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Hey guys, wondering about some bits and feed rates for Purple Heart. Making a memorial plaque for a friends father who just passed away so I just finished designing it and it’s going to use all the purple heart I have on hand so I don’t have any test pieces and I am kind of rushed on it. I just have never done a project with such a hard wood before.
I will be using a 45 degree v-bit for some engraving, then a .25" bit for cutting out a section for a photo to go into.
Looking for suggestions on feed rates. I will probably play it safe and do .075 depth per pass, it wont be a big plaque so it wont add much time to do a few extra passes. For the .25" I have a 2 flute downward spiral and a 2 flute straight bit. I assume 1 on the Dewalt RPM, I have the X steel bar stiff mod.
Purpleheart is some of the hardest wood I have cut.
For a 0.25" endmill I cut at 0.07 depth of cut with about a 45IPM feedrate.
The 45 degree v-bit is what size? Go slow for v-carving text in purpleheart, I usually run the same toolpath twice and I get a nice clean cut. For a 60 degree 0.25" v-bit I cut at 40IPM.
Well quick update , broke two 30 degree engraving bits… I think first one was maybe little to fast of feed rates, second was my fault with not getting all the metal out from the first bit… Able to recover and on the final carve now…
Now the question is finish… Do I try n paint the letters or just finish with some laqour? Iv never done the sanding sealer paint method before so I’d hate to ruin it.
I would just oil it. Purple heart itself just looks beautiful. As light hits it over time it will lose its color. So if the letter’s don’t get as much UV exposure they will be darker than the surface over time.
I can’t say I have done the sanding sealer method before, but something similar. 2 coats shellac, paint, sand (100 grit), more shellac. Here is an example on grainy oak.
If you are more concerned you can keep adding shellac before paint.
I think I was only set at 40in/min, not sure what happened. I changed it down to 30 and it carved the rest no problem until I hit the tip from the first bit lol
yes, and way too fast on the rpms
1 on the Dewalt is 16k prms
The Dewalt is great but it’s lowest speed makes it tricky. Sometimes you have to find your range, either go shallow and really fast or adjust deeper and slower.
