I finally made a pair of spacer blocks to use with one of my circular
saws; another case in which I have "discovered" a technique first
discovered a century or so ago. I made them out of scrap oak.
http://www.flickr.com/photos/gdguarino/6970896957/in/photostream/lightbox/
They proved very handy, making my setups both quicker and less prone to
error. But it occurs to me that I have made a measurement device out of
absorbent material. Should I worry? I'm not using them to line up a
surgery laser, and they are only 3" long, but I'm wondering what you
more experienced folks do. Make them from plastic? Finish the blocks? Or
not worry as the expansion and contraction (in the with-the-grain
direction) is negligible over such a small distance?
On 3/19/2012 11:17 AM, Greg Guarino wrote:
> I finally made a pair of spacer blocks to use with one of my circular saws;
> another case in which I have "discovered" a technique first discovered a
> century or so ago. I made them out of scrap oak.
>
> http://www.flickr.com/photos/gdguarino/6970896957/in/photostream/lightbox/
>
> They proved very handy, making my setups both quicker and less prone to
> error. But it occurs to me that I have made a measurement device out of
> absorbent material. Should I worry? I'm not using them to line up a surgery
> laser, and they are only 3" long, but I'm wondering what you more
> experienced folks do. Make them from plastic? Finish the blocks? Or not
> worry as the expansion and contraction (in the with-the-grain direction) is
> negligible over such a small distance?
Old wheels you've rediscovered there. The easy way out is to use precision
setup blocks. Example:
http://www.amazon.com/1-2-3-Blocks-Pair/dp/B00092CJC6/ref=pd_bxgy_hi_text_b
They are also available in brass or aluminum (probably plastic too) and in
metric and smaller sizes if you look around. Machinists all over the world
use them so they are a commodity item and relatively cheap. Same thing when
you decide to use sanding-paper sharpening -- buy a granite flat plate from
your machinist supply house and you have something _really_ flat to work
from which is better and is probably cheaper than having plate glass cut.
dadiOH wrote:
> Greg Guarino wrote:
>> I finally made a pair of spacer blocks to use with one of my circular
>> saws; another case in which I have "discovered" a technique first
>> discovered a century or so ago. I made them out of scrap oak.
>>
>> http://www.flickr.com/photos/gdguarino/6970896957/in/photostream/lightbox/
>>
>> They proved very handy, making my setups both quicker and less prone
>> to error. But it occurs to me that I have made a measurement device
>> out of absorbent material. Should I worry? I'm not using them to line
>> up a surgery laser, and they are only 3" long, but I'm wondering what
>> you more experienced folks do. Make them from plastic? Finish the
>> blocks? Or not worry as the expansion and contraction (in the
>> with-the-grain direction) is negligible over such a small distance?
>
> Don't worry.
> ______________
>
> You might want to consider making a guide with auto spacing so you don't
> have to mess with separate blocks and straight edge...
>
> 1. Fasten something like a 1x2 to a piece of 1/4" hardboard that is wider
> than your saw is from blade edge to shoe edge.
>
> 2. Run your saw down the 1x2, cutting off the excess hardboard.
>
> You lose 1/4" of cutting depth, no big deal IMO.
>
> You can refine it by fastening another 1x2 under the thing at 90 degrees to
> the other 1x2. That is used to square the cut jig to the work. The jig can
> be any length you want... if mostly cross cutting sheet goods, 48"+ is
> handy.
>
> You can make jigs in the same manner to guide a router. You have to always
> use the same diameter bit as that used when you cut off the excess
> hardboard.
>
I made mine using a length of U channel aluminum (from Lowes) fastened
to a piece of 3/16 Plywood using flat head (countersunk) bolts. Make
sure you leave a tab on the other side of the guide for placing the
clamps. If accuracy is required, the guide needs to be placed on the
good side of the cut, otherwise the result will be a saw blade
thickness narrower.
I have one 8 foot one and one 4 foot one and have used them for years.
Picture on ABPW.
--
Gerald Ross
A harp is a nude piano.
On 3/19/2012 9:17 AM, Greg Guarino wrote:
> I finally made a pair of spacer blocks to use with one of my circular
> saws; another case in which I have "discovered" a technique first
> discovered a century or so ago. I made them out of scrap oak.
>
> http://www.flickr.com/photos/gdguarino/6970896957/in/photostream/lightbox/
>
> They proved very handy, making my setups both quicker and less prone to
> error. But it occurs to me that I have made a measurement device out of
> absorbent material. Should I worry? I'm not using them to line up a
> surgery laser, and they are only 3" long, but I'm wondering what you
> more experienced folks do. Make them from plastic? Finish the blocks? Or
> not worry as the expansion and contraction (in the with-the-grain
> direction) is negligible over such a small distance?
Longitudinal expansion is negligible. Depending upon the species and
cut, it might be 0.1% to 0.3% of radial or tangential expansion.
--
www.eWoodShop.com
Last update: 4/15/2010
KarlCaillouet@ (the obvious)
http://gplus.to/eWoodShop
Greg Guarino wrote:
> I finally made a pair of spacer blocks to use with one of my circular
> saws; another case in which I have "discovered" a technique first
> discovered a century or so ago. I made them out of scrap oak.
>
> http://www.flickr.com/photos/gdguarino/6970896957/in/photostream/lightbox/
>
> They proved very handy, making my setups both quicker and less prone
> to error. But it occurs to me that I have made a measurement device
> out of absorbent material. Should I worry? I'm not using them to line
> up a surgery laser, and they are only 3" long, but I'm wondering what
> you more experienced folks do. Make them from plastic? Finish the
> blocks? Or not worry as the expansion and contraction (in the
> with-the-grain direction) is negligible over such a small distance?
Don't worry.
______________
You might want to consider making a guide with auto spacing so you don't
have to mess with separate blocks and straight edge...
1. Fasten something like a 1x2 to a piece of 1/4" hardboard that is wider
than your saw is from blade edge to shoe edge.
2. Run your saw down the 1x2, cutting off the excess hardboard.
You lose 1/4" of cutting depth, no big deal IMO.
You can refine it by fastening another 1x2 under the thing at 90 degrees to
the other 1x2. That is used to square the cut jig to the work. The jig can
be any length you want... if mostly cross cutting sheet goods, 48"+ is
handy.
You can make jigs in the same manner to guide a router. You have to always
use the same diameter bit as that used when you cut off the excess
hardboard.
--
dadiOH
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