Definately a scrapyard challenge

[Jonathan]

The problem is every time you mention 1610 screws it makes it sound like everybody has to rush out and buy them??????

In my opinion 1605 has very few advantages over 1610 for a router, which is why I recommend it so often.

just remember to when you first started mister and how difficult it was.

When I was designing my router, the rotating ballnut design was far more difficult that picking the ballscrew, but that's just my opinion.

I use 1605 screws and belts on mine and it is more than enough for it's job, i could have my X axis twice as fast as yours with the belt but it would be pointless.

Even if you manage to get 60m/min, it will only be for a short time before failure. Realistically it's impossible. In terms of speed and acceleration 1610 screws outperform 1605 by a large margin. Even hypothetically running a 1605 at 2:1 is still inferior in performance to a 1610 at 1:1 due to higher K.E.

I started with a 2mm pitch screw on Y and 2.5mm on X since that was the biggest I could afford at the time (not ballscrews), and I made a rotating nut for X to compensate and that funny wonky bearing drive, that I wish there was a simple name for, on Y to lower the friction.

[JAZZCNC]

In terms of speed and acceleration 1610 screws outperform 1605 by a large margin. Even hypothetically running a 1605 at 2:1 is still inferior in performance to a 1610 at 1:1 due to higher K.E.

Ok can't resist got to jump in.!!!:twisted: . . . Don't need to worry about 5mm pitch being inferior because of K:E bull shit etc because it don't mean jack shit for a DIY machine, it will still perform more than good enough.! . . ( If built good enough.!!)

Yes jonathan's correct when he points out that the calculated physics way of looking at it that 10mm pitch wins for a router!. . . BUT. . . I can tell you because my machine use's 5mm pitch geared 2:1 it's absolutly no problem and in no way limits the performance. Actually IMO it's a bennifit because it's just a simple belt/pulley change to gain resolution.

That said I agree that 10mm pitch (except Z axis then 5mm) would be better choice for a router which mainly cuts wood or plastics. Anything harder IE Ali etc and then extra speed 10mm pitch gains is wasted as the feed rates dictate. 99.9% of the time you'll be lucky to cut any where near quarter the speed 10mm pitch allows.!

An often over looked and misunderstood area which Jonathan touched upon earlier is acceleration.!! . . . IMO and experience for most jobs (Esp 3D) that don't need high feeds (2mtr/min or less) then your much better off tuning your motors to give higher accel than velocity. . . Often less is more.. . Like in the Aztec case where there are lots of short moves it can and does often make job's faster. 3D and v-carving really see the most increase's from high accelleration.

I use Mach3 and it's such a simple job to create profiles that you can easily tailor for specific job types or conditions. IE I have 3D profile tuned for Accelleration. 5mm pitch profile (pulley/belt change)for when resolution needed. I also have profiles for Inch units for each so when I get given code that use's imperial measurements I don't have to fanny about changing settings or code.
Doing it this way makes it very simple and quick to change from one to the other.

So Like 2eOpoz I 100% agree 5mm pitch will be fine in your case.!. . . . BUT . . . 100% Agree with jonathan 10mm pitch rules for a wood/plastic router.

Anyway the screw pitch or speed will be the least of your troubles if you don't beef that gantry up.!!

[Jonathan]

Don't need to worry about being inferior because of K:E bull shit

I think you'll find just about everyone apart from you agrees kinetic energy isn't 'bull shit' and is very important, I'm not even going to argue this point because it's so widely accepted. No matter if a machine is made in a home workshop or professionally, it can't escape the laws of physics. A 3nm Nema 34 motor wont go as fast as a 3nm Nema 23, it's due to exactly the same calculation!

my machine use's 5mm pitch geared 2:1 it's absolutly no problem and in no way limits the performance. Actually IMO it's a bennifit because it's just a simple belt/pulley change to gain resolution.

As far as I'm aware you've not tried 10mm pitch rails on your router, so I can't see how you could possibly know that. I'm well aware that you don't respect calculation, and that might well be true for you, but for just about everyone else, calculation plays a hugely important role, and if it didn't work like you say, the theory simply wouldn't be there.

it's just a simple belt/pulley change to gain resolution

That clearly also applies to 1610 so it's not a benefit. Since you only recognise empirical evidence, your version of the Mayan calender I cut on 1:1 looks amazing.

