Thread: GMC 1500w Router: Fine height adjustment

I'm no expert by any means and I've not seen that model router but from what I have seen and if I'm understanding your question correctly then fine adjustment only works on the stop depth and if you have your router locked then it cannot move.

Hi Mychael, and thanks for your reply.
Perhaps photos can explain my problem better: The first photo is of my Hitachi router.
Attachment 177882

On this router, TWO locking levers can be seen. The one on the left is the main locking lever, while the right-hand lever works on the fine adjustment rack. With both levers disengaged, the router base can be pushed by hand to the approximate cutting depth required. That adjustment can then be held by activating the right-hand lever. This brings a pinion into contact with the silver rack, and, by turning the knob at the top of the router, allows FINE adjustment of the cutting depth. When the EXACT cutting depth is set, it can be locked firmly in place by the left-hand lever, which locks the sliding posts. It seems a very effective system, is easily usable in a router table, and I can understand the process!

The second photo is of the GMC 1500W router:
Attachment 177883

This router has ONE locking lever which locks the sliding posts so as to set the cutting depth. However, the large knob at the top is described in the manual as the Micrometer Adjustment Knob, which is to be used for making FINE adjustments. However, the manual gives no advice about how to use that knob for that purpose. Whether the locking lever is engaged or disengaged, turning the knob seems to have no effect. I am hoping that someone who has used this router has figured out the fine adjustment process: it remains a mystery to me!

Thanks for the photo's. So turning the knob on the GMC changes nothing? Does not even extended the thread down further onto the depth stop?

On my router which only has the single lock ,it calls the screw adjuster a fine depth adjustment also but all it in fact does is raise or lower the screw stop that touches the turret which sets the depth limit of the plunge.

The plunge depth of both routers is set by an adjustable rod (with fine adjustment) that, when the router is plunged, is pushed down onto a stop turret. This seems to be a fairly standard function on most plunge routers. In each photo, this plunge depth adjustment is located on the reverse side of the left-hand sliding column. It works well on both routers, but is a completely separate function from incremental adjustment of the cutting height, something that is nearly essential when the router is mounted in a table. I repeat: the large knob on top of the GMC router, labelled in the manual as Micrometer Adjustment, seemingly does nothing. Which is surprising.

I've got the same router and it does work, but it is a bit time consuming to use.

If it has been screwed the wrong way the thread becomes disengaged. I think I pulled mine apart and got it working.

The frustrating thing about the fine adjustment is that it takes so long to adjust. You unlock the level, the router base is extended, then you have the screw the fine adjustment in until you get the required height. The you decide to change the router bit, so have to unscrew the fine adjustment all the way back so get the base to extend.

I ended up abandoning using the fine adjustment and instead unlock the level, then adjust the screw stop on the other side, then compress and try to tighten. After a while you become good and doing it in the table.

Router has proven to be quite hardy. Not a patch on my Makita 3600B but still ok for table based use. The collet can be a bit dodgy as well, so take care if using for a 1/2 to 1/4" reduction.

Cheers,

Tom

Hi, Tom.
I must say that that routine for Fine adjustment had not occurred to me. The fact that the Micrometer Adjustment Knob on my router does NOT alter the cutting height despite the base being at full extension probably means that it has been detached from the internal nut. Even if it were working, the process you describe certainly seems tedious. I'll take your advice and use the plunge rod for fine adjustment of the cutting height.
Thanks for your help.
Adeben