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+-- Thread: What am I doing incorrectly with this guide bushing? (/showthread.php?tid=7368535)
What am I doing incorrectly with this guide bushing? - ®smpr_fi_mac® - 04-06-2022
This is the second Bosch RA1113 bushing that I've destroyed. 1/2" straight bit. 17/32" ID on the bushing.
I used the centering cone and *thought* the subbase was centered.
Bit is apparently hitting the guide and tearing it off.
Help?
Oh, here's the jig I'm using. Trying to cut mortices in the ends of a table top for floating tenons.
https://youtu.be/Bx1Mg2mTMO0
RE: What am I doing incorrectly with this guide bushing? - greenacres2 - 04-07-2022
Might be as simple as tight clearances. A 1/32” total provides only 1/64” margin on a side. Doesn’t take much runout to cause interference. And it’s combined runout of bit, collet, bushing and faceplate. I’d try a little more difference between bit & bushing.
Earl
RE: What am I doing incorrectly with this guide bushing? - KC - 04-07-2022
(04-06-2022, 09:46 PM)®smpr_fi_mac® Wrote: This is the second Bosch RA1113 bushing that I've destroyed. 1/2" straight bit. 17/32" ID on the bushing.
I used the centering cone and *thought* the subbase was centered.
Bit is apparently hitting the guide and tearing it off.
Help?
Oh, here's the jig I'm using. Trying to cut mortices in the ends of a table top for floating tenons.
https://youtu.be/Bx1Mg2mTMO0
Is that a DeWalt 621? If so, mine is off center just a wee bit. Supplemental bases (two from Pat Warner and one from Amazon) are also off.
For whatever that may be worth.
RE: What am I doing incorrectly with this guide bushing? - ®smpr_fi_mac® - 04-07-2022
Okay, cool.
Looks like I'll have to use the larger OD/ID bushing to hog out the waste and then go back and clear it the final 1/16" with a chisel. Slow, but feasible.
KC, it's a Bosch MR23EVS.
RE: What am I doing incorrectly with this guide bushing? - OneStaple - 04-07-2022
I agree on the too little clearance assessment. Also, any torque you put on the bushing while routing might be enough to use up that 1/64" clearance (max, if everything is aligned perfectly) and create contact.
Tyler
RE: What am I doing incorrectly with this guide bushing? - Willyou - 04-07-2022
I don't disagree with the above clearance comments. And this is just a opinion based on looking at pictures. So, I could be way off base. The Bosch guide bushing appears to be made with the bushing cylinder swedged into a flat plate. It looks like the swedged end has pulled loose from the plate. It could be caused by contact with the cutter. I don't know. But, it seems to me, that method of manufacture leaves possibilities of bending, flexing, loosening, etc. I like the Porter Cable guide bushings which are machined from a solid piece of steel or brass. You could use these, but you will probably have to also change the plastic base plate. This is not a big deal; easy to make from 1/4" acrylic.
RE: What am I doing incorrectly with this guide bushing? - ®smpr_fi_mac® - 04-07-2022
(04-07-2022, 08:24 AM)OneStaple Wrote: I agree on the too little clearance assessment. Also, any torque you put on the bushing while routing might be enough to use up that 1/64" clearance (max, if everything is aligned perfectly) and create contact.
Tyler
Yeah, I agree, too. Lesson learned!
(04-07-2022, 09:32 AM)Willyou Wrote: I don't disagree with the above clearance comments. And this is just a opinion based on looking at pictures. So, I could be way off base. The Bosch guide bushing appears to be made with the bushing cylinder swedged into a flat plate. It looks like the swedged end has pulled loose from the plate. It could be caused by contact with the cutter. I don't know. But, it seems to me, that method of manufacture leaves possibilities of bending, flexing, loosening, etc. I like the Porter Cable guide bushings which are machined from a solid piece of steel or brass. You could use these, but you will probably have to also change the plastic base plate. This is not a big deal; easy to make from 1/4" acrylic.
This was mentioned by a friend of mine. After this project is done I'll buy the PC bushings.
Yeah, the guide is swedged to the plate.
RE: What am I doing incorrectly with this guide bushing? - jteneyck - 04-07-2022
(04-06-2022, 09:46 PM)®smpr_fi_mac® Wrote: This is the second Bosch RA1113 bushing that I've destroyed. 1/2" straight bit. 17/32" ID on the bushing.
I used the centering cone and *thought* the subbase was centered.
Bit is apparently hitting the guide and tearing it off.
Help?
Oh, here's the jig I'm using. Trying to cut mortices in the ends of a table top for floating tenons.
https://youtu.be/Bx1Mg2mTMO
Nevermind. Can't seem to delete this.
John