Tear out question

What's Hot
JayceeJaycee Frets: 287
edited December 2019 in Making & Modding
Ash body and walnut body with tear out. 
I made myself a table router as It will be more stable than using it in the conventional way when routing asround the body.
I also bought a new router bit.
I know tear-out comes with the build but I was wondering if I was maybe doing something wrong with my new setup. 
The bit was rotating at a high speed, and I was "feathering" the horns when machining them, and not taking off too much on each pass. This would be my usual way of rouing the body.

I had a few "kicks"  which jolted the body quite a few inches away from the bit.  I interpreted this as the body not being held firmly enough and I was letting the router dictate rather than me.

If any one can give me a few pointers as I have two nice tops to route later on. Thanks
Anyway some pics.......




0reaction image LOL 0reaction image Wow! 0reaction image Wisdom

Comments

  • JayceeJaycee Frets: 287
    edited December 2019
  • RolandRoland Frets: 8592






    Tree recycler, and guitarist with  https://www.undercoversband.com/.
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom
  • FunkfingersFunkfingers Frets: 14324
    Jaycee said:
    I was wondering if I was maybe doing something wrong with my new setup?
    Is a Black & Decker Workmate, standing on an uneven garden path, a stable enough platform for the task? 
    Be seeing you.
    0reaction image LOL 0reaction image Wow! 1reaction image Wisdom
  • Are you using a template, @Jaycee ?  Assuming so, how much overhang is there of the blank beyond the template?
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom
  • KalimnaKalimna Frets: 1534
    To me, that looks less like tearout than it does inadvertently taking a huge bite.
    Tearout should be an absolute minimum with shear cutters. I'd also echo comment re:workmate as table.
    If you have the template, just d/s tape it to the blank and have the template underneath and hand-rout against the template. Harder for me to describe than it is to do.
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom
  • TTonyTTony Frets: 27346
    Is this the problem when there’s a conflict between matching the direction of router travel with the direction of spin of the cutter with the direction of the grain of the wood?


    Having trouble posting images here?  This might help.
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom
  • JayceeJaycee Frets: 287
    Thanks for the pics @Roland
    Jaycee said:
    I was wondering if I was maybe doing something wrong with my new setup?
    Is a Black & Decker Workmate, standing on an uneven garden path, a stable enough platform for the task? 

    That was a concern but it was stable enough no complaints there.

    Are you using a template, @Jaycee ?  Assuming so, how much overhang is there of the blank beyond the template?
    I thought about that overnight and I think that was my problem, I was using a template and the overhand was a bit to much on certain parts. 
    Both guitars have tops to go on and if I remember correctly I may have glued the routed tops on the body blanks first, used them as the template which would give some support to the tear out prone sections of the body.

    I think both bodies are redeemable. 

    Thanks for the replys
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom
  • GSPBASSESGSPBASSES Frets: 2335
    edited January 2020 tFB Trader

    I'm not sure if using a Black and Decker workmate as a router bench would be stable enough, any slight movement of the bench could easily cause a snatch that could results in a tear out.

    It's very important when band sawing the body blank to cut as close to the line as possible, I try to cut within 1mm to 2mm of the line. A tip that might help you, I use the same 19mm down cut router bits as you, but when I do the 1st cut I use a 22mm bearing instead of the 19mm bearing for the first cut, I then use the 19mm cutter with the 19mm bearing to finish, see photo below.  

    The reason for doing it this way, the first cut will remove any wood that you might have left on by cutting too far away from the cutline on the bandsaw, also when you come to do the final cut you are only removing 1mm of wood. This greatly reduces the chance of snatching which virtually eliminates tear out, and of course gives you a very smooth finish. It's also very important when doing this type of routing never hesitate, try to keep the feed speed constant, any hesitation or stopping while doing the cut can easily cause a snatch, or worse still snatch the body out of your hands sending it flying across the workshop.

    I do most of my routing on an overhead pin router, I still use the 22mm bearing for the first cut then go to the 19mm. I also use ½” triple Helix spiral cutters on the pin router, these do not have bearings but a pin set in the bench. I still use the same principle, an oversized pin to start with normally, 15mm for the first cut then a 13mm pin for the final cut. Some woods where the grain is going in all directions I use a 14mm pin on the final cut that leaves me about 1/2mm to take off on the final sanding.




    This is how I've mounted my router under the bench. The yellow one not the black ones.


     In this photo you can see the router cutter sticking through the bench, it does wind down beneath the bench when not in use.

    Your life will improve when you realise it’s better to be alone than chase people who do not really care about you. Saying YES to happiness means learning to say NO to things and people that stress you out.

    https://www.facebook.com/grahame.pollard.39/

    0reaction image LOL 1reaction image Wow! 2reaction image Wisdom
  • JayceeJaycee Frets: 287
    GSPBASSES said:
     A tip that might help you, I use the same 19mm down cut router bits as you, but when I do the 1st cut I use a 22mm bearing instead of the 19mm bearing for the first cut, I then use the 19mm cutter with the 19mm bearing to finish, see photo below.  



    I had forgotton that tip.   :/   I remember you saying that on my last bass build. I used it when using a round over bit, and it worked a treat.  ................I don't think I will forget it again .... =)

    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom
Sign In or Register to comment.