To hold the spare belt, I will be coming off the 5/8" cord support column with two accurately spaced 1/4" tubes, which will be held in place by (2) 4-40 cap head screws and washers. The washers are larger than the 1/4" tubes and this should retain the belt.
Over the last few days, I have been wondering if this saw would accurately cut my exposure plates. Dremel support told me that the diamond blade cannot be used to cut glass, but I have read online, that some people have cut glass with this blade. Perhaps that is the standard Dremel support answer for that question, due to liability issues and health risks. However, if it can cut glass, that would make my process much easier, and it would not make it anymore dangerous than the current method I have for making accurate plates.
Here are some photos for the spare belt holder. All I need now is a spare belt and blade , besides the power supply. I intentionally gave the belt a a little slack, just to preserve it, but it is not going to slide off.
Only three more items to go and I can start using my new saw
Since I am taking a break, I will briefly discuss these items in the order that I plan to tackle them.
Calibrating The Saw - Before drilling any holes in my table top, I put a lot of thought into saw calibration. During the fabrication of the shaft mounts, I tried to make them as accurate as possible, but considering the machinery available, needless to say they are not perfect. However, the width of the mounts are identical at the right angle and the drilling for the shafts was based upon this width, and the mounts were positioned according to this width. The problem now becomes aligning the shafts according to the mounts, but hopefully the shaft holes in the mounts will be close enough to allow easy and proper alignment.
Cut The Blade Notch - Blades will be attached and detached with the saw in the rest position, with the saw assembly pushed to the rearmost travel position. To allow easy attachment and detachment, I will be cutting a 1/8" wide X 7/8" long X 1/16" deep notch into the table top under the blade area. Additionally, this notch will allow me to use the saw to cut the saw travel path within the table top, without disturbing the saw alignment, since the notch will provide a recess below the depth of cut.
Cut The Saw Travel Path Into The Table Top - Considering I will be powering up the saw for this procedure, I suppose there were only two more items. During this process, I will be applying power to the saw, and cut the initial groove into the top. To help ensure a straight cutting path, I will probably run the path several times, with the saw running, before attempting to cut a PCB.
Such an easy phrase to say, but very difficult to achieve
I can easily obtain the full length of travel, but it is not the same smooth fluid motion, like the day after casting the carriage. I am just guessing, but I would say that either the bearings shifted slightly or I slighty bent one of my shafts during the machining process. I think 0.001 - 0.002" additional clearance between the shafts and bearings would do the trick nicely, but I really do not have the means do this accurately.
Most likely, I will mess with it a little more before doing something drastic. If that fails, I would imagine that I will purchase some 1000 and 2000 grit wet or dry sandpaper, and progressively polish the shafts (remove metal ). I am fairly certain that I can get nice motion with enough sanding, and hopefully sometime later today.
During my trials and tribulations of attempting to calibrate the saw, I had the shafts in and out numerous times, and during reinstallation of the shafts, I noticed that the fit was kind of tight. I finally got curious and wondered if this tight fit was warping my linear shafts and causing the less than perfect linear travel, so I increased the distance between the shaft mounts, and now the sliding action is much smoother.
DUH
Many hours down the drain and a lot of frustration. Lesson learned the hard way I guess I cannot complain too much, because so far this project has been pretty good to me.
Well now that I have that bug figured out, I can start the calibration process all over again
Since one of my goals for this project is to impart some knowledge of lessons I learn, I thought I would share some of my latest setbacks and advances with you.
However, please keep in mind the previous lesson, which was, do not bind the shafts by having the mounts too close, because it will distort the shafts and cause grief.
And before I proceed with this discussion, I suppose I should tell you that I have changed my plan a little. Instead of calibrating the saw, I have set my sights on achieving super smooth linear travel, because I want to just gently pull the saw through the material as I cut it.
