Another query about Makita router/trimmer drops down in base!

Hi, I have the MAKITA RT0702CX2 - I’m doing some dovetail joins at the moment so the router needs to be really accurate. No problems fixing the router bit in the collet, that’s completely secure but I line up the depth in the base (17mm depth which is what the dovetail jig requires) start routing and when I check it’s dropped by a couple of mm. Can’t work out if the base is sticking or how to fix it? Have rung and emailed Makita but no-one has got back to me so far. Thanks!

Are you using the trimmer base or the plunge base?

I would have thought the trimmer base is not man enough for the job because of the profile of a dovetail router bit. I would imagine that there would be a downward force trying to pull the router bit down because the cutting blades of the bit are not parallel. This downward force probably pulls on the gearing in the trimmer base. This rack and gear mechanism may have some play between the teeth of the mechanism and only relying on the locking leaver mechanism to hold it in place which may not be sufficient.

You could try increasing the grip of the trimmer base locking leaver by adjusting the locknut on the mechanism. Adjust this nut when the leaver is released.

Alternatively, use the plunge base which is far more rigid. The trimmer base is only really intend for parallel cuts and not for the extra forces present when cutting dovetails. With this you can set a secure depth stop.

I don’t have a plunge base so that may be the problem, tightening the lock lever helped inititially but not for long. I think I’ll need to invest in the base - or a bigger plunge router for dovetailing! Thanks for the advice.