Veritas Router - Blade slipping; cuts too deep

[Paul-in-Plymouth]

It’s hard to understand the depth of cut increasing.  I think the suggestion that you left some slack between the flange of the depth-adjustment nut and the recessed ring at the top at the blade might make sense if the depth got shorter.  Getting longer is really puzzling.  

Is there some way you can be advancing the depth-adjust nut as you plane?  Maybe, as Derek says in his 2nd comment, the locking screw on the shackle doesn’t pull the V-insert back hard enough to prevent the blade assembly from some slight rotation.  And something in the act of planing causes the rotation to advance the adjustment nut.  

Maybe something has been distorted through usage and no longer immobilizes the shaft of the blade in the shackle.  There is brass, steel and aluminum in that assembly.  I’d look first at how well tightening the screw at the back of the shackle immobilizes the blade to rotation.

Derek’s 1st comment does not describe the construction of my plane.  Mine has the brass locking screw  going into  the back of the shackle.  But then a spring-loaded steel spud is inserted concentric in the shaft of the brass screw to engage the backside of the V-insert in the shackle.   Mine doesn’t have a wave-washer for tension, as far as I can see; it has a compression spring coiled around the steel spud.

[Strokes77]

Mine is as you describe Paul. There is no washer on mine, I took a picture and but can't post from my phone.

Also I confirmed again that it slips in use. Regular use, not dropping it on the ground. And I tightened that nut as tight as my fingers would let me. It does not wobble or move around side to side at all, but it slips up or down. Also If I set the router plane down naturally in a smooth motion it will cause the blade to lessen its cut.

I'll call LV when I get a chance.

[Admiral]

I've never had that issue with the large router.  Sounds like the missing washer.

[Strokes77]

This is my Lock screw or whatever it's called.



This is the clamp that it screws in to.  


I thought this was going to be an easy solution.  I guess maybe not, I'll call LV tomorrow.

[Paul-in-Plymouth]

Your parts look like mine. 

Your observation that you have vertical play of the blade relative to the body indicates your blade is not fully immobilized in the shackle by the the locking screw.   

I did the following:  I snugged the locking screw down and advanced the depth-adjust screw to take out the backlash.  Ready to make a cut - blade immobilized; no play.  Then I backed off on the locking screw a little.  Immediately, there was ~10 mils of vertical play between the flange on the depth-adjustment nut and the recessed “engagement ring” on the blade shaft.  The blade could move up and down that amount.

Suggests to me that there’s some dimensional issue in the shackle/lockdown-screw assembly that prevents fully locking your blade down. 

Let us know what LV says.

[Derek Cohen]

For those jumping to the last post to see a solution, I have edited my last post with a fix.

Regards from Perth

Derek

[Paul-in-Plymouth]

I think what Derek is saying is that if for some reason the piston gets prematurely hung up in its cylinder in the brass screw as you tighten, then it may make you think it’s fully bottomed out before it really is.  Then the blade would appear to be firmly clamped in place, but may not be secure.  If it later worked free of its hang-up while you are planing, then the blade would no longer be firmly clamped down.  It could then dive into your work, deeper than you’d intended.

I think that’s a plausible explanation for what you’ve reported.  It may do that because the brass cylinder has become distorted through use.  In that case lubrication might help, but it also might not completely solve the problem.  You may need a new brass lockdown screw assembly.

[Strokes77]

When it does slip, it doesn't loosen enough that it continues to slip.  Does that make sense?  Like, if it slips, it's still tight enough that it doesn't feel loose.  It's not as if something breaks loose and now it's wobbly.  It is still locked down as tight as it will go, the blade has is just cutting deeper.

[Derek Cohen]

Try some penetrating oil to loosen the piston. It sounds like it is stuck.

Regards from Perth

Derek

[Paul-in-Plymouth]

Do you detect any tendency of the piston to get hung up on the walls of its brass cylinder as you work it in and out by hand?  I think that's the key point of Derek's suggestion.  

If not, then I'd be back looking for some dimensional issue involving distortion or wear, where snugging down the lock-down screw does not, in fact, fully lock the blade down.  The assembly has a train of brass and steel parts constrained by a (beefy-seeming) aluminum part.  Is something distorted or worn?

I think LV is the best bet for an answer.  I have not observed this with my plane with a lot of hard use.