As it stands now, as determined by math and measurements, the shafts are exactly where they should be and the carriage easily slides the full length of travel, however there is some friction during travel and I want to eliminate this friction. In all honesty, I should have purchased custom linear shafting for this project, but I have lots of shafting from various salvaged printers, and so I used some of that. However, I have had this shafting for many years and I did not properly protect it from damage, so over the years, it has received various nicks, scratches, etc... In addition to that, I now believe the shafts were originally used as rotary shafts, because upon very close inspection, rotary grooves were found on the shaft. These rotary grooves were one of the causes of friction. They were not very deep, so I just polished that area linearly with some 2000 grit sandpaper, meanwhile also removing any other imperfections that I found on the shafts. As a result of this polishing and imperfection removal, the carriage now has a much smoother travel, however I am still tracking down other sources of friction, and I imagine that I will still do some various sanding along the shafts. The 2000 grit sandpaper leaves it's own set of scratches, and I am sure this will also be a source of friction, so when I get very close to the fluid travel that I seek, I will most likely go over the entire shafts with some finer grit sand paper. If I had purchased linear shafting, I am certain the linear travel would areadly be smooth as silk.
Anyhow, I have been protecting the bronze bearings from alterations. These bronze bearings are a lot less forgiving than the UHMWPE that I used on the original saw, but I am certain that I will be much happier with the new saw, once I get the fluid action that I seek.
I suppose that a summary of this post would be that if you can afford linear shafts, just buy them, and if you salvage printer shafting, properly protect it, and last but not least, do not use rotary shafting as linear shafts, or vice versus.
I got the shafts to where I thought it was pretty close, and then I tried to polish the shafts with what I believe is #0000 FINE steel wool, but that did not help any, so then I tried crocus cloth. The crocus cloth does a really nice job of polishing out the scratches left by the 2000 grit paper. The action is getting pretty darn smooth at this point, with a little lubrication.
Although not 100% satisfied with the sliding action, I suppose 95% would best describe it, however I must say that it is pretty darn smooth. I could probably get it to 100%, but that would require removing the shafts from the mounts, and I don't want to risk it at this point. I could also probably make it much better by working on it several more hours, but I believe it is good enough for now. If it becomes a problem, I will deal with it at that point, by either purchasing some linear shafting or by removing the shafts and working on them some more.
Anyhow, while working on the shafts, I came up with a new idea for calibrating the saw. I believe this idea is easier than my last idea for calibration and I believe it should provide a much higher degree of accuracy. ACCURACY.... I know some of you are thinking that accuracy went out the window when I started sanding on the shafts, however this is not true, the shafts still mic out to 0.375", even where I sanded the hardest.
The calibration should now be a quick and easy process, and I also now have a good plan for cutting an accurate blade notch in the table, or at least I think I do
With that fine abrasive, I'm not surprised at little size change. Those materials work in the 4th and 5th digit mostly. (unless used intensely)
What you should do is obtain a precision cut piece, set the saw, and make a cut. Clamp that down, and make a series of measurements over the length of the cut to understand what your travel actually is.
Having the size of the shaft measure up doesn't necessarily pick up on it being out of square with whatever work stops you've got setup, though that one, if consistent, can be easily compensated for in the stops. It can pick up on out of round sections, but you've got to sample a lot to find those, and they are likely your friction points, so this is improving over time as you sense the motion. (generally)
The big one is non-linear travel, and the length of your bearings does allow for some curvature, and sanding may well improve movement, but increase the curvature and or slop associated with curved portions of travel made easier with the sanding.
Your cut and sample measurements will ferret this out. I would use a minimum of 10 samples per 2-4" of cut board to understand whether or not you've got a curve. Your own repeatability with standard measuring tools is going to be about .002" so take extra samples and curve fit them, if you are wanting to really get down to a few thousandths of overall accuracy. You can do this without a precision piece, if you have a height gauge and calibrated platform.
Edit: If you don't want to curve fit, an alternative to that is to cluster sample and average. At each of the 10 designated points, take a few samples close together and average them.
An alternative, that won't get you absolute kind of accuracy, but will give you some idea of curvature, is to take a piece and perform the same samples and then cut it, then compute the differences using the same fixture and measurement points.
