CarveOne's Solsylva 25x37 Router Build

[CarveOne]

I picked up some 1/2 - 10 acme nuts from the local Fastenal store today and will start installing the x axis lead screws tonight. It looks like the only problem I will need to correct is that the 1-1/8" OD ball bearings will have an interference fit with the wood side rails in four places, but a little creative wood removal with a Dremel tool will make room enough that the 1/2" rod will remain in the original 5/16" rod hole centers.

The DumpsterCNC anti-backlash nuts will also work if the round flange is cut off on one side and a new bracket is made to tie the ABNs to the wood block on the gantry end plates.

I'll post some close up pics this weekend once I'm happy with the results.

CarveOne

[pumelloman]

Can't wait to see the DumpsterCNC AB nuts in action, hope to see some pictures!

[CarveOne]

I don't know how long the Delrin ABNs will last but I think that they will "seat" on the threads during operation kinda like piston rings seat in an engine's cylinder. A little light lubrication once in a while may slow down the wear.

Here's a quickie look at one. The challenge is to make a right angle bracket to allow two screws to mount the ABN flange to the wood block. It is shown on the rear edge of the block in this photo, but it may end up facing the other way and mount to the front edge of the block.

CarveOne

[CarveOne]

This is the bracket that I settled on for my x axis ABN mountings. The left side bracket is a mirror of this bracket. Putting it in this position and with the spring end forward does not limit the gantry travel in either direction. Putting it on the rear side of the gantry block would cause the ABN to run into the bearing block at the rear leg. I could remove the gantry block and cut it shorter so that the spring end of the ABN could be under the gantry block but that requires a larger slot in the bracket. So I'll reserve that for later if it becomes necessary. (I'm starting to feel thay way about a lot of these little details. I'm about ready to see this thing run, even before it's finished.)

CarveOne

[CarveOne]

Moving right along this weekend.

I made the purpleheart bearing blocks and have assembled the left side of the x axis lead screw. The right side is ready for final assembly.

The pulleys and belt are scheduled for UPS delivery from sdp-si.com on Monday.

The y and z axis lead screws have not been worked on yet, nor have I made the three stepper cables.

I removed the circuit board from a dead pc power supply with the intent of using the case for mounting the stepper control board. The case has a large (5-1/4" square) 12vdc fan that is in good condition, and an ac power switch. The power supply is 24vdc though. I'm thinking of making a case that can contain the 24vdc power supply and the controller board with two fans for cooling.

CarveOne

[CarveOne]

The pulleys and belt arrived as expected today. Those are the last components that I needed to complete the assembly of the hardware.

Also as expected, the two x axis pulleys do not have enough aluminum hub to bore a 1/2" hole through them so that they fit on the 1/2" acme rods. I can turn the ends of the rods down to fit the existing bore holes in the pulleys and thread the end long enough for two 5/16-18 nuts. I may be able to find another set of larger pulleys with the same ratio and proper bore size. Oh well, there had to be a serious hitch in my git-along at some point in my build, and this seems to be my usual luck with home projects.

Time to go assemble the right side x axis leadscrew hardware.......

CarveOne

[CarveOne]

Looks like I'm in luck with the 1/2" bore 15 tooth XL pulleys. sdp-si.com shipped a pair today even though their website said that they were out of stock last evening. Amazing. I should be finished with the x axis hardware by this weekend.

Now, if I could just win the state lottery..... I would start on my own bigger, faster, fancier cnc router machine build.


CarveOne

[pumelloman]

Originally Posted by CarveOne Now, if I could just win the state lottery..... I would start on my own bigger, faster, fancier cnc router machine build. CarveOne

Looks like everyone's the same, hahaha

[CarveOne]

Pumelloman,

Wishing is free, buying lottery tickets costs money. I'll probably be spending any potential lottery ticket money on my next cnc build.

Made some unexpected progress this evening. The 1/2" bore pulleys arrived today and I completed the left and right x axis lead screw assemblies and installed the belt assembly. Only the right side anti-ballistic nut, errrr anti-backlash nut, needs to be installed on the aluminum bracket.

Because of this good fortune maybe I can complete the y axis lead screw assembly this weekend and start figuring out how to install the ABN and lead screw on the z axis.

The http://www.sdp-si.com part number for the 1/2" bore 15 tooth aluminum XL pulley is:

A 6A 3-15DF03716 (currently priced at usd $9.84 each)

Added photo of belt drive installation.
CarveOne

[CarveOne]

Spent the whole day working on the router machine today. The final assembly of both sides of the x axis is completed.

I made a bracket for the upper ends of the z axis tube rails from 3/4" x 1/8" aluminum angle, two lathe turned steel plugs, and two 12-24 screws. This will be used for mounting a carved purple heart plate when the machine is capable of making one. Not sure what will be on it yet. Sorry about the fuzzy photo.

The ABN will be easy to install on the y axis. A 1" right angle aluminum bracket for it will be finished tomorrow. The bearing blocks have been made but have not been bored and drilled yet. Will do that tomorrow as well, and I hope to complete the y axis assembly tomorrow.

The ABNs put a lot of drag on the lead screws due to spring pressure. If I compress the spring a bit the drag lessens considerably. Seems that the spring needs to be a little lighter design, but maybe the ABNs need some run-in time on them to fully seat in the rod threads. Will ask Tim at DumpsterCNC about this.

CarveOne

[CarveOne]

See photo below for the y axis ABN mounting bracket details.

While working on the y axis lead 1/2-10 acme screw and ABN installation yesterday I found that there is too much flexing and lost motion in the small mounting block that the ABN is mounted to. The block moves laterally when rolling the lead screw a little in both directions. Also, when moving the z axis assembly by hand there is too much movement at this block also. The long 1/4-20 all-thread rods that run through the oak ABN mounting block also have some flex.

In order to eliminate the freeplay problem I'm going to remove the small oak ABN mounting block and long 1/4-20 rods and replace the small ABN mounting block with a longer piece of 1x6 oak that is about 5-1/4" long. Instead of drilling through-holes for the 1/4-20 rods, I'll drill two holes at each end of the block about 1-1/2" deep and spaced the same as they are on the plans. In these four holes I'll install 1/4-20 brass threaded inserts with some epoxy on the outer threads. The long rods will become four shorter pieces that install through the top and bottom plates and screw into the threaded inserts in the new ABN mounting block. The ABN mounting bracket will have obround holes for mounting to the block and for minor adjustment of the ABN position.

This will make the oak ABN mounting bracket fixed in a position where it clears the ball bearing bolt heads and will be much stiffer due to the shorter 1/4-20 rods. The nuts on the 1/4-20 rods can still be used to adjust tension on the y axis roller trucks. The z axis assembly can still be removed when necessary by removing the four short rods from the brass inserts. (Maybe just the upper two rods will allow removal.) Another photo will be posted when this is completed.

The ABN mounting bracket is a 2-1/2" piece of 1/8" x 1" aluminum angle with a 2-1/2" piece of 1/8" aluminum flat stock as a spacer. About 1/4" of the ABN flange was ground off for clearance to the wood block.

CarveOne

Edited: I added two photos of the new ABN mounting block which shows the larger block from both sides. The new block is 5-1/2" x 5-1/2" x 3/4". It should be made 5" tall, as I had to relieve the backside of the block where there is an interference where the bearing bolts are located. I drilled into the block 3/4" deep in four places to match the holes in the top and bottom plates. I then drilled for 1/4-20 x 1/2" long brass threaded inserts and screwed them in place using a T wrench and washer. The washer on the end of the T wrench made sure that the inserts were pulled flush with the end of the block and forced the insert into alignment. (The T wrench is sold at woodworking stores for installing these inserts.)

The four shorter 1/4-20 allthread rods are cut 3" long and I cut a slot in one end of each rod with a Dremel tool and heavy duty cutoff wheel. The slot allows a screwdriver to be used to screw the rods into the block until it seats against the bottom of the holes. Nuts and washers are used on the rods to tension the z trucks as before this modification. The aluminum angle has slotted holes now, and the aluminum spacer under it is made from 1/16" sheet.

This is now a very rigid assembly. There is no noticeable free play or flexing in this connection now. I highly recommend doing this change from the plans even with the original 5/16" allthread lead screws.

CarveOne

[CarveOne]

Last evening I reassembled the y axis ABN mount and edited the last post to include the new photos and description. I continued messing with the adjustments and looking for any new problems with the changes.

I'm really happy with the y axis movements and it seems like a rock solid connection from the leadscrew to the z axis assembly now. All four short 1/4-20 rods need to be removed to take the mounting plate off. There is no slop in the 1/4" holes in the top and bottom plates that the short rods mount through. If there were, additional nuts can be added to the rods so that there are locking nuts on the rods that can be tightened after the tensioning has been completed. I will add them on my machine just so nothing loosens up with use.

CarveOne