Is it possible to do a single-pass profile cut on 3/4” birch plywood with a 1/4” compression bit using the Makita router? Or would that just be asking for (best case) a burned up router?
If yes, how slow would I need to set the feed rate? (Journeyman Elite)
A couple extra passes is way faster than driving to the store to buy a new sheet of plywood, a new router, or new bits.
Hey LoneCarver,
the Makita hand trim router is a universal motor (= a commutated series-wound motor) which is a type of motor that gets hotter the slower it runs. And it is slowed down by a high mechanical load, e.g. by
See here for a diagram of motor characteristics:
The secret of using the hand trim router is to give it a mechanical load so that it stays in the nominal load (nominal torque/speed pairing), which limits it to a specific speed (unlike a spindle, which can deliver its high torque over a wide speed range that you can select from, often from 6000–24000 rpm).
See router/spindle comparison.
When milling wood, you need high torque AND high speed, so if you use a universal motor and no spindle, the universal motor should be chosen to have its nominal torque at a high speed, e.g. by using one of the best milling motor solution for hobbyists and semiprofessionals.
Thanks for the detailed response.
Agreed. I’m still pretty new at this, and have spent more time up front getting proficient with my CAD/CAM. But that’s why I asked rather than just going for it. 
I do single pass in 3/4" with an 1/8" compression bit all the time. 60-80 ipm
feed,40-50 plunge, #3 on the Makita. Ramp your cut.
Single pass ramp cuts?
Yes Sir, works great.
I think he’s asking about cutting through 3/4" at full depth.
Will it work? Maybe. Will the cut quality look like dog sh**? Absolutely. Will you drastically reduce the life of your bits and router? Most definitely.
I’m just sharing what works for me. I get totally acceptable cut quality, bits last a long time for me and an 1/8" bit puts a minimal load on the router. As they say on the internet, your mileage may vary…
I don’t mean to be pedantic but you’re ramping your cuts. That is not a single pass per the poster’s question.
Not sure why ramping into your cut isn’t a single pass unless you’re being incredibly pedantic. Most of us would likely consider multiple passes to be multiple trips along the cut line with the depth increasing with each trip around (pass). A ramp adds a small amount of extra distance to the cut as it starts & comes around.
Pretty sure that’s nearly as meaningful a difference as the added time that three quarter-inch deep trips (passes) take. Unless the OP was suggesting that anything less than a full-depth plunge was necessary for his use case.
This is where I wash my hands. Perhaps the original poster can clarify the question for you.
Hey all,
the original poster focused on what you can do with the hand trim router to not overload it. The correct answer would be, try it out by selecting a balance of the parameters feed rate and depth of cut and then make sure the router is not slowed down by the load. I would start with a high (rotational) speed as the problem with milling wood is heat, and this is usually avoided by high speed.
By the way, the seller of Rich’s bit writes:
Suggested feed and speed :
Wood 11,000-16,000RPM , 50-70ipm if full depth
*machines have different rigidity so please try 2 passes at 1/2 depth first to have an initial witness cut before pushing it hard
Also this is a very thin bit, so you don’t exaggerate with feedrate. Probably the reason that it is sold in packs of five pieces 
I’ve rarely broken a bit using these settings. Almost all breakage was due to hitting fasteners or knots so operator error!
I agree a ramp would leave a small section of the cut not at full depth as it travels along the vector a short distance until it reaches full depth.