Thanks for the compliment, however there is a flaw in the design, a complete oversight on my part, and I realized it just as soon as I drilled the holes I wish I could have a do-over
Ever since deciding to add the switching power supply, it has been my intention to cover all connections on the underside of the table top, and additionally enclose the connection area of the power supply, with the same enclosure. To make a short story short, I drilled the holes for the table top posts a 1/2" wider than the width of the power supply. Of course this is not a major problem, but it does make the construction of the cover a little more difficult and the overall fit of the cover less appealing.
Hmmmm..... Redo the table top or accept the design flaw? I think I will have to bite the bullet on this one.
@everyone
After taking a break and then getting back to the saw, being the something retentive individual that I am, I decided to rip the shafts back out and polish them well enough to get better action than the previously stated 95%. Although not 100% perfect, because of various nicks, the shafts look pretty darn good at this point and fairly well polished (nice and shiny ). I am not yet certain if it was a wise move or not, because I still need to realign the shafts and carriage, but hopefully it will be better than before I removed the shafts.
The carriage now moves a whole lot better. It is still not 100%, but very, very close, and I think I am satisfied at this point.
In additon to reworking the shafts, I have also calibrated the saw, or at least I think I have. It should be very close to perfect, but I will not know for sure, until I start cutting some board material.
So my next step is to cut the blade notch in the table, after which, I can attach the blade, power up the saw, and cut the saw travel path into the table top
While doing the layout for my blade notch, I took one additonal measurement, just to see how square the slide was to the actual table top. At both the start of travel and end of travel, for a total travel of 7-19/64", as measured from the edge of the table to the end of the rotary shaft, there was only a 0.0045" discrepancy. Since the table top is only around 15" deep, that would put me in the ballpark of around 1/128" from front to rear of table. Pretty darn close!
The slide itself, was squared and calibrated according to the fence. So apparently, the fence must be off by a SMIDGE
Perhaps I got a wee bit excited too soon Because there is good news and there is bad news. &
The weak link reared it's ugly head. When previously testing the coiled wire and pushbutton switch, I did not have the additional load of the rotary shaft attached to it. I suppose it is needless to say that this wire could not supply the necessary current. I did not melt the wire in two or anything drastic like that, although I am sure I could have, but it simply just did not rotate the motor at a sufficient speed. And of course, the bearings and rotary shaft, needed a slight break in, which did not help matters.
So in the meantime, I wired the motor directly to the battery charger with some 16 gauge wire. When I first fired it up, the RPM was inconsistent, going from high to low and back again. So I started it several times, running it several seconds and shutting it down. And now, it hums with a consistent high RPM.
After the bearing break in, I cut my groove in the table, using the heavy gauge wire. I am happy to say that the saw cut the melamine like a hot knife going through warm butter
Bad news is that I have to find a heavier gauge coiled cable, but in the meantime, the good news is that I can finely tune the saw and cut circuit board material.
Cord problem resolved and the saw is almost completely rewired with the new cord. I will post a couple of new photos tomorrow to show the new cordset.
And tomorrow, I should also be able to run a few accuracy tests, using the measurement procedure that I laid out earlier in the thread. Speaking of which, I decided not to attempt to make the edge of the table exactly 4.00" from the saw kerf. Instead I added about 1/16" to allow for discrepancies.
In addition to mic'ing the test cuts on the sides, I will also be mic'ing the corners and checking squareness with the Pythagorean Theorem.
Here are some new photos for your visual appetite. The new cord does not look as neat and professional as the first cord, but it looks decent enough and it is highly functional. The saw now runs like it was intended to and believe me, it is ready for some serious cutting.
With my new and extremely easy method of measurement, the new saw cuts highly accurate widths, when cutting from the same edge of the board. However the slide is currently not square to the fence, so cutting from opposite ends, leaves a 0.0045" discrepancy in a 1.25" span, which is no big deal, because I just need to dial it in.
Overall, I am highly please with the operation of the saw and results so far. Just a little more fine tuning, and the arguments can then begin, by those who will dispute my claims of accuracy.
I believe the saw is to the point of being highly accurate, but now I need some more raw materials to verify it 100%, because I certainly do not want to be chopping up the "good stuff". I wish there was a local supplier who sold 6" X 12" pieces of FR4.
I am very eager to see just how accurate and consistent the saw is, without handling small pieces. For instance, it would be nice to walk up to the saw and cut (3) - 2.4" X 3.1", and see how they all compare, in measure and squareness. I am fairly certain, they would be very accurate, but like I said, I am not positive.
Oh well, tomorrow is another day.
Any ideas for cheap test material, similar to FR4?
Glad to see your Saw nearly finished.
If you could find some FRP.(Fiber Reinforced Plastic), that might work as a temporary substitute for FR4. It is somewhat similar in how it cuts, a bit softer, but good to practice with.
You can find FRP at Home Cheapo.
I was thinking along those same lines, just haven't got to it yet. However, I must admit that it sounds like a pain, cutting up a 4 X 8 sheet to calibrate a small saw. Accurately aligning the fence is turning out to be a bear. I just wish I had taken the time to accurately center my screw holes for the fence, within the melamine. At the time, I used a punch on the melamine, and just drilled. BIG mistake, but I will get, just as soon as I get more material to work with.
Since I am waiting on materials to finish my extruder, I have decided to start working on my circuit boards.
Several weeks back, I install some FRP in my brothers laundry and of course, I kept all the scraps, so that I could calibrate my saw, without cutting up precious circuit board material. So off and on throughout the day, I have been fiddling with the calibration.
At this point, I am getting pretty close. Considering there are four edges to a normal PCB..... On the width measurements (approximately 2-1/2"), there is approximately a 0.005" discepancy between the two width measurements. On the length measurements (approximately 3-3/8"), there is approximately a 0.006" discepancy between the two length measurements.
Hopefully I will soon have the saw setup just the way I want it, and then, I will soon show you some circuit boards.
As far as I am concerned, the PCB saw is now calibrated, and ready to cut up some serious circuit board material
On a side note pertaining to this project, I still need to purchase the final power supply for this saw and bolt it up, however the battery charger will work just fine until I make the purchase.
Comments
Just a few more things to do:
- Provide a means of securing a spare belt to the cord support column.
- Attach wires to the power posts.
- Cut an initial blade travel path in the table.
- Calibrate saw.
- Provide AC power supply to the saw, however I will operate it on DC until I get the power supply.
Notice the spare blade location on the cord support column.EDIT: Also notice the ample amount of room available under the top for mounting the permanent power supply.
I certainly would not touch the rotating blade, unless of course I wanted to lose a finger.
The spare belt bracket would seem to be a very good 3D print project.
A couple of zip ties would also work.
Very good project.
Thanks for documenting it.
Gary
To hold the spare belt, I will be coming off the 5/8" cord support column with two accurately spaced 1/4" tubes, which will be held in place by (2) 4-40 cap head screws and washers. The washers are larger than the 1/4" tubes and this should retain the belt.
Over the last few days, I have been wondering if this saw would accurately cut my exposure plates. Dremel support told me that the diamond blade cannot be used to cut glass, but I have read online, that some people have cut glass with this blade. Perhaps that is the standard Dremel support answer for that question, due to liability issues and health risks. However, if it can cut glass, that would make my process much easier, and it would not make it anymore dangerous than the current method I have for making accurate plates.
Since I am taking a break, I will briefly discuss these items in the order that I plan to tackle them.
- Calibrating The Saw - Before drilling any holes in my table top, I put a lot of thought into saw calibration. During the fabrication of the shaft mounts, I tried to make them as accurate as possible, but considering the machinery available, needless to say they are not perfect. However, the width of the mounts are identical at the right angle and the drilling for the shafts was based upon this width, and the mounts were positioned according to this width. The problem now becomes aligning the shafts according to the mounts, but hopefully the shaft holes in the mounts will be close enough to allow easy and proper alignment.
- Cut The Blade Notch - Blades will be attached and detached with the saw in the rest position, with the saw assembly pushed to the rearmost travel position. To allow easy attachment and detachment, I will be cutting a 1/8" wide X 7/8" long X 1/16" deep notch into the table top under the blade area. Additionally, this notch will allow me to use the saw to cut the saw travel path within the table top, without disturbing the saw alignment, since the notch will provide a recess below the depth of cut.
- Cut The Saw Travel Path Into The Table Top - Considering I will be powering up the saw for this procedure, I suppose there were only two more items. During this process, I will be applying power to the saw, and cut the initial groove into the top. To help ensure a straight cutting path, I will probably run the path several times, with the saw running, before attempting to cut a PCB.
Any questions?Such an easy phrase to say, but very difficult to achieve
I can easily obtain the full length of travel, but it is not the same smooth fluid motion, like the day after casting the carriage. I am just guessing, but I would say that either the bearings shifted slightly or I slighty bent one of my shafts during the machining process. I think 0.001 - 0.002" additional clearance between the shafts and bearings would do the trick nicely, but I really do not have the means do this accurately.
Most likely, I will mess with it a little more before doing something drastic. If that fails, I would imagine that I will purchase some 1000 and 2000 grit wet or dry sandpaper, and progressively polish the shafts (remove metal
I will keep you posted.
DUH
Many hours down the drain and a lot of frustration. Lesson learned the hard way
Well now that I have that bug figured out, I can start the calibration process all over again
However, please keep in mind the previous lesson, which was, do not bind the shafts by having the mounts too close, because it will distort the shafts and cause grief.
And before I proceed with this discussion, I suppose I should tell you that I have changed my plan a little. Instead of calibrating the saw, I have set my sights on achieving super smooth linear travel, because I want to just gently pull the saw through the material as I cut it.
As it stands now, as determined by math and measurements, the shafts are exactly where they should be and the carriage easily slides the full length of travel, however there is some friction during travel and I want to eliminate this friction. In all honesty, I should have purchased custom linear shafting for this project, but I have lots of shafting from various salvaged printers, and so I used some of that. However, I have had this shafting for many years and I did not properly protect it from damage, so over the years, it has received various nicks, scratches, etc... In addition to that, I now believe the shafts were originally used as rotary shafts, because upon very close inspection, rotary grooves were found on the shaft. These rotary grooves were one of the causes of friction. They were not very deep, so I just polished that area linearly with some 2000 grit sandpaper, meanwhile also removing any other imperfections that I found on the shafts. As a result of this polishing and imperfection removal, the carriage now has a much smoother travel, however I am still tracking down other sources of friction, and I imagine that I will still do some various sanding along the shafts. The 2000 grit sandpaper leaves it's own set of scratches, and I am sure this will also be a source of friction, so when I get very close to the fluid travel that I seek, I will most likely go over the entire shafts with some finer grit sand paper. If I had purchased linear shafting, I am certain the linear travel would areadly be smooth as silk.
Anyhow, I have been protecting the bronze bearings from alterations. These bronze bearings are a lot less forgiving than the UHMWPE that I used on the original saw, but I am certain that I will be much happier with the new saw, once I get the fluid action that I seek.
I suppose that a summary of this post would be that if you can afford linear shafts, just buy them, and if you salvage printer shafting, properly protect it, and last but not least, do not use rotary shafting as linear shafts, or vice versus.
EDITED: Changed 1000 grit to 2000 grit
Although not 100% satisfied with the sliding action, I suppose 95% would best describe it, however I must say that it is pretty darn smooth. I could probably get it to 100%, but that would require removing the shafts from the mounts, and I don't want to risk it at this point. I could also probably make it much better by working on it several more hours, but I believe it is good enough for now. If it becomes a problem, I will deal with it at that point, by either purchasing some linear shafting or by removing the shafts and working on them some more.
