I need to cut twenty-four, 1/2″ wide x 2-1/2″ long x 1-1/2″ deep mortises in 3″ depth yellow pine. I’m using a new 1/2″ Delta mortise bit (the one that comes with the Delta mortise kit) in a Delta 16-1/2″ variable speed drill press. All adjustments such as ejection slot orientation, bit clearance, etc. have been carefully made per Delta’s recommendation, and rechecked. When the bit is ejecting chips properly, the bit cuts quickly and smoothly. Unfortunately, more times than not, the chips compress together in the lower part of the chisel requiring the bit to be removed for cleaning. I have tried various speeds between 800 and 1500, with the higher speed seeming to work somewhat better – but not a lot. Since I am unfamiliar with this operation, I don’t know if it’s the bit, the speed, the type of wood, the feed rate or some other ‘operator error’. Any helpful comments will be appreciated.
Discussion Forum
Get It All!
UNLIMITED Membership is like taking a master class in woodworking for less than $10 a month.
Start Your Free TrialCategories
Discussion Forum
Digital Plans Library
Member exclusive! – Plans for everyone – from beginners to experts – right at your fingertips.
Highlights
-
Shape Your Skills
when you sign up for our emails
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. -
Shop Talk Live Podcast -
Our favorite articles and videos -
E-Learning Courses from Fine Woodworking
-
-
Replies
I think it my be a combination of all those . i would do half the depth in one pass first. Pine tends to get rather gummy,plus your width of mortise may also come onto play.
Although I have a dedicated mortise machine and have only come across this problem with a fast feed rate / dull chisel/ bit.
You also have to remember your ejecting alot of material through a small opening, and the shavings are rather coarse..
Good luck..
Thanks spiff - I tried really slowing down the speed rate, and it seemed to help some. Still got bogged up on the 3rd hold, though. I read a couple of things some time ago that I'm not sure how to do. One was to 'debur' the bit. I would try that if I knew how. Also, I once read that it helped to do some 'pre-drilling' but I wouldn't know what size bit to use - or if there the location of the drilling within the mortise area is important. Finally, I'm wondering if some type of 'lubricant' on the bit - such as might be used on a table-top, could help.
"I'm wondering if some type of 'lubricant' on the bit " Grab some PAM anti-stick cooking spray out of the kitchen and give it a try. Light coat. Can't hurt. Works well on bandsaw and scroll saw blades.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Have a can of Boeshield T9. Think I'll give that a try first. Maybe PAM if that doesn't work. Thanks!
I picked the PAM idea up from one of the bandsaw blade manufacturers.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
Edited 1/17/2005 6:19 pm ET by forestgirl
This forum post is now archived. Commenting has been disabled