99.9% of the time you'll be lucky to cut any where near quarter the speed 10mm pitch allows.!

It's not about cutting faster, it's the acceleration gain from using 10mm pitch that's most important. You told me your acceleration on the Y-axis is 900mm/s/s, with 5mm pitch. I now have mine set to 2000mm/s/s with 10mm pitch (more shakes the machine too much).

I get the impression you think I'm saying 5mm pitch won't work, seeing as you say "it will work fine". I agree with that, but when designing a machine I think it's foolish to aim for it working fine, you should aim for it to work as well as possible, not just well enough and 5mm pitch screws will simply limit the potential of your machine.

I'm not going to say anything more on the subject since apparently it provokes a particularly strong reaction, I think motoxy has all the info to make an educated decision. Good luck.

Motoxy: There's a quote for that - The more I know, I know, I know the less. (John Owen)

[JAZZCNC]

Jonathan . . .My point was that 5mm pitch geared 2:1 works fine because I use it.!. So all your bullshit spouting about K:E means sweet F:A whether nema 23 or 34 because for 99% of DIY use both are far more than good enough.

Also If you look again ya touchy lickle git you'll see I agreed with you on the 10mm pitch.!!


Presumption is the mother of all F:U.!! . . . SO NOW. . How the F~@K do you know what I've done or not done with my machine.? Or any other machine for that matter.:exclaim: . . . . . reading a few old post's don't make you Physic Sally.

If you want to get into machine design and foolish ness. My approach is that you build a machine to be strong and accurate as possible to do the best it can at it's intended purpose.! .. . To build with just speed in mind at the sacrifice of accurecy, repeatabilty resulting in poor quality in-accurate work.!!. . . is plane stupidity IMO.

Now wasn't having a go at you or saying what you said was wrong or wouldn't work so suck your petty lip back in and drop it.!:tup:

[motoxy]

Just ordered my spindle and inverter. Made an offer of £140 instead of £172 and it was accepted:dance: Other than postage that makes it the same price as a Kress. Bargain.

Now off to redesign the gantry.
Bruce

[motoxy]

OK Here is a thought on redesigning the gantry. Any similarity to Jonathan's machine is purely down to plagerism. I have looked at a construction that I can do myself. I will make some enquiries tomorrow about acccess to a m/c shop.

[Jonathan]

Any similarity to Jonathan's machine is purely down to plagiarism.

Problem with plagiarism is, as they always tell you at school, you copy other people's mistakes! I've put the ballscrew on the Y-axis of my machine in a sub-optimal position, which you've copied! It needs to be closer to cutter / between the rails. The problem is everything between the cutter and ballscrew can deflect, as the linear bearings don't offer much support in that direction. I posted more about it here:

http://www.mycncuk.com/forums/showth...h-X-and-Y-axis

(But don't start thinking of two ballscrews like I suggest there - it's excessive! Just put the ballnut on the other side.)

[motoxy]

Just got another computer. Has seperate video card and plenty of memory. Came without a drive so I am just doing a clean install with xp. I will need to study the board and cards and get some drivers.

Ever noticed how confusing it is to be using 2 computers at the same time. Keep using the wrong keyboard and wondering why nothings happening. Oh well.

Bruce

[motoxy]

Well I think its about time to get my motors, drives etc. and couplers. I have looked at diycnc, zapp, cncrouterparts and cnc4you. Any others I should check out or any advice to be had? Probably have to buy the power supply in uk to avoid 110v.

Bruce

[motoxy]

I know what your thinking, here's another of those that start a build log but do not build.

SURPRISE

I have started the rebuild. I have put registers into the top and bottom plates of the z gantry and started drilling and tapping to connect. The I used my home made
under the bench router table. I know it will not be with a tight tolerance but I kind of got the urge to do as much as I can on my own. That said its thank you to Jonathan for a fine pair of ball nut brackets and spindle mounts.
Do not expect this to be a speedy build. As you can see I have done 3 bolts so far.:whistling: