flat, so there was great heat transfer.
I also tried the chiller on my old platen, which ceased being flat a loooong time ago. Because of this, the mating between the chiller and platen wasn't as perfect as it was when using Nathan's platen. After some very hard grinding, I stopped to check and this time I did detect a very small amount of warmth. But I had to touch the platen for a few seconds to really detect it. If I had touched the platen for several seconds before using the chiller, I likely would have needed to break out the trauma kit for a burn dressing!
Thank you, Nathan. You did a great job with these.
Here are some photos I took last night when I set everything up.
Here's a shot of the water returning to the bucket. As stated above, the 264 GPH seemed more than ample.
Fortunately, I already had my tooling-arm rack in the perfect spot. I built this rack out of scrap lumber when I first got my KMG, thinking it would be temporary. But it's holding up surprisingly well.
Here's a shot taken today while I was grinding with it. The pump ran for about 2.5 hours without issue. I need to figure out a better way to turn it on/off. Right now I just have to plug/unplug it. Any suggestions?
It's kinda hard to see, but there is a cool vortex in the water when the pump is first turned on.
Here's the batch I was working on today. 3 in O1, 2 in CPM154, and one in 440C.
