Couple of things you should check:
Cleanliness of collets- any debris or burrs could prevent you from tightening down evenly on your bit or collets.
Diameter of bits- some lower cost bits have undersized shanks that are smaller diameters than 1/4 inch. These can prevent collets from tightening properly because they can't go that small.
Use two wrenches to tighten- I always feel more secure tightening a bit with two wrenches (if it is an option) than the spindle lock.
Don't bottom out your bits- Leave a little gap under your bits when tightening them down so the collet and bits can be pulled into the spindle and compressed.
Broken collet- After a few years with my first Porter Cable router, the collet developed a crack and lost its usefullness. Less than $10 to replace.
Don't rule out a manufacturer defect- If you try everything else, contact the manufacturer. Quality manufacturers should be more than happy to help you out.
***SAFETY FIRST*** if you are using that router in a table- when a bit comes loose it comes up out of a table. NEVER put your hand over the path of a bit when plowing a groove or dado.
Just a couple of thoughts, hope they help!
Cleanliness of collets- any debris or burrs could prevent you from tightening down evenly on your bit or collets.
Diameter of bits- some lower cost bits have undersized shanks that are smaller diameters than 1/4 inch. These can prevent collets from tightening properly because they can't go that small.
Use two wrenches to tighten- I always feel more secure tightening a bit with two wrenches (if it is an option) than the spindle lock.
Don't bottom out your bits- Leave a little gap under your bits when tightening them down so the collet and bits can be pulled into the spindle and compressed.
Broken collet- After a few years with my first Porter Cable router, the collet developed a crack and lost its usefullness. Less than $10 to replace.
Don't rule out a manufacturer defect- If you try everything else, contact the manufacturer. Quality manufacturers should be more than happy to help you out.
***SAFETY FIRST*** if you are using that router in a table- when a bit comes loose it comes up out of a table. NEVER put your hand over the path of a bit when plowing a groove or dado.
Just a couple of thoughts, hope they help!
