New Machine Build CNC router build to machine wood and aluminium (1mX1mX0.4m) - Page 4

# Thread: CNC router build to machine wood and aluminium (1mX1mX0.4m)

1. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Hi Rupesh - try here
Screws Nuts Washer Sizes Peter

2. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Thanks Peter.

That helped. If I keep 15mm Dia for a M15 nut it falls under H tolerance class which has no-tolerance fit and this is why its so tight. I need to make the shaft around 14.8/9 to get a easy but still no-play fit (4g6g class).

This led me to beautiful website.

Metric screw thread: M Profile calculator

Thanks a Ton!!

3. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Originally Posted by Tony_Stark
The height really gets the attention, isn't it. :P

I think that is why Peter suggested to make web for the columns to prevent that twist action. I think for my application the total Z travel can be cut a bit and the horizontal spread can increased. But I am still figuring it out.

I have no access to my laptop untill next mid week. meanwhile, I practiced threading for ball screw end on a aluminum round. The end nut at the coupling block side is M15 for 2005. The nut is M15X1. So I set my lathe to cut a pitch of 1mm. can any one tell if there is any formula to calculate the shaft diameter for cutting a M15 thread. Does it has to be 15mm exactly or less and then thread is made over it. Cause the nut is fitting over it but its very tight. I have used 60 deg thread cutter tool.
You don't normally need the diameter to be more than ( .1mm ) under or a diameter 14.9mm this will depend on the quality of the nut, if the bearing size is 15mm then this will let the bearing slide over the thread as well

4. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Originally Posted by mactec54
You don't normally need the diameter to be more than ( .1mm ) under or a diameter 14.9mm this will depend on the quality of the nut, if the bearing size is 15mm then this will let the bearing slide over the thread as well
Thank you Mactec.

I will look for a external thread die as my lathe leadscrew has some play which is ruining the threads cut on it. M15 is an odd no, hope I get it here. Meanwhile I would like to share my experience of machining the ball screw. I searched the forum and found some technique. I hope this will help others too.

Ballscrew, It tough, really tough. Initially I started machining using carbide tool. Two carbide tool became dull in going through just the threads and then it became work hardened. Then I had to heat the ends by a portable propane torch to realign the grain structures and relieve the stresses (Annealing). I heated it for like 5 minutes till it started glowing dull red and then let it cool for another 15 minutes. After that it was cutting like a butter. I could cut through it using HSS tool. It just the tool will get dull frequently. So a carbide is better here.

To ensure the heat doesn't dissipate to other threads, I used some wet rag wrapped around the ball screw where heating was not required. First attempt was not that good, some heat went through and discolored 2-3 threads. But on the other end (floating end) I could keep it well within limits. Its easier to machine once annealed. On the floating end I just heated it and let it air cooled and then machined.

As I have a mini lathe and I can't admit much within the centers, I made a arrangement to stop whipping of the ballscrew. You can see the arrangement . Just machined a aluminum round and press fitted it at the other end of the lathe spindle. That limits the whip but doesn't eliminate it completely. I avoided tail end support here as I could not get the ball screw it centered in three jaws. I used a coca cola tin can in-between jaws to avoid any dent on the ballscrew. Then checked the centricity using a dial gauge. I positioned it in the ball groves and turned the chuck by hand simultaneously moving the carriage to keep the dial at in the groove. Works ok. Could see 1mm deviation but I should be ok with that.

Once I was close to the bearing fit, I used emery paper to make the final fit. This is a time consuming exercise but worth doing and one should not to rush. One sec its too tight and other sec its wobbling.

@peter. I got the angle grinder from STANLEY 900W. I think this would be enough to cut the aluminum using cutting blade. Need to think of some guide to keep the cutting straight. Also, I got the next batch of rail guides. I will get my laptop in 2 days. Then I plan to finish designing in another two and hopefully will start by the coming weekends.

5. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Originally Posted by Tony_Stark
Thank you Mactec.

