Tips for Hand-Held Router Work
So far I've not been impressed by any of the spiral cutters I've tried - the two flute seem to be faster and the spirals tend to burn up. I've also had problems overloading the 3-1/4HP routers in the shop cutting too fast for two long and them start smoking - this from sub $200 Hitachi and Freud routers - I know PC routers are said to be the best but is the 3-1/4HP really worth $350?
From my experiences so far it seems the smaller the cutter is the less stressful on the router but cuts slow. I've tried a big bit that cuts fast but is really hard on the router and also cause a lot of chatter and vibration. What would be a good bit for one pass cutting in 3/4 sheet goods? What about a bit for cutting through 1" to 1-1/2" hardwood?
Whenever you try to take a full pass you’re going to have the problems mentioned. You’re removing so much material you have to go slowly, but going slowly causes the router bits to burn and therefore dull quicker. Plus the problems with tearout as you mentioned. I would recommend either cutting the bulk of your waste first or cutting in multiple passes. There are plenty of bits out there that can do a one pass cut, think CNC routers. I just don't know how many pattern type bits there are that will do it. Hopefully someone else may have more experience to offer.
From contributor R:
Add a spiral cutter head to your shaper with a rub bearing. I have a 2" Grizzly that hogs material like you wouldn't believe. Make a jig with toggle clamps for holding the material.
From contributor A:
The older Hitachi 3 1/4 hp routers were as good as any PC made. They were a little rough around the edges, but plenty of power. If you want fast cutting use less teeth, if you want nice finish use more teeth. Just like a tablesaw blade. The trick to avoiding endgrain tearout is to take multiple passes while climb cutting. You can cook a solid carbide bit very easily by going too slow. They are really designed for CNC routers which cut around 70 ft per minute (planers run 16-32 ft/min).
From the original questioner:
I use the bandsaw and router table method as mentioned but the situations when I'm having the problems occur with big pieces that are too awkward to handle in a stationary machine. The method I like to reproduce matching large radii is a 2" flat aluminum circle cutting jig - different holes down the jig for inside/outside cuts and you fasten down the sheet in the waste. One pass is fast but the newer Hitachi and Freud routers don't like that. They tend to start smoking. Making multiple passes in this situation means you have to sand the edges of these large pieces because of the ridges of the multiple cuts, one pass produces a good square flat edge.
Solid wood parts I always make multiple passes, but again I have to deal with the ridges and tearout. How deep would you consider maxing out a 1/2 diameter bit in say poplar per pass? What situation do you start fooling with the router's variable speed? I can't really think I've ever had a reason to turn one down besides lately when flush trimming over metal laminate to not scratch them. They seem too loose and there is too much speed under load if I turn them down and it tends to burn very easily. Wouldn't you burn up the router and probably the tool if you used something designed for CNC?
From contributor A:
I would encourage you to use MDF as a template material. It has lots of glue however cabinet ply's glue lines tend to really chew into the carbide. I would try using a 3/8" (1/2" shank)single edge router bit. This removes the least amount of material the fastest. The only reason to ever turn the router speed down is size/weight of the cutter. The router will not spin a big raised panel cutter at 20k.
Carbide lasts a lot longer on shaper cutters versus router bits. The carbide is harder on the router bits, however they usually get cooked by incorrect feed speeds. This quickly dulls the carbide edge. Shaper cutters rarely get cooked. "Wouldn't you burn up the router and probably the tool if you used something designed for CNC?" I'm guessing this was directed at my comment. Many of the solid carbide sheer/spiral bits were originally made for CNC. They do not always perform as well at lower feed speeds.
From contributor D:
I do a lot of template copying in solid wood, plywood and MDF with shapers and routers. I always rough cut my parts on a bandsaw to 1/8" oversize first. This may seem like an extra step and waste of time, but the results are much better. Not only can you route faster, but you'll spend way less time cleaning up burn marks, chatter, and splintery edges. It's also a lot easier on your tools. I have routers and bits that are over 20 years old that I still use regularly. For solid wood over 3/4" thick I use a shaper with a spiral insert cutterhead. I use a table mounted router with a Her-Saf compression trimmer for almost everything else. I made my router table with 2 fold up extension wings, so when I need it, I have a table surface that's 8' long.
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