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Posted: Tue Feb 26, 2013 10:45 am
by fjimp
marvin wrote:Al & Dusty Boy you guys are quick.
I appreciate the response. I think these should solve my problem. I already have some of the T slot washers but couldn't figure out how to use them. I did go to the HD for some carriage bolts but could not see how to tighten them once the tall fence covered the rip fence.
I generally counter sink the bolts.
Posted: Tue Feb 26, 2013 11:02 am
by mountainbreeze
Just curious...
What is the purpose of the "wrap-around" portion if the sacrificial part is attached to the fence with T-Nuts?
Posted: Tue Feb 26, 2013 11:05 am
by dusty
marvin wrote:Al & Dusty Boy you guys are quick.
I appreciate the response. I think these should solve my problem. I already have some of the T slot washers but couldn't figure out how to use them. I did go to the HD for some carriage bolts but could not see how to tighten them once the tall fence covered the rip fence.
I suspect that we are not singing from the same hymnal.
Carriage bolts will not work in the normal fashion with the t-nut that I am using.
The t-nuts that I get
from Shopsmith slide into the t-track on the fence and the bolt that secures it all together inserted through a countershunk hole in the fence.
[ATTACH]20354[/ATTACH]
This is the t-nut that I am using.
Hope this clears any confusion I have caused.
Posted: Tue Feb 26, 2013 11:23 am
by Ed in Tampa
For a sacrificial fence and sacrificial being the key word here I simply clamp a board to the fence bury the blade or cutter as deep into the board as I need it and tose the whole thing when I'm done.
Actually I'm too cheap to tose the board so I keep it and use it again by slidding it to a new surface if I need to bury a cutter into again.
Long time ago I was cutting something using a aux fence, I had cut into the aux fence on another project. This time I wasn't I was just using the fence. Long story short the piece I was feeding against the fence caught on the trailing edge of the cut area and before I could correct it the board I was cutting was ruined. Learned right then and there never to spend much time building SACRIFICIAL Fences since I couldn't trust them to reuse them again.
Posted: Tue Feb 26, 2013 11:43 am
by dusty
We (I) have been referring to the subject fence as "sacrificial" but actually what I have been representing is more appropriately called an "auxillary" fence.
The only time I use a fence in the sacrificial manner is with a dado blade when cutting rabbets.
Posted: Tue Feb 26, 2013 10:54 pm
by marvin
I like all of these suggestions. Actually what I did (as some suggested) was clamp a piece of 2X4 to the shopsmith fence. The clamps I used do tend to get in the way.
I then used two T nuts and button head screws to fasten the 2X4 to the business side of the fence. That will work for a while but I will pursue a more elegant solution if I find I need this type of fence more often.
Posted: Wed Feb 27, 2013 6:20 am
by dusty
marvin wrote:I need to build a sacrificial fence for molding. I see the sketch in the PTWfE
4th edition page 68, but I do not see how to fasten that to the 520 fence. I have no holes in my fence and do not wish to drill any.
I wouldn't think that a 2x4 provided straight enough surface to be used as a fence for making molding. But...whatever. It certainly is sacrificial.
Posted: Wed Feb 27, 2013 8:08 am
by reible
Hi,
I have several fence attachments and use various methods of attachments.
The 520 fence with t-slots really is useful for attaching them and pretty easy to do.
Keep in mind you will have to do few measurements, first from table top to center of the t-nut and then you have to get the depth of the counter bore correct. It has to be deep enough so the head of the screw is lower then the face of the "fence". The next part is to determine what length of fastener will be used. It has to be long enough to engage the threads of the t-nut but not so long as to extend much through the t-nut.
For a lot of applications 3/4" stock works well and since it is sacrificial you don't want to spend to much time on prep but you do need to make sure it is not going to cause problems so inspection is need of the raw piece. Flat and no bows, twists, cups that sort of thing. Plywood, MDF, UHMW plastic can be used as well as scrap wood of most kinds.
For certain times you might need something wider, wide dado's, molding, and even router/shaper applications. A simple solution I use is a fir 2x4, with additional prep work done to it. I slab off a bottom then use that as a flat and slab off the two sides, joint as needed and you have a width of about 1-1/4" that will work for most other projects.
For routing/shaping where the bit/cutter needs be embedded in the fence I have an "H" fence that I use. BTW I'll be making a 2.0 version of this sometime this year and if I can I will share it here.
Ed