I will look for a external thread die as my lathe leadscrew has some play which is ruining the threads cut on it. M15 is an odd no, hope I get it here. Meanwhile I would like to share my experience of machining the ball screw. I searched the forum and found some technique. I hope this will help others too.

Ballscrew, It tough, really tough. Initially I started machining using carbide tool. Two carbide tool became dull in going through just the threads and then it became work hardened. Then I had to heat the ends by a portable propane torch to realign the grain structures and relieve the stresses (Annealing). I heated it for like 5 minutes till it started glowing dull red and then let it cool for another 15 minutes. After that it was cutting like a butter. I could cut through it using HSS tool. It just the tool will get dull frequently. So a carbide is better here.

To ensure the heat doesn't dissipate to other threads, I used some wet rag wrapped around the ball screw where heating was not required. First attempt was not that good, some heat went through and discolored 2-3 threads. But on the other end (floating end) I could keep it well within limits. Its easier to machine once annealed. On the floating end I just heated it and let it air cooled and then machined.

As I have a mini lathe and I can't admit much within the centers, I made a arrangement to stop whipping of the ballscrew. You can see the arrangement . Just machined a aluminum round and press fitted it at the other end of the lathe spindle. That limits the whip but doesn't eliminate it completely. I avoided tail end support here as I could not get the ball screw it centered in three jaws. I used a coca cola tin can in-between jaws to avoid any dent on the ballscrew. Then checked the centricity using a dial gauge. I positioned it in the ball groves and turned the chuck by hand simultaneously moving the carriage to keep the dial at in the groove. Works ok. Could see 1mm deviation but I should be ok with that.

Once I was close to the bearing fit, I used emery paper to make the final fit. This is a time consuming exercise but worth doing and one should not to rush. One sec its too tight and other sec its wobbling.

@peter. I got the angle grinder from STANLEY 900W. I think this would be enough to cut the aluminum using cutting blade. Need to think of some guide to keep the cutting straight. Also, I got the next batch of rail guides. I will get my laptop in 2 days. Then I plan to finish designing in another two and hopefully will start by the coming weekends.
The Ballscrews are case hardened so can be a challenge to machine but doable with the right inserts heating is one way as long as the heat does not travel to far up the screw, you should thread it with the lathe as much as you can as using a die will not cut a square and parallel thread which is needed for the nut to lock up square against the Bearing

I hope you mean 0.1mm 1mm would not be good

6. Originally Posted by mactec54
The Ballscrews are case hardened so can be a challenge to machine but doable with the right inserts heating is one way as long as the heat does not travel to far up the screw, you should thread it with the lathe as much as you can as using a die will not cut a square and parallel thread which is needed for the nut to lock up square against the Bearing

I hope you mean 0.1mm 1mm would not be good
Oh,Is it. Then I need to practice more on threading to perfect it. Also I will try some mean to bring down to 0.1mm. I have not machined the floating end completly so will tune and try bringing it around 0.1mm.

7. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

one thing that helps keep the screw centered in the chuck is to cut a sleeve to slide over the screw with a split down the length of the sleeve so when you tighten the chuck it acts like a collet. just put the split on the sleeve in between the chuck jaws. self centering chucks could work but a 4 jaw chuck and a indicator would probably be better since it can get adjusted. the bore of the sleeve should be as close as you can get to the O.D. of the screw so your turns are concentric with the screw. Another thing the sleeve does, is to give you something better to indicate in. just set an indicator to zero when it barley touches the sleeve so it does not bounce to much when it passes over the split in the sleeve.

it's good that the ball screw was hard to begin with. now you know it's made well.

8. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Originally Posted by Tony_Stark
Oh,Is it. Then I need to practice more on threading to perfect it. Also I will try some mean to bring down to 0.1mm. I have not machined the floating end completly so will tune and try bringing it around 0.1mm.
Even 0 .1 is a big number Ballscrews are normally machined very precise .003mm or better

9. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

I tried yesterday and after ten minutes of adjustment I brought it down to almost none. The dial gauge I have has a least count of 0.1mm. I couldnot see it move between the division. It just move very fine. so I think it must be perfectly centered. But I need to find a way to make it easy to do. the trial and error adjustment consumes hell lot of time.

The CAD work will speed up now. I got the laptop which has solidworks. I also found out that getting the profile is very costly due to low volume and also its not available locally. I need to replace those with some other structure may be by hollow MS square?.. I probed the local market here. while I can get all the aluminum sizes, Getting profile is seems far fetched. Need to modify the design.

10. Originally Posted by machinedude
one thing that helps keep the screw centered in the chuck is to cut a sleeve to slide over the screw with a split down the length of the sleeve so when you tighten the chuck it acts like a collet. just put the split on the sleeve in between the chuck jaws. self centering chucks could work but a 4 jaw chuck and a indicator would probably be better since it can get adjusted. the bore of the sleeve should be as close as you can get to the O.D. of the screw so your turns are concentric with the screw. Another thing the sleeve does, is to give you something better to indicate in. just set an indicator to zero when it barley touches the sleeve so it does not bounce to much when it passes over the split in the sleeve.

it's good that the ball screw was hard to begin with. now you know it's made well.
The sleeve idea is great. I will machine one and see if that makes things easier for me.

11. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

it's about impossible to indicate a screw because of the pitch of the screw is not suited for locating the concentricity of the shaft, the split sleeve gives you 4 points 90 degrees apart from one another to indicate in so you have next to no run out on your bear block diameters of the shaft. it works really well as long as the sleeve bore is almost a bearing fit. it should just barely fit over the screw with out having to force it before you cut the split in it. once you cut the split it will probably spring open some but that is ok since the chuck will compress it around the shaft when you do the machining. just take your time getting a nice fit over the screw before you split the sleeve so you don't get to much run out.

12. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Yes, that's sound perfect way to do it and make sense. I tried putting a flexible strip over the screw while holding its one end in the tool post i.e. The rectangular strip's one end was clamped in tool post and other end lying over the screw. This way it help see the deviation but still this is not that perfect way of doing- just a makeshift.

One correction in my earlier comment:

I just checked, the dial indicator has 0.01mm as least count and all long I was counting 0.01 as 0.1mm. WTH. So when I mentioned the deviation as 1mm in my previous post it was 0.1mm at that time.

13. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

.01mm of run out is pretty good and i think you would be fine up to .03mm of run out. the flex coupling will compensate for some minor run out. i would try to get it as close as you can regardless since the less you have the better off you are. the small hobby lathes should be able to do better than .1mm that's close to .004 imperial and that is getting out way more than what you want. the method i explained should get you into the .03mm or better range if you take your time with it. i have a 9" x 21" hobby lathe and i was able to make a spindle with .0002 imperial of run out on that machine so it's hard to do much better than that with the hobby machines.

14. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

I have been working on the CAD for sometimes now. Made some crucial changes to the design to increase rigidity. Made the gantry column thicker to 20mm. Provided extra support at the back of the plate holding Z axis. Also increase its total height. I have also increased the base to 700 (from 640). That led to some decrease in Z axis overall travel. The total travel is 14.5mm for Z. The height of the gantry is adjusted to account for the waste-board and vice.

I don't have time to learnt the FE now but I hope this design will hold the ground. The availability of Al extrusion is still a question. I will keep it open at the moment and will modify on the fly with whatever I get my hands on. I will replace it by mostly by aluminum plates.

I have been thinking of how I will be connecting all these part as I have not worked on that in the CAD. Most of the parts will be bolted together or screwed on. Where ever possible I will use angle as an extra strength for parts connecting at 90 deg. My drill press can only admit parts upto 500mm, will have to buy a hand drill machine to drill on many parts. Contemplating!!!

15. Originally Posted by philba
Hi, Tony. I didn't see that you decided on a controller yet - you might consider 32-bit GRBL. While the old 8-bit GRBL has a lot of limitations, the "HALified" 32-bit version has removed them - most notably, step rates of over 200 kHz are supported, you can have up to 6 Axes and Ethernet interface. It runs on a wide range of microcontrollers - 13 at latest count. You can find out more about it here: https://github.com/terjeio/grblHAL. No SW license fee required - it is opensource. The test branch has autosquaring for ganged axes (like you recently moved to) and a really nice configuration section. It should be moving over to the master branch in a week or so. I'm running it on my small router. Several people are running it on ganged axis machines like yours. I have a breakout board on Tindie for the Teensy 4.1 (600 MHz ARM Cortex-M6 processor) - https://github.com/phil-barrett/grbl...ster/README.md. I call it an unkit - all SMD components are there, you just add easy to solder through holes components like connectors and the Teensy. All in cost including connectors and the Teensy is about \$65 USD. Though, schematics, gerbers and an OSHPark upload are available if you want to build your own. Worth checking out.

Attachment 448288
Hi
I need help
I have got cnc machining center with fanuc m15 control
I lose all parameters
I need parameter manual
I won't to adjust number of axis
Now only x axis appears on screen
Please send me how to solve this problem

16. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Hi Rupesh - Some sort of game plan is useful at this point for the materials. For instance the 20mm columns. Buying a small qty of 20mm plate is expensive. But lets say you are going to make everything from 16mm or 12mm. Then instead of making the column 20mm you use a web which is stiffer and comes from the same plate you bought. The company that you buy plate from may be able to rough cut for you. 16mm is a good size its thick enough to use big screws in its edge. This also means you can prototype in 16mm MDF before you commit to the plate. If you use 12mm you can use brackets cut from channel or angle or use cast angles or edge bolt if you cab cut very square. You need to resolve your material supplies otherwise you are going to burn up lots of time and have too many dead ends and re designs. Cheers Peter

17. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Peter, pardon my ignorance but what is web look like? what kind of structure you mean when you say web?

18. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Hi Rupesh - I did a drawing earlier on the side of the column. A web on the side is stiffer then going from 16mm to 20mm flat plate. Peter

19. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Oh yes I remember.Got it Peter.

20. ## Re: CNC router build to machine wood and aluminium (1mX1mX0.4m)

Originally Posted by peteeng
Hi Rupesh - I did a drawing earlier on the side of the column. A web on the side is stiffer then going from 16mm to 20mm flat plate. Peter
That will not help. Any "webing" on the column is nonsense. It just beatiful, nothing more.
At mill machine, you need mass, mass, and mass again. You need to consume vibration, and no "webing" ever eat that vibrations. That only do mass itself. Only choice you need to make is decision, how much mass you want to invest in you mill. Thats the point.
You are building hobby machine. So you will probably do not want a 1ton machine, but if you want to cut any harder material than polystyrene, you must invest some mass (= material) to consume vibrations. I also did this mistake like you are doing now, and I will never do that again. You will spent a hundreds hours to make it alive, probably a few thousands dollars, so you really do not want to watch (and hear) a router bit avoiding material because the weak portal, because you want to save a few tens of dollars on material.

Just be smart - if you are cutting aluminium, you make cuts 0,03mm each rotation (0,03 per teeth). So if you will push your spindle in any direction with app. 30-50kg force, than the construction must not to move more that 0,03mm. Thats your goal. And any webing will not help you with that.

Ok, you surely can make cuts with weak machine, but only with small diameter, thats mean you will probably not be able to cut through 10mm aluminium because of short small diameter bit. And speeds? Precision? You will need to make a several finishes to reach 0,05mm precision instead of just roughing, make one finish, and insert a bearing.

I can send you a drawings of my latest machine, its very simmilar to yours you want to build. There is no complicated parts, simple to build, like yours, but this machine have 0,012mm repeatable precision, cutting aluminium with 12mm bit like a butter. You can inspire with that. And not to make mistakes like I did at my first machine.

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