Posted: Wed Jan 27, 2010 12:55 pm
Don't you just hate when you can't edit the title?
OK as can be expected we all have opinions on the subject and as such I'm going to give you mine.
First "zero" is not the same for all of us. I have never found a number as to what the the slot width/length should be to the blade, perhaps someone some place has done so. From practical experience I have blades from about .093" to .125" and given a bit of wobble due to things beyond our control a given slot might be slightly wider.
A little math tells you that is about 1/32". Now if you line up the starting point of your cuts the line of the cut will start very nearly at the same place each time. The extra cut away by a wider blade is towards the edge that is away from the headstock. But the shopsmith has a quill so you can always center the thinner blade in the wider slot. Yes they do get damaged and they do need replacements from time to time. You can always move them on for use with dado blades...
For all but a few times in my whole woodworking experience have I found it necessary to change inserts because of problems caused by normal blade width issues. I might be so bold as to say 99.6% of the time you will not notice the difference between zero and say a smaller width blade in a wider blade kerf in the insert. The length of the slot in the insert seems to not matter at all. A few times with some very splintery wood I did need to work in a almost zero zone, just doesn't happen often with me.
Since I have not used all the wood in the world or done all the cutting that mixes that might result from blade differences I can not say that all will have seen the same results I have.
So far we have talked about regular saw blades, this changes when you get to dado blades and molding cutters. Now a lot more of a custom design is required if the zci function is needed.
Depending on what you are doing you might not need a special insert other then the ones that shopsmith sells. I personally own the full set inserts and a couple of the zci that shopsmith sells. The zci seems a lot to pay for what it gets you. They are simple to build out of cheap materials in most cases, but do take some time so you have to decide what your time is worth.
I have built some replaceable strip zci for my older 500 but found I needed to have thicker material and the design stated to become to complex to make it worth the effort in comparison to just make a full insert out of cheap materials. Once you have a pattern and a router set up they only take a few minutes to make and it is easy to make 10-12 of them in a half hour.
The 520's insert is a bit different and I have plans to build a version that takes inserts for that. I have the sketch up drawings done and have the blank stock cut to length and width but was unable to start the routing last fall before it got to cold. It is a more complex design to meet my perceived needs.
I don't see any easy way to make one of these adjustable but if someone can then I say go for it. For now I thing replaceable is about all I'm after.
Ed
OK as can be expected we all have opinions on the subject and as such I'm going to give you mine.
First "zero" is not the same for all of us. I have never found a number as to what the the slot width/length should be to the blade, perhaps someone some place has done so. From practical experience I have blades from about .093" to .125" and given a bit of wobble due to things beyond our control a given slot might be slightly wider.
A little math tells you that is about 1/32". Now if you line up the starting point of your cuts the line of the cut will start very nearly at the same place each time. The extra cut away by a wider blade is towards the edge that is away from the headstock. But the shopsmith has a quill so you can always center the thinner blade in the wider slot. Yes they do get damaged and they do need replacements from time to time. You can always move them on for use with dado blades...
For all but a few times in my whole woodworking experience have I found it necessary to change inserts because of problems caused by normal blade width issues. I might be so bold as to say 99.6% of the time you will not notice the difference between zero and say a smaller width blade in a wider blade kerf in the insert. The length of the slot in the insert seems to not matter at all. A few times with some very splintery wood I did need to work in a almost zero zone, just doesn't happen often with me.
Since I have not used all the wood in the world or done all the cutting that mixes that might result from blade differences I can not say that all will have seen the same results I have.
So far we have talked about regular saw blades, this changes when you get to dado blades and molding cutters. Now a lot more of a custom design is required if the zci function is needed.
Depending on what you are doing you might not need a special insert other then the ones that shopsmith sells. I personally own the full set inserts and a couple of the zci that shopsmith sells. The zci seems a lot to pay for what it gets you. They are simple to build out of cheap materials in most cases, but do take some time so you have to decide what your time is worth.
I have built some replaceable strip zci for my older 500 but found I needed to have thicker material and the design stated to become to complex to make it worth the effort in comparison to just make a full insert out of cheap materials. Once you have a pattern and a router set up they only take a few minutes to make and it is easy to make 10-12 of them in a half hour.
The 520's insert is a bit different and I have plans to build a version that takes inserts for that. I have the sketch up drawings done and have the blank stock cut to length and width but was unable to start the routing last fall before it got to cold. It is a more complex design to meet my perceived needs.
I don't see any easy way to make one of these adjustable but if someone can then I say go for it. For now I thing replaceable is about all I'm after.
Ed