JR's Solsylva 25x37 Router Build

[Tayloned]

Hello to all CNCZone menbers....

An absolute novice here, attempting to build first cnc router.

Recently bought David Steels' plan book and decided to build the 25" x 37" table as per plan but with a few minor modifications. Being in the UK the plans had to converted to metric. Hence, the following thread sizes were to be used; M8 for the lead screws, M6 for the tie rods, M5, M4 for the No.10 UNC and No.8 UNC, respectively. What really confused me with the plans was that the sizes stated in the material list were not those actually used. The sizes stated were the rough sawn sizes, NOT the finished planed sized actually used! Not best practice here in the UK!

1) Decide to use well seasoned Beech for all the wooden parts.
2) Make my own all-thread coupler from brass.
3) Use Stainless steel 304 grade tubing for the rails
4) Use stainless A2 grade all-thread rod.
5) Build own driver boards as per Aaron Gargber's design for steppers of up to 3A per phase.

Any comments as to the materials and minor mods?

Kindest regards, John R.

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[CarveOne]

Welcome John R.,

Here in the US the lumber sizes are standardized, but just not the standard dimension that is marked. A 1 x 4 is really 3/4" x 3-1/2". But even that varies 1/8" due to the high speed way that construction lumber is milled.

I'm using premium cabinet grade clear red oak that is square edged (not rounded) and is dimensionally very accurate. We can buy similar boards of poplar that is lower cost than the red oak. Oak is stiffer and looks better.

David's plans have no errors that I have found. Some of the upgrades like 1/2" lead screws will require you to make the shaft holes larger or possibly shift the position of the shaft hole slightly if you use anti-backlash nuts.

One easy no cost upgrade is to make the end plate that the x axis stepper mounts on double thickness (same as the side rails) when you are making parts for the frame. Use correspondingly longer bolts for the stepper and idler. A 1x4 board flexes too much.

Check the other Solsylva 25x37 build logs here for some ideas. If you have questions, just ask.

CarveOne

[Tayloned]

CarveOne,

Thank you for your comments and I take note about the flexing of the endplates. Will modify the endplate and screw and glue a section of timber to the underside of the stepper motor endplate to form a tee section endplate to strenghten and minimise any twisting action. Probably structurally better than just thickening up the endplate section.

Plus may have found a dimensional error with the z-axis alignment of the stepper plate with the top plate z axis. There appears to be 0.45mm dimensional mis-alignment. Have emailed David Steele requesting confirmation. I'll await his answer...

Kindest regards, John R.

[CarveOne]

Tayloned,

I considered cutting to length and splitting a 1x4 board down the middle and then gluing the two strips edgewise to the inside top and bottom of the end plate to form a "C" channel. That would allow the original bolt lengths to remain but I would have to cut notches in the lower strip to clear the lowest carriage bolt head, which then wouldn't be removeable if ever needed. I decided to just double the thickness and get some 4" carriage bolts. Doing this has removed almost all of the flexing. To test for flexing I'm just holding the stepper motor in my hand and using it as a lever to see how much force is required to see any movement of the end plate. I was surprised at how easy it was to bend the red oak end plate before adding the end plate doubler board. rc_flyer suggested that I do this change. He has been using one of these 25x37 cnc router machines in his R/C model kit cutting business for a year and has recently made a number of upgrades to his machine. I'm making similar upgrades as I build my first cnc machine. Check my CarveOne build log for more info.

CarveOne

[Regnar]

Just a suggestion but you could build the 13x13 one and use it make the bigger one. It would allow you to make almost everything except for the long rails and also get your feet wet before jumping into something big. Just buy the electronics and motor for the bigger one and use them on the smaller one until you switch over. The website says less than 100usd to build. If I could have done it all over again that is the route that I would have gone.

[Tayloned]

Welcome Regnar and CarveOne

Thank you Regnar for your advice and your voice of experience, but a little too late as I've ordered the wood and other items for the larger table. However a very good thought. Use to jumping in at the 'deep end'.....


Also thank you CarveOne for your comments on stengthening the endplates, and I note your additional remarks and experience.

Kindest regards, John R.

[Tayloned]

Just an update.....

Ordered the following items from the UK in preparation to building the 25" x 37" table:

1) All the aluminium material from Droitwich Aluminium, and was cut to size, accurately FOC. Great help!
2) Skate bearings (ABEC 7) from VXB via Ebay
3) All the Beech wood blanks from Woodstock of Telford
4) All the stainless steel tubing grade 304 in direct replacement for the EMT tubing as stated in the plan from another ebay supplier. The tubing was cut to length FOC. Tubing OD was 26mm and 21mm for the 3/4" & 1/2" EMT respectively.
5) All the nuts/bolts/washers from Coronhust of Cannock
6) The pulleys and belts from SDP as reccomended in the plans.
7) Yet to get the 3/4" MDF for the table base from a local DIY store.
8) The stainless steel M8 & M6 all-thread rods via a supplier on Ebay.
9)The stepper motors from an Ebay supplier.
10) Stepper motor driver kits from Aaron Garber in the states.

So good to go soon and look forward to having time to play...... Will post some photos soon when there is something worth viewing.

Kindest regards, John R.

[Tayloned]

CarveOne,

In your build have you experienced the Ali-Channel sides distorting when tightening the clamp bolts? If this is the case then the channel is acting like a spring and is not really stiff enough to support the EMT tubing without bending or flexing of the tubing. May be the cause of some lockups that other members have reported here. What is your experience?

Kindest regards, John R.

[Tayloned]

Aaron's Stepper motor programmable driver boards kits arrived and have now been assembled. Plus an enclosure of own design has been constructed to house 3 of these boards. The aluminium plates used also act as an extended heatsinks for the driver chips used. Photos attached...

Also can provide technical drawings of parts, if anyone is interested...

[CarveOne]

CarveOne,

In your build have you experienced the Ali-Channel sides distorting when tightening the clamp bolts? If this is the case then the channel is acting like a spring and is not really stiff enough to support the EMT tubing without bending or flexing of the tubing. May be the cause of some lockups that other members have reported here. What is your experience?

Kindest regards, John R.

Yes, that is what I have heard was happening, but not with my build. I cut some wood strips that fill the channel between the bolts and is just thick enough to prevent the over tightening issue. If I feel it tighten against something hard I know it's about the correct tightness.

CarveOne

[CarveOne]

Aaron's Stepper motor programmable driver boards kits arrived and have now been assembled. Plus an enclosure of own design has been constructed to house 3 of these boards. The aluminium plates used also act as an extended heatsinks for the driver chips used. Photos attached...

Also can provide technical drawings of parts, if anyone is interested...

That's a very robust enclosure, and well made. Nice job on the design.

Edit: I just noticed that the small on-board heat sink is 90 degrees to the flow of air. Could you rotate the boards so that the heat sink is in line with the flow of air for less air restriction?

CarveOne

[Tayloned]

CarveOne,

Many thanks for your comments and have noted your experience with regard to the Ali-channels flexing. The small heatsinks in the enclosure cannot be turned around but airflow holes and slot have been made to inprove airflow, that cannot be seen in the photos. Those 40mm fans push a vast amount of air over all the boards and the enclosure does have a top and bottom plate to form air channels for each board.

Kindest regards, John R.

[CarveOne]

Ok, good. By the time that all cable connectors are installed on the board there didn't seem to be a lot of space left for the air flow, and that may slow the fans down due to the space restrictions. It's all a careful balance for acceptable cooling anyway. If it became necessary, you could machine some length wise channels in the divider plates to help improve air flow or try flipping the fans so that they pull versus push air.

CarveOne

[Tayloned]

Now all the ordered material has arrived, will start making the bits and posting some photos of the work in progress. Have noted that the M8 carriage bolts have a head diameter of 20mm and hence are larger than the ones specified in the plan. May cause some problems with the counterboring required.

Also, had confirmed from David Steele that the Z-axis dimensions on his plans are inaccurate and there is a dimensional mis-alignment of 0.45mm. The co-ordinate maths just does not add up correctly. On checking the gantry stepper motor plate the same type of error is apparent. To overcome problem see suggestion below.

SUGGESTION:

1)Drill the stepper motor mounting holes in the main wood section as specified but using a drill size equal to the diameter of the carriage bolts, and drill the bearing centre hole the diameter of the stepper motor shaft.
2) Make the stepper motor plates but DO NOT drill the mounting holes for the carriage bolts.
3) Bolt the stepper motor to the plate and position stepper motor shaft in bearing hole.
4) Clamp stepper mounting plate in its correct position and drill the plate using the holes in the main wood section as a template.
5) Now drill out the bearing hole as specified.

Then you should have all holes correctly aligned without any further adjustment being necessary.

[CarveOne]

John,

You could reduce the carriage bolt head diameters to fit by turning them in a lathe or filing them down in a drill press. Spray paint the heads silver if you don't care for the eventual rust rings on the heads.

Thanks for calling David and confirming the error. Did David say that he would update the drawings in his plans book file for future printings of his plans book?

I will be installing the lead screws in my gantry and z axis this weekend. The aluminum stepper plates were made a couple of months ago. There's a good chance that the holes in my gantry and z axis are off enough to compensate for the misalignment (or make it worse) since they were drilled in wood on a shaky old drill press. The error is only 0.01772".

CarveOne

[Tayloned]

CarveOne,

Thanks for your suggestion.

With regard to the geometric errors in David Steele's plans; The Y-axis is also out of align by a similar amount. David's response is that he is working on a new version and the current plans use hole sizes large enough to cope with the errors as the user can align the axi by hand. Plus a 1/16" grid was used to draw the components and hence the max. accuracy is governed by the grid used.

However, should the stepper motor plate be drilled using the holes in main wood parts, then any miss alignment is sizeably reduced. Plus smaller drill sizes equal to diameter of the carriage bolts can be used to further reduce and simplify assembly without all the fiddlely trial and error process to align the shafts.

Also the critical nature of wooden parts being parallel is NOT stressed in the plans. This is especially true of the Z-axis backplate. Any errors here cause problems of the bearing trucks at one end only partially contacting and unevenly running on the Y-axis beam. The same is true for the router Z-plate.

Hope this helps. John R.

[CarveOne]

Thanks for getting David to clarify this error for us and correct the plans book.

I drilled my critical wood parts in my milling machine separately as I did for the aluminum stepper plates. I didn't bother to recalculate the dimensions as you did. All of the stepper mounting screws aligned with the plates, and the shaft hole in the stepper plates looked right by eye. The stepper plate mounting bolts appeared to align also. When the steppers are turning under power I guess I will see any serious misalignment, as the flex couplers will be bending if the stepper shaft to acme lead screw is mis-aligned.

CarveOne

[Tayloned]

Thank you CarveOne for your reply and comments. The oversized holes used in the plans will allow correct alignment, but if you drill the holes using the same diameter as the carriage bolts, the mis-alligmnet becomes visible. Hence my suggestion in previous post.

Have had some family matters to resolve and therefore no progress on building router to date. Hope to re-start and post some photos shortly.

Kindest Regards, John R.