As it turns out, the oil was just on the surface of the JB Weld and probably seeped out of the bearing. I wiped it down with laquer thinner last night and it has not returned.
In addition to lengthening the angle aluminum to prevent dust from getting into the motor, I am now adding a piece of channel to encapsulate most of the blade area for safety and better dust control. Although not shown in the illustration below, this dust/safety shield will be attached to the rotary shaft housing with two screws.
Additionally, I will probably be altering the handle bracket to include the on/off switch.
One other item that is worth mentioning.... If I had known ahead of time that I was going to redesign the whole saw and if I had known that it would end up being assembled as shown, I would have cast both the linear bearings and the rotary bearings into one solid casting.
At this point, I am really wishing I had cast the rotary shaft bearings at the same time as the linear shaft bearings.
After making my blank for the rotary shaft housing, I drilled it out to accept the bearings. During this process, the drill bit walked a little from top to bottom, which of course will throw the blade out of alignment. As I see it, the shaft will be approximately one degree out of horizontal alignment. This one degree should cause the blade to be slightly angled, equating to approximately 0.008" between the top of the cut and the bottom of the cut, on a 1/16" thick PCB. If both sides of a PCB were to be cut, it would total about 1/64" difference from the top of the board to the bottom.
As it stands, I am not certain what I am going to do just yet. I may try milling it to be true or I may just let it go and see how it works with my process.
The photos below represent my feable attempt to satisfy prof_braino's request for photos, without causing myself too much additional work.
One of the photos represent the setup prior to cast, however the bottom of the mold was parallel to the top of the cutting surface and the linear shafts were spaced equally from the side walls of the mold.
The additional photos show the outcome of the cast and various parts of the project.
Photos of the previous PCB saw will be included in my next post.
As mentioned in the previous post, I do not want to cause myself too much additional work, just for a photo request.
In the photos below you will see most of the compents which made up the previous PCB saw, before I destroyed it Since then, the table has been chopped up and various parts have been scavenged.
As if the misdrilled rotary shaft housing wasn't bad enough....
I just discovered that the angle aluminum that I purchased for the motor mount is approximately 1/16 of inch out of square along a 3" run, and in my opinion, that is pretty bad. I cannot believe the things people sell today with a clean conscience.
For such a simple design, things are getting complicated for a makeshift workshop. Do I bend or do I mill the angle? That is the question (not really wanting an answer )
Milling the rotary shaft housing was a bit of challenge, but I am happy to say that it is now in excellent condition and ready to spin that diamond blade plumb and square to the table top. Additionally, the angle aluminum for the motor mount is now also square, after several whacks with a large rubber mallet.
I am hoping that all major obstacles have been eliminated and that I can move along with finishing my new design of the saw. By all indications, it appears that it should be smooth sailing from this point. However, I am also going to cut my linear shafts to reduce the travel and I always hate drilling shafts, because the holes need to be smack dead center for easy alignment.
Hopefully by tomorrow, I can start making the new table top.
Besides being tempermental, the previous saw was highly accurate, although some doubted my claims. In all fairness, it was difficult to set the saw up for highly accurate cuts. In fact, I considered it drudgery, and it was probably the single most and hated chore of making PCBs. If I had taken the time to think it through, I am certain that I could have simplified this process immensely.
As I go forth in making my new version of the PCB saw, I keep thinking about accuracy and measurement. Beyond any doubt, a secure stop block is a prerequiste for making accurate cuts. Without going out and buying a depth guage, over the last few days, I have been thinking about various ways of adapting the my dial calipers to the saw, for accurately placing the stop block. I do not have it all figured out, but just sharing my thoughts, so you folks know where I am headed.
In other words, I am taking a break A little R & R
I do double exposures, with an exposure frame, simultaneously, so for one, the PCB must fit the frame tightly to prevent stray light. I have also had problems with light creepage when the PCB did not fit the frame tightly. Instead of relying on vacuum to hold the positive or negative flat, I rely on the pressure of very tight fits. In order of placement:
Glass
Positive Film
PCB
Positive Film
Glass
Items 2, 3, 4, and 5, must all fit within the perimeter of the frame.
