Author Topic: rabbeting bit with short bearing?  (Read 777 times)

0 Members and 1 Guest are viewing this topic.

Offline mrFinpgh

  • Posts: 388
rabbeting bit with short bearing?
« on: October 28, 2019, 08:34 PM »
I'm working on a project that requires two rabbets stacked on one another.

I made the first rabbet 5/8" deep and 3/8" wide, and then tried to make another rabbet referenced off of the first rabbet's wall.  That rabbet would work out to be 5/16" deep and 3/4" wide.  What I've discovered is that when I try to run my rabbeting bit against the 5/8" deep rabbet it only works to about 3/16, and then the screw at the end of the bit (holding the bearing in place) begins to rub the corner of the joint and the next rabbet is further offset.

Are there rabbeting bits that can do this?

Other idea was to use a pattern bit and just hot glue some MDF to outline the pattern.

Any other solutions I could look at?

Thanks,
Adam

Festool USA does not pre-approve the contents of this website nor endorse the application or use of any Festool product in any way other than in the manner described in the Festool Instruction Manual. To reduce the risk of serious injury and/or damage to your Festool product, always read, understand and follow all warnings and instructions in your Festool product's Instruction Manual. Although Festool strives for accuracy in the website material, the website may contain inaccuracies. Festool makes no representations about the accuracy, reliability, completeness or timeliness of the material on this website or about the results to be obtained from using the website. Festool and its affiliates cannot be responsible for improper postings or your reliance on the website's material. Your use of any material contained on this website is entirely at your own risk. The content contained on this site is provided for informational purposes only and does not constitute professional advice.


Offline SRSemenza

  • Global Moderator
  • *
  • Posts: 9204
  • Finger Lakes Region, NY State , USA
Re: rabbeting bit with short bearing?
« Reply #1 on: October 29, 2019, 01:32 AM »
I take it the piece is not open ended? Or is already assembled?  Otherwise you could set it up on a router table with a straight  cut bit or probably the rabbeting bit with the bearing and washers removed.

Not sure if they exist for rabbeting bits  but maybe a bit that uses a pilot instead of a bearing would be short enough? Or maybe there is a pilot that  would fit your bit?

Seth

Offline Peter Parfitt

  • Magazine/Blog Author
  • *
  • Posts: 4269
    • New Brit Workshop on YouTube
Re: rabbeting bit with short bearing?
« Reply #2 on: October 29, 2019, 04:27 AM »
You can get bits that have a selection of bearing sizes so that the rabbet is just as you need. I think Whiteside will have some of these.

Start with the top rabbet (which I assume is the wider one) and do the narrower rabbet second. That way you can reference off the same face of your stock and not be limited by the depth of rabbet when done the other way around.

Peter

Offline RKA

  • Posts: 1916
Re: rabbeting bit with short bearing?
« Reply #3 on: October 29, 2019, 06:31 AM »
Pictures or even a sketch would really help.
-Raj

Offline SRSemenza

  • Global Moderator
  • *
  • Posts: 9204
  • Finger Lakes Region, NY State , USA
Re: rabbeting bit with short bearing?
« Reply #4 on: October 29, 2019, 11:15 AM »
Pretty sure ............................  it is not the  width  of the rabbet, as in adjustable bearings, but that the bearing  / bearing screw is hitting the surface under the bit.  In most situations you can just raise the work piece off the bench. But in this case the work piece itself is in the way.

Here is a picture of something that I did that I believe is similar to the Adam's situation. Two rabbets like steps. In my picture the lower step is a separate surface (talking about the double lip around the inside edge of the tray) but in his case the two steps are both rabbets.




Seth
« Last Edit: October 29, 2019, 11:18 AM by SRSemenza »

Offline SRSemenza

  • Global Moderator
  • *
  • Posts: 9204
  • Finger Lakes Region, NY State , USA
Re: rabbeting bit with short bearing?
« Reply #5 on: October 29, 2019, 11:39 AM »
I take it the piece is not open ended? Or is already assembled?  Otherwise you could set it up on a router table with a straight  cut bit or probably the rabbeting bit with the bearing and washers removed.

Not sure if they exist for rabbeting bits  but maybe a bit that uses a pilot instead of a bearing would be short enough? Or maybe there is a pilot that  would fit your bit?

Seth


    The pilot I am referring to is not a panel pilot bit , but a guide pilot that works in the same way a bearing works. It just attached to the bit shaft. It does not roll. Here is a picture of one. Not sure if there is a bit available for the OP's situation. But if so, the length of the pilot is probably shorter than a bearing with a screw. And might not contact the surface below.

  Herer is a link with some good pictures.


  So far though, searches have not shown one that could make a rabbet.


Seth


                   
« Last Edit: October 29, 2019, 11:50 AM by SRSemenza »

Offline RustE

  • Posts: 435
Re: rabbeting bit with short bearing?
« Reply #6 on: October 29, 2019, 11:55 AM »
Changing from a socket-head cap screw to a pan-head or truss-head machine screw will gain some clearance.  Maybe 1/16” or so.  Not sure that will be enough for this scenario.

Offline SRSemenza

  • Global Moderator
  • *
  • Posts: 9204
  • Finger Lakes Region, NY State , USA
Re: rabbeting bit with short bearing?
« Reply #7 on: October 29, 2019, 12:01 PM »
Changing from a socket-head cap screw to a pan-head or truss-head machine screw will gain some clearance.  Maybe 1/16” or so.  Not sure that will be enough for this scenario.


That's one I need to remember.  [thumbs up]

Seth

Offline mrFinpgh

  • Posts: 388
Re: rabbeting bit with short bearing?
« Reply #8 on: November 01, 2019, 01:53 PM »
I take it the piece is not open ended? Or is already assembled?  Otherwise you could set it up on a router table with a straight  cut bit or probably the rabbeting bit with the bearing and washers removed.

Not sure if they exist for rabbeting bits  but maybe a bit that uses a pilot instead of a bearing would be short enough? Or maybe there is a pilot that  would fit your bit?

Seth

Already assembled.  I ended up using a 1/4" pattern bit in my little router to take out the last 1/8" of material, referencing it off the wall of the upper rabbet.   

It's exactly as you described with the double lip.  The width issue was not a problem.

Best,
Adam

Offline mrFinpgh

  • Posts: 388
Re: rabbeting bit with short bearing?
« Reply #9 on: November 01, 2019, 01:57 PM »
You can get bits that have a selection of bearing sizes so that the rabbet is just as you need. I think Whiteside will have some of these.

Start with the top rabbet (which I assume is the wider one) and do the narrower rabbet second. That way you can reference off the same face of your stock and not be limited by the depth of rabbet when done the other way around.

Peter

I probably could have done it this way (3/4" rabbet, then 3/8" rabbet beneath. Unfortunately, I was going off the basis of someone's plans and they had outlined to do 2 rabbets in the manner described, so I didn't really think about it beyond the basic process.

As mentioned above, my solution was to use a small 1/4" depth pattern bit to do the remainder of the upper rabbet, referecing the bearing off the already removed part.  Of course, my issues with bearing heights struck again and I plowed out a 1" chunk as I didn't set the bit deep enough to begin.   

That's what creative inlays are for, though  8)

The rabbeting bit i have does have the bearings for different widths.

Best,
Adam



Offline mrFinpgh

  • Posts: 388
Re: rabbeting bit with short bearing?
« Reply #10 on: November 01, 2019, 01:57 PM »
Changing from a socket-head cap screw to a pan-head or truss-head machine screw will gain some clearance.  Maybe 1/16” or so.  Not sure that will be enough for this scenario.

Interesting.. I will keep that in my back pocket for the future.  thanks!