Anyhow, while working on the shafts, I came up with a new idea for calibrating the saw. I believe this idea is easier than my last idea for calibration and I believe it should provide a much higher degree of accuracy. ACCURACY.... I know some of you are thinking that accuracy went out the window when I started sanding on the shafts, however this is not true, the shafts still mic out to 0.375", even where I sanded the hardest.
The calibration should now be a quick and easy process, and I also now have a good plan for cutting an accurate blade notch in the table, or at least I think I do
What you should do is obtain a precision cut piece, set the saw, and make a cut. Clamp that down, and make a series of measurements over the length of the cut to understand what your travel actually is.
Having the size of the shaft measure up doesn't necessarily pick up on it being out of square with whatever work stops you've got setup, though that one, if consistent, can be easily compensated for in the stops. It can pick up on out of round sections, but you've got to sample a lot to find those, and they are likely your friction points, so this is improving over time as you sense the motion. (generally)
The big one is non-linear travel, and the length of your bearings does allow for some curvature, and sanding may well improve movement, but increase the curvature and or slop associated with curved portions of travel made easier with the sanding.
Your cut and sample measurements will ferret this out. I would use a minimum of 10 samples per 2-4" of cut board to understand whether or not you've got a curve. Your own repeatability with standard measuring tools is going to be about .002" so take extra samples and curve fit them, if you are wanting to really get down to a few thousandths of overall accuracy. You can do this without a precision piece, if you have a height gauge and calibrated platform.
Edit: If you don't want to curve fit, an alternative to that is to cluster sample and average. At each of the 10 designated points, take a few samples close together and average them.
An alternative, that won't get you absolute kind of accuracy, but will give you some idea of curvature, is to take a piece and perform the same samples and then cut it, then compute the differences using the same fixture and measurement points.
Nice saw so far Bruce!
Thanks for the compliment, however there is a flaw in the design, a complete oversight on my part, and I realized it just as soon as I drilled the holes
Ever since deciding to add the switching power supply, it has been my intention to cover all connections on the underside of the table top, and additionally enclose the connection area of the power supply, with the same enclosure. To make a short story short, I drilled the holes for the table top posts a 1/2" wider than the width of the power supply. Of course this is not a major problem, but it does make the construction of the cover a little more difficult and the overall fit of the cover less appealing.
Hmmmm..... Redo the table top or accept the design flaw? I think I will have to bite the bullet on this one.
@everyone
After taking a break and then getting back to the saw, being the something retentive individual that I am, I decided to rip the shafts back out and polish them well enough to get better action than the previously stated 95%. Although not 100% perfect, because of various nicks, the shafts look pretty darn good at this point and fairly well polished (nice and shiny
I am going back to it now
The carriage now moves a whole lot better. It is still not 100%, but very, very close, and I think I am satisfied at this point.
In additon to reworking the shafts, I have also calibrated the saw, or at least I think I have. It should be very close to perfect, but I will not know for sure, until I start cutting some board material.
So my next step is to cut the blade notch in the table, after which, I can attach the blade, power up the saw, and cut the saw travel path into the table top
While doing the layout for my blade notch, I took one additonal measurement, just to see how square the slide was to the actual table top. At both the start of travel and end of travel, for a total travel of 7-19/64", as measured from the edge of the table to the end of the rotary shaft, there was only a 0.0045" discrepancy. Since the table top is only around 15" deep, that would put me in the ballpark of around 1/128" from front to rear of table. Pretty darn close!
The slide itself, was squared and calibrated according to the fence. So apparently, the fence must be off by a SMIDGE
Guess what time it is. HUMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
Perhaps I got a wee bit excited too soon
The weak link reared it's ugly head. When previously testing the coiled wire and pushbutton switch, I did not have the additional load of the rotary shaft attached to it. I suppose it is needless to say that this wire could not supply the necessary current. I did not melt the wire in two or anything drastic like that, although I am sure I could have, but it simply just did not rotate the motor at a sufficient speed. And of course, the bearings and rotary shaft, needed a slight break in, which did not help matters.
So in the meantime, I wired the motor directly to the battery charger with some 16 gauge wire. When I first fired it up, the RPM was inconsistent, going from high to low and back again. So I started it several times, running it several seconds and shutting it down. And now, it hums with a consistent high RPM.
After the bearing break in, I cut my groove in the table, using the heavy gauge wire. I am happy to say that the saw cut the melamine like a hot knife going through warm butter
Bad news is that I have to find a heavier gauge coiled cable, but in the meantime, the good news is that I can finely tune the saw and cut circuit board material.
Cord problem resolved and the saw is almost completely rewired with the new cord. I will post a couple of new photos tomorrow to show the new cordset.
And tomorrow, I should also be able to run a few accuracy tests, using the measurement procedure that I laid out earlier in the thread. Speaking of which, I decided not to attempt to make the edge of the table exactly 4.00" from the saw kerf. Instead I added about 1/16" to allow for discrepancies.
In addition to mic'ing the test cuts on the sides, I will also be mic'ing the corners and checking squareness with the Pythagorean Theorem.
Here are some new photos for your visual appetite. The new cord does not look as neat and professional as the first cord, but it looks decent enough and it is highly functional. The saw now runs like it was intended to and believe me, it is ready for some serious cutting.
By the way, running the new cord was a real pain.
With my new and extremely easy method of measurement, the new saw cuts highly accurate widths, when cutting from the same edge of the board. However the slide is currently not square to the fence, so cutting from opposite ends, leaves a 0.0045" discrepancy in a 1.25" span, which is no big deal, because I just need to dial it in.
Overall, I am highly please with the operation of the saw and results so far. Just a little more fine tuning, and the arguments can then begin, by those who will dispute my claims of accuracy.
I am very eager to see just how accurate and consistent the saw is, without handling small pieces. For instance, it would be nice to walk up to the saw and cut (3) - 2.4" X 3.1", and see how they all compare, in measure and squareness. I am fairly certain, they would be very accurate, but like I said, I am not positive.
Oh well, tomorrow is another day.
Any ideas for cheap test material, similar to FR4?
If anyone attempts to build the saw as outlined in this thread, do not use self-adhesive vinyl tile as a substitute material for calibrating the saw
It will loosen the blade screw and gum up the blade! Not that I am speaking from experience or that I would ever try anything like that myself
If you could find some FRP.(Fiber Reinforced Plastic), that might work as a temporary substitute for FR4. It is somewhat similar in how it cuts, a bit softer, but good to practice with.
You can find FRP at Home Cheapo.
-Tommy
I was thinking along those same lines, just haven't got to it yet. However, I must admit that it sounds like a pain, cutting up a 4 X 8 sheet to calibrate a small saw. Accurately aligning the fence is turning out to be a bear. I just wish I had taken the time to accurately center my screw holes for the fence, within the melamine. At the time, I used a punch on the melamine, and just drilled. BIG mistake, but I will get, just as soon as I get more material to work with.
Look in the Cabinet Department, There will be some small samples of Formica that you can sample too. :thumb:
-Tommy
Several weeks back, I install some FRP in my brothers laundry and of course, I kept all the scraps, so that I could calibrate my saw, without cutting up precious circuit board material. So off and on throughout the day, I have been fiddling with the calibration.
At this point, I am getting pretty close. Considering there are four edges to a normal PCB..... On the width measurements (approximately 2-1/2"), there is approximately a 0.005" discepancy between the two width measurements. On the length measurements (approximately 3-3/8"), there is approximately a 0.006" discepancy between the two length measurements.
Hopefully I will soon have the saw setup just the way I want it, and then, I will soon show you some circuit boards.
RESULTS:
Edge B: 2.047"
Edge C: 4.564"
Edge
On a side note pertaining to this project, I still need to purchase the final power supply for this saw and bolt it up, however the battery charger will work just fine until I make the purchase.