Additionally, even though I have not made my PCB driller yet, I still intend to. To accurately achieve drilling, at least one corner should be perfectly square and run true for the length and width of the board.
How are you insuring your exposures are aligned to that precision?
It is all based upon the perimeter of a square or a rectangle, either it fits or it doesn't, and if it does fit, is there any noticable slop. Alignment of the films can be checked by placing the top and bottom film within the exposure frame and turing the light on.
Does everything line up?
Can the films be moved to cause misalignment?
In that case, why not over cut the board, and use the frame contact with the board, on it's larger exposure surface instead of the edge surface, to prevent light pollution between the sides?
In reality it is more of a board alignment issue than a stray light issue. And in all honesty, it is really not that big of a deal at the moment, because I have not finished the PCB driller. For both hand and automated drilling, the films must be aligned with no slop. For hand drilling, the PCB does not have to be a perfect fit, however the board turns out much nicer if it is. For automated drilling, both the films and the PCB must be tight for alignment purposes.
There is always slop. The question is how much, and how you establish datums to work from. Standard registration marks can yield alignments on the order of .003 or so for average sized boards we discuss in here. That's underneath or perhaps on par with the precision of everything you've discussed so far.
Interestingly, when doing design, the nominal dimension is the only one you can never get. Keep that in mind, and tolerances make a lot of sense! Great rule, works for me!
Frankly, you've got conflicting constraints and goals. The conflicting constraint is the need for alignment coupled with a frame requiring fit on all sides. You've indicated no need for the overall board size to be manufactured to the precision your frame requires, in addition.
All requirements could be met to the precision you are looking for, by working off one corner of the board, and with registration marks for the exposure films. The key to this is one datum; namely, a corner of the board, and it's edges. It's possible to build the films to that and keep the board fairly precise if you want, but it could be over cut too. Wouldn't matter, as the films contain the marks needed to align to the board corner.
When it comes to the driller, that program could also be made from the same datum, and could make use of the same registration marks, if you choose to leave them on the board. Otherwise, it can use the edges. A simple fixture and caliper measurements can get the board true to the drilling program for reasonable board sizes as the ~.002 or so accuracy of those will work just fine.
I was asking because I really didn't see how an all around fit improves things any.
I was asking because I really didn't see how an all around fit improves things any.
Theoretically, it doesn't do anything, providing you can align the bottom film, the PCB, and the top film without messing up the alignment, and I would imagine that when working with a size of 6 X 6 or so, alignment is much easier to accomplish, especially with multi-board exposures. However lets assume the do-it-yourselfer (me), exposing a 2 X 2, without wasting expensive material. Your example would be very difficult to accomplish well, or even smaller, a 1 X 1. Good luck with that one.
What is the material cost of the adventures so far?
Costs are inclusive, right? So you've incurred them anyway.
That smaller board could very easily have been done from a larger bit of stock. Cut to size when complete. And then you are making stuff, not making stuff to make stuff.
Just tossing some thoughts out there. Things appear much harder than they need to be.
For those that may be interested in my progress, I will be working on the motor mount today. When the motor mount is finished, which should be sometime later today, I will then be able to drill out the carriage and rotary shaft housing for the two screws which join the main parts together. Additionally, I will also be ordering my timing belt, and I already have the pulleys.
After today, the only main part left to fabricate for the cutter assembly, will be the rotary shaft, and most likely I will work on that tomorrow. It won't be long until I have a new running PCB cutter.
My system and way of doing things was working well until I destroyed my cutter. I have tried other routes, which is why I developed this way of doing things. Unless I get careless, and then it is my own darn fault for the screw up.
If I thought there was a better way, don't you think I would be doing it the supposedly better way? People have been using exposure frames for a very long time, and the concept of using a frame for photography is nothing new.
People can bash me all they want, because I know what I have and what it is capable of.
It's not an issue of "bashing". It's just that using a frame for alignment has its limitations and people have used all sorts of techniques to improve the accuracy of alignment / registration of multiple layers including the use of optical registration marks in all layers, machined pins with matching holes in each layer, etc. depending on the materials involved and the accuracy needed.
Perhaps "bash me" was the wrong phrase to use, but is was implied the my methods were inferior. For a do-it-yourselfer, I have a very sweet setup and it works well enough for me, unless I do something stupid.
There are many times that I want and need help, but exposing PCBs is not one of them. In the time that I have been here, it seems to me that most folks have a very negative attitude to making you're own PCBs. I could state my own beliefs for these attitudes, but I will keep them to myself. For the most part, it has either been that I am wasting my time or that I am doing it wrong.
The discussion evolved from trying a new idea that worked out superbly, to obtaining the best accuracy that I can from the new saw that I am building. Regardless of the end goal, the discussion shifted to accuracy. If anyone has ideas about how to incorporate dial calipers into a PCB saw with a stop block, then I am all ears and I want and need help.
For what it's worth, I offered the experiences I did with the intent of giving you some food for thought regarding accuracy, which we've discussed a time or two before. Your methods are your methods. When you share things here, people are going to have thoughts and share them. You, of course, can take those how you will, but the intent is generally to share the thoughts in the hopes your project efforts see the benefit. Often, a dialog like that will shake out some good thoughts, which is why we do what we do here.
If that's seen as a "slam", perhaps it's unwise to read and think about what you put here. See how that works?
Regarding the dial calipers, I've often used the end away from the forks for this purpose. If you extend them some, you will see the slider protrude beyond the body of the caliper. That slider has a nice, flat machined end that is ideal for locating a stop. The technique is to mount a shelf somewhere that you can place the body of the caliper against. Use the flat, end edge where the slider comes out of.
Dial your desired distance and lock the caliper with the knob at top, near the indicator. Now, you've got a distance stop. Hold the caliper body against the shelf, or flange surface and dial your stop, until it contacts the machined end of the caliper slide. You can visually see the caliper body move away from it's resting position, when you've come in too close. Apply gentle pressure to the caliper body, while dialing, or manually adjusting your stop, until you've brought the stop to the desired position. This takes a bit of practice, but you will find you can feel the caliper move, and then "stop" as you adjust the saw stop. Once you've got that feel, it's possible to repeat stop positions within .005" or so consistently.
If you need more, machine a small hole in your backstop such that you can insert the caliper slide and use a screw to latch onto it. You can adjust the dial position to account for the little bit of slide you engage inside the backstop, allowing for a direct reading. Say you've engaged .230" of the caliper slide. No worries. Adjust the dial .030", then simply subtract the .2 mentally as you read the dial.
Clamp the caliper body on it's primary fork, and now you've got an indicator. Move the stop as needed, reading the dial. If you need to repurpose the caliper, unset the stop screw and remove the clamp, and your dial calipers are unchanged. (assuming moderate forces are in play the whole time) When you want to use them again, re-clamp, re-set the slide, and make a quick dial adjustment. A block of some known size can be placed between the saw blade and the stop to calibrate the dial indicator quickly.
Measure your saw blade and add .002" or so to allow for variances in the kerf, and you will have a fairly high precision saw with stop.
All that said, I really don't recommend using dial calipers that way, but it works really well! Often, Harbor Freight has digital ones with very reasonable precision and repeatability for $10 - $20 or so. Recommended for this kind of thing.
Regarding the dial calipers, I've often used the end away from the forks for this purpose. If you extend them some, you will see the slider protrude beyond the body of the caliper. That slider has a nice, flat machined end that is ideal for locating a stop. The technique is to mount a shelf somewhere that you can place the body of the caliper against. Use the flat, end edge where the slider comes out of.
Dial your desired distance and lock the caliper with the knob at top, near the indicator. Now, you've got a distance stop. Hold the caliper body against the shelf, or flange surface and dial your stop, until it contacts the machined end of the caliper slide. You can visually see the caliper body move away from it's resting position, when you've come in too close. Apply gentle pressure to the caliper body, while dialing, or manually adjusting your stop, until you've brought the stop to the desired position. This takes a bit of practice, but you will find you can feel the caliper move, and then "stop" as you adjust the saw stop. Once you've got that feel, it's possible to repeat stop positions within .005" or so consistently.
If you need more, machine a small hole in your backstop such that you can insert the caliper slide and use a screw to latch onto it. You can adjust the dial position to account for the little bit of slide you engage inside the backstop, allowing for a direct reading. Say you've engaged .230" of the caliper slide. No worries. Adjust the dial .030", then simply subtract the .2 mentally as you read the dial.
Clamp the caliper body on it's primary fork, and now you've got an indicator. Move the stop as needed, reading the dial. If you need to repurpose the caliper, unset the stop screw and remove the clamp, and your dial calipers are unchanged. (assuming moderate forces are in play the whole time) When you want to use them again, re-clamp, re-set the slide, and make a quick dial adjustment. A block of some known size can be placed between the saw blade and the stop to calibrate the dial indicator quickly.
Measure your saw blade and add .002" or so to allow for variances in the kerf, and you will have a fairly high precision saw with stop.
All that said, I really don't recommend using dial calipers that way, but it works really well! Often, Harbor Freight has digital ones with very reasonable precision and repeatability for $10 - $20 or so. Recommended for this kind of thing.
Now that is exactly what I want and needed, input for the direction I am heading. Thank you for that potatohead. I will print that out and see if I can set it up exactly the way that you so nicely described. In fact, that sounds like some nice knowledge that you shared.
I agree that it is all about sharing knowledge, both good and bad.
This is my Z axis for a PCB driller, made from 1/8 X 2 X 2 6063-T52 aluminum square tubing.
Even though I made some good progress with the saw, I was hoping to be further along then I am at this point.
Since changing the configuration of the saw, I no longer have a good place to put my power switch, especially since I want one hand on the PCB material and the other on the saw handle. On the old saw, it was simply a flick of the index finger of the hand on the handle, but with the new saw configuration, there is no way to mount the switch that is aesthetically pleasing to me. At this point, the assembly is looking very nice and I do not want to screw it up, with poor switch placement.
This morning I was doing a little investigation into capacitive switches. Considering that the saw assembly is electrically isolated due to the JB Weld, I suppose theoretically it is possible to touch the metal part of the handle to start the saw, but I am uncertain how the motor would affect the circuitry, and then of course, the design becomes more complicated.
As I was typing the last paragraph, I came up with a new idea. On the old saw, the knob (handle) was secured to the saw with a solid steel rod. If I replace the solid steel rod, with some aluminum tubing, I could drill out the knob for a pushbutton switch and route my wires through the tubing. The middle and index finger could go behind the knob for pulling action, and the thumb could be used to activate the switch.
Hi
Have you given any thought to a foot operated switch?
It might be your best bet.
Switch placement troubles would become the, where do I put the cable.
Just a thought.
And
What is the approximate distance of your drill machine Z axis drill bit to column?
Just wondering, as that would determine the max size of the circuit board you wish to drill.
Here I am talking about aesthetics, when I use a battery charger to run the motor. The DeWalt motor requires a bit of JUICE, so instead of building a power supply especially for the saw, I simply set the charger to 50 Amps START and plug her in
The previous setup was a bit more complex than what I will be attempting this time. This time around, I will simply have a positive and negative post on the saw for connecting the charger. It got to be a pain with extra cables for this or that.
As for the Z-axis, all of my PCB equipment is setup for a maximum board size of 3" X 4" (actually I can go a little larger, but not much). The distance from the drill bit to the column is currently 4-3/8", however that is easily changed, by replacing the connecting arm.
Here are some progress photos for your viewing pleasure.
As mentioned earlier, I was hoping to be a little further along by now, but it will take as long as as it it takes However, it should really be shaping up by the end of the day.
Notice the momentary pushbutton set inside the knob. I doubt it will hold up due to the rating, but I am going to try it anyhow. If it fails, it won't be any great loss of time or materials.
Well... I had another drill bit take a walk on me while drilling a 45 degree angle for the handle. Of course I was trying a new technique that failed miserably.
I should have gone with the tried and true method of milling a flat spot before drilling. Live and learn.
Oh well, it is only off by a little bit and it is not a part that is crucial to the operation of the saw. I will finish it up and see what it looks like. Let me know if you can tell, when I post a new pic.
Comments
As it turns out, the oil was just on the surface of the JB Weld and probably seeped out of the bearing. I wiped it down with laquer thinner last night and it has not returned.
In addition to lengthening the angle aluminum to prevent dust from getting into the motor, I am now adding a piece of channel to encapsulate most of the blade area for safety and better dust control. Although not shown in the illustration below, this dust/safety shield will be attached to the rotary shaft housing with two screws.
Additionally, I will probably be altering the handle bracket to include the on/off switch.
One other item that is worth mentioning.... If I had known ahead of time that I was going to redesign the whole saw and if I had known that it would end up being assembled as shown, I would have cast both the linear bearings and the rotary bearings into one solid casting.
At this point, I am really wishing I had cast the rotary shaft bearings at the same time as the linear shaft bearings.
After making my blank for the rotary shaft housing, I drilled it out to accept the bearings. During this process, the drill bit walked a little from top to bottom, which of course will throw the blade out of alignment. As I see it, the shaft will be approximately one degree out of horizontal alignment. This one degree should cause the blade to be slightly angled, equating to approximately 0.008" between the top of the cut and the bottom of the cut, on a 1/16" thick PCB. If both sides of a PCB were to be cut, it would total about 1/64" difference from the top of the board to the bottom.
As it stands, I am not certain what I am going to do just yet. I may try milling it to be true or I may just let it go and see how it works with my process.
One of the photos represent the setup prior to cast, however the bottom of the mold was parallel to the top of the cutting surface and the linear shafts were spaced equally from the side walls of the mold.
The additional photos show the outcome of the cast and various parts of the project.
Photos of the previous PCB saw will be included in my next post.
In the photos below you will see most of the compents which made up the previous PCB saw, before I destroyed it
I just discovered that the angle aluminum that I purchased for the motor mount is approximately 1/16 of inch out of square along a 3" run, and in my opinion, that is pretty bad. I cannot believe the things people sell today with a clean conscience.
For such a simple design, things are getting complicated for a makeshift workshop. Do I bend or do I mill the angle? That is the question (not really wanting an answer
Milling the rotary shaft housing was a bit of challenge, but I am happy to say that it is now in excellent condition and ready to spin that diamond blade plumb and square to the table top. Additionally, the angle aluminum for the motor mount is now also square, after several whacks with a large rubber mallet.
I am hoping that all major obstacles have been eliminated and that I can move along with finishing my new design of the saw. By all indications, it appears that it should be smooth sailing from this point. However, I am also going to cut my linear shafts to reduce the travel and I always hate drilling shafts, because the holes need to be smack dead center for easy alignment.
Hopefully by tomorrow, I can start making the new table top.
As I go forth in making my new version of the PCB saw, I keep thinking about accuracy and measurement. Beyond any doubt, a secure stop block is a prerequiste for making accurate cuts. Without going out and buying a depth guage, over the last few days, I have been thinking about various ways of adapting the my dial calipers to the saw, for accurately placing the stop block. I do not have it all figured out, but just sharing my thoughts, so you folks know where I am headed.
In other words, I am taking a break
Plain old eye hand coordination, some measurements, marks and a steady hand can yield +- .050 or so, often better.
If you do this right, you could get +-.007" Maybe +-.010"
FWIW, a skilled user of dial calipers is generally repeatable to about .002" For each mechanical interface to your stop, add .001 to .002"
That puts your saw at about .015" overall, just from what I see here.
What warrants that precision?
I do double exposures, with an exposure frame, simultaneously, so for one, the PCB must fit the frame tightly to prevent stray light. I have also had problems with light creepage when the PCB did not fit the frame tightly. Instead of relying on vacuum to hold the positive or negative flat, I rely on the pressure of very tight fits. In order of placement:
- Glass
- Positive Film
- PCB
- Positive Film
- Glass
Items 2, 3, 4, and 5, must all fit within the perimeter of the frame.Additionally, even though I have not made my PCB driller yet, I still intend to. To accurately achieve drilling, at least one corner should be perfectly square and run true for the length and width of the board.
It is all based upon the perimeter of a square or a rectangle, either it fits or it doesn't, and if it does fit, is there any noticable slop. Alignment of the films can be checked by placing the top and bottom film within the exposure frame and turing the light on.
Does everything line up?
Can the films be moved to cause misalignment?
There is always slop. The question is how much, and how you establish datums to work from. Standard registration marks can yield alignments on the order of .003 or so for average sized boards we discuss in here. That's underneath or perhaps on par with the precision of everything you've discussed so far.
Interestingly, when doing design, the nominal dimension is the only one you can never get. Keep that in mind, and tolerances make a lot of sense! Great rule, works for me!
Frankly, you've got conflicting constraints and goals. The conflicting constraint is the need for alignment coupled with a frame requiring fit on all sides. You've indicated no need for the overall board size to be manufactured to the precision your frame requires, in addition.
All requirements could be met to the precision you are looking for, by working off one corner of the board, and with registration marks for the exposure films. The key to this is one datum; namely, a corner of the board, and it's edges. It's possible to build the films to that and keep the board fairly precise if you want, but it could be over cut too. Wouldn't matter, as the films contain the marks needed to align to the board corner.
When it comes to the driller, that program could also be made from the same datum, and could make use of the same registration marks, if you choose to leave them on the board. Otherwise, it can use the edges. A simple fixture and caliper measurements can get the board true to the drilling program for reasonable board sizes as the ~.002 or so accuracy of those will work just fine.
I was asking because I really didn't see how an all around fit improves things any.
Have fun! I'll leave you to it.
Theoretically, it doesn't do anything, providing you can align the bottom film, the PCB, and the top film without messing up the alignment, and I would imagine that when working with a size of 6 X 6 or so, alignment is much easier to accomplish, especially with multi-board exposures. However lets assume the do-it-yourselfer (me), exposing a 2 X 2, without wasting expensive material. Your example would be very difficult to accomplish well, or even smaller, a 1 X 1. Good luck with that one.
Costs are inclusive, right? So you've incurred them anyway.
That smaller board could very easily have been done from a larger bit of stock. Cut to size when complete. And then you are making stuff, not making stuff to make stuff.
Just tossing some thoughts out there. Things appear much harder than they need to be.
After today, the only main part left to fabricate for the cutter assembly, will be the rotary shaft, and most likely I will work on that tomorrow. It won't be long until I have a new running PCB cutter.
My system and way of doing things was working well until I destroyed my cutter. I have tried other routes, which is why I developed this way of doing things. Unless I get careless, and then it is my own darn fault for the screw up.
If I thought there was a better way, don't you think I would be doing it the supposedly better way? People have been using exposure frames for a very long time, and the concept of using a frame for photography is nothing new.
People can bash me all they want, because I know what I have and what it is capable of.
Good luck. Hope it works out well.
Perhaps "bash me" was the wrong phrase to use, but is was implied the my methods were inferior. For a do-it-yourselfer, I have a very sweet setup and it works well enough for me, unless I do something stupid.
There are many times that I want and need help, but exposing PCBs is not one of them. In the time that I have been here, it seems to me that most folks have a very negative attitude to making you're own PCBs. I could state my own beliefs for these attitudes, but I will keep them to myself. For the most part, it has either been that I am wasting my time or that I am doing it wrong.
The discussion evolved from trying a new idea that worked out superbly, to obtaining the best accuracy that I can from the new saw that I am building. Regardless of the end goal, the discussion shifted to accuracy. If anyone has ideas about how to incorporate dial calipers into a PCB saw with a stop block, then I am all ears and I want and need help.
If that's seen as a "slam", perhaps it's unwise to read and think about what you put here. See how that works?
Regarding the dial calipers, I've often used the end away from the forks for this purpose. If you extend them some, you will see the slider protrude beyond the body of the caliper. That slider has a nice, flat machined end that is ideal for locating a stop. The technique is to mount a shelf somewhere that you can place the body of the caliper against. Use the flat, end edge where the slider comes out of.
Dial your desired distance and lock the caliper with the knob at top, near the indicator. Now, you've got a distance stop. Hold the caliper body against the shelf, or flange surface and dial your stop, until it contacts the machined end of the caliper slide. You can visually see the caliper body move away from it's resting position, when you've come in too close. Apply gentle pressure to the caliper body, while dialing, or manually adjusting your stop, until you've brought the stop to the desired position. This takes a bit of practice, but you will find you can feel the caliper move, and then "stop" as you adjust the saw stop. Once you've got that feel, it's possible to repeat stop positions within .005" or so consistently.
If you need more, machine a small hole in your backstop such that you can insert the caliper slide and use a screw to latch onto it. You can adjust the dial position to account for the little bit of slide you engage inside the backstop, allowing for a direct reading. Say you've engaged .230" of the caliper slide. No worries. Adjust the dial .030", then simply subtract the .2 mentally as you read the dial.
Clamp the caliper body on it's primary fork, and now you've got an indicator. Move the stop as needed, reading the dial. If you need to repurpose the caliper, unset the stop screw and remove the clamp, and your dial calipers are unchanged. (assuming moderate forces are in play the whole time) When you want to use them again, re-clamp, re-set the slide, and make a quick dial adjustment. A block of some known size can be placed between the saw blade and the stop to calibrate the dial indicator quickly.
Measure your saw blade and add .002" or so to allow for variances in the kerf, and you will have a fairly high precision saw with stop.
All that said, I really don't recommend using dial calipers that way, but it works really well! Often, Harbor Freight has digital ones with very reasonable precision and repeatability for $10 - $20 or so. Recommended for this kind of thing.
Now that is exactly what I want and needed, input for the direction I am heading. Thank you for that potatohead. I will print that out and see if I can set it up exactly the way that you so nicely described. In fact, that sounds like some nice knowledge that you shared.
I agree that it is all about sharing knowledge, both good and bad.
This is my Z axis for a PCB driller, made from 1/8 X 2 X 2 6063-T52 aluminum square tubing.
Thanks potatohead
Since changing the configuration of the saw, I no longer have a good place to put my power switch, especially since I want one hand on the PCB material and the other on the saw handle. On the old saw, it was simply a flick of the index finger of the hand on the handle, but with the new saw configuration, there is no way to mount the switch that is aesthetically pleasing to me. At this point, the assembly is looking very nice and I do not want to screw it up, with poor switch placement.
This morning I was doing a little investigation into capacitive switches. Considering that the saw assembly is electrically isolated due to the JB Weld, I suppose theoretically it is possible to touch the metal part of the handle to start the saw, but I am uncertain how the motor would affect the circuitry, and then of course, the design becomes more complicated.
As I was typing the last paragraph, I came up with a new idea. On the old saw, the knob (handle) was secured to the saw with a solid steel rod. If I replace the solid steel rod, with some aluminum tubing, I could drill out the knob for a pushbutton switch and route my wires through the tubing. The middle and index finger could go behind the knob for pulling action, and the thumb could be used to activate the switch.
That just might work.
HMMMMM.....
I will let you know.
Have you given any thought to a foot operated switch?
It might be your best bet.
Switch placement troubles would become the, where do I put the cable.
Just a thought.
And
What is the approximate distance of your drill machine Z axis drill bit to column?
Just wondering, as that would determine the max size of the circuit board you wish to drill.
Here I am talking about aesthetics, when I use a battery charger to run the motor.
The previous setup was a bit more complex than what I will be attempting this time. This time around, I will simply have a positive and negative post on the saw for connecting the charger. It got to be a pain with extra cables for this or that.
As for the Z-axis, all of my PCB equipment is setup for a maximum board size of 3" X 4" (actually I can go a little larger, but not much). The distance from the drill bit to the column is currently 4-3/8", however that is easily changed, by replacing the connecting arm.
As mentioned earlier, I was hoping to be a little further along by now, but it will take as long as as it it takes
Notice the momentary pushbutton set inside the knob. I doubt it will hold up due to the rating, but I am going to try it anyhow. If it fails, it won't be any great loss of time or materials.
I should have gone with the tried and true method of milling a flat spot before drilling. Live and learn.
Oh well, it is only off by a little bit and it is not a part that is crucial to the operation of the saw. I will finish it up and see what it looks like. Let me know if you can tell, when I post a new pic.
ARG :frown: