So I ended up getting the McFly in the 1/4" shank, and I started using it for cleaning my epoxy. I tried pouring epoxy on a carve in red oak but it soaked into the wood almost 1/4" down! No matter, I decided to use the mcfly to remove a few layers, but I ended up having burn marks on it. I used the recommended settings (18k RPM, .02 DOC), and then I tried to speed up the velocity on the cut (not the RPM), but the burn marks still showed up.
I have a pic and the cut file… any thoughts would be appreciated!
You can also try removing the underside cutter inserts - that’s what I did on mine to decrease the chances of burning & remove a source of friction from the rubbing. They don’t really get a chance to actually cut anything & I don’t think I noticed any change in surface smoothness.
The 3d Stepover says .50 (I just used the default settings that came with Carbide Create). My issue also seems to be lines in the wood. If you notice next to the burned wood, there a lines going down the wood that are created by the bit. I can’t get rid of them. Should I be going across the grain or with the grain when using the McFly? Would that do anything?
I go with the grain. Just seemed logical.
I know the spindle is not perpendicular to the wood until I face the second side.
I do get a slight line no matter, so the spindle is not perfectly set. Light sanding removes the effect.
Okay, good to know. Yeah, I’d call it a slight line as well, it just annoys me, lol. I get more fuzzies with a 3/4" endmill, but fewer lines… not sure which one i like better. I thought going with the grain made sense too… who knows maybe I’ll see what happens if I go against.
I use the McFly all the time for surfacing. When surfacing an epoxy cut out I use .01 DOC at 200 IPM and 18000 RPM. I could cut deeper per pass, but I like to do small bits at a time so that I don’t cut into the wood. I was hesitant about cutting too deep/ fast but I have have recently been doing 0.04" DOC at 170 IPM in walnut with no issue. I could probably go deeper/faster but I don’t want to push things.
Go with the grain. Lines will be much worse cutting across grain. You could try rotating the stock 90° and cutting with the grain.
If your tram is out in one direction you will get scallops cutting that way, and steps cutting the other.
I think 18000 is too fast for a 1" cutter. Try 10000 - 12000, and the feedrate as fast as it will go.
I had this happen to my mcfly. I had dull carbide inserts. They were so dull that it actually stalled my spindle during a conservative facing operation. I would take a look to see if you need to rotate some of those inserts.
To keep epoxy from spreading, spray the wood with spray shellac. I use that for initial pours with zero bleed into the wood. I also use the shellac between pours where I add a new color that touches the last pour. It prevents the new epoxy from dissolving the old pour and possibly blurring the lines.
I’ve been testing different methods - so far I’ve used sanding sealer, spray shellac, and polyurethane. The sanding sealer worked well on smaller cuts on mahogany, but the shellac barely worked on red oak. I’m wondering if it’s the type of epoxy as well, maybe the viscosity affects how well it sinks into the grain? I used sanding sealer on a larger pour onto walnut and that worked, but there was a little bleeding. I think I’m going to try the poly on several types and see how it goes.
For the cutter - I took off 2 of the inserts, but it didn’t fix it. I think there may be a misalignment issue, I have to look more closely at the cutter to see what I can figure out.
I bought some UV activated epoxy a few months back in the hopes of faster drying times. It was a dismal failure for what I was doing at the time. I added black dye and the surface would harden but not underneath. I set the stuff aside.
I have seen people talk about brushing in a light coat of clear epoxy to prevent bleeding but I never tried that as I didn’t want to wait the additional time.
Fast forward to this past weekend where I carved out a pocket and wanted to fill it with white epoxy that I was carving in to later. I got out the clear UV stuff and brushed it on with a small acid brush and then hit it with the UV light. Within a couple of minutes it was hard so I could proceed with the white pour.
Maybe not good depending on your use case but at least I have found something I can do with the rest of that bottle
Water diluted white Elmer’s glue works very well and dries quick depending on how thick you brush it on and ambient conditions. ~10-20 mins here in arid Colorado. A hot air gun/hair dryer would speed that up to just a few minutes. And the water to glue ratio doesn’t need to be precise, just add water to the glue until it is a workable consistency suitable for your project. For me, that is somewhere around 25-40% water. Hope that helps.
I am facing some Red Oak today, and it was leaving burn marks. The wood was from the center of the tree and the color is darker than what I normally see.
The cutters are still sharp ( finger nail test).
So I tried @Tod1d suggestion for Feed ( 120 ipm ) and Speed (12 k), from 60ipm and 18k rpm.
This improved the burning to a point.
The real gain was going from a DOC of .015 to .030 .
The chips looked better as well and I can feel the temperature difference in the wood as well.
Similar to other recommendations, I’d try trading depth of cut for speed.
Also however, I would recommend removing the inserts on the bottom of the McFly, leaving only the ones that are perpendicular to the surface of the wood. (Not sure which the OP removed) When taking deeper cuts, the inserts on the bottom don’t clear as well, allowing dust to build up and generate more friction/heat under the cutter.
