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Tom
07-08-2010, 10:53 AM
For sale on ebay. A new improved design over what my router is currently running. Helpful for new builds (I found the motor mounts on my build very fiddly with few tools to help me).

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=140435943357

25732574

Comments / feedback welcome. Also, if you've got any ideas for similar components you need to help you out, let me know.

Cheers,
Tom

Scott
07-08-2010, 04:45 PM
might just be me but it looks like you loosing steps or calibration need looking at or it could just be the picture
like the design those spacers are a good idea makes adjustmet easy

Tom
07-08-2010, 06:13 PM
Yeah, you're not wrong - there are a couple of things I'm planning to improve on this machine. All fixed this week, and none affect the function of this part. :beer:

Backlash in X (causes poor text resolution)
Gantry flexibility parallel to Y (causes the wavy edge on X direction cuts)
Z not quite normal to the table (causes the "stepped" appearance to the cuts, where each pass is visible separately)

Cheers for the feedback! :)

GeorgeD
08-08-2010, 09:25 AM
Did you know that MDF expands and contracts in different climatic conditions,Tom. :wink:


Thats why I never even considered MDF in my build(When I get round to it) :whistling:

irving2008
08-08-2010, 11:29 AM
Did you know that MDF expands and contracts in different climatic conditions,Tom. :wink:


Thats why I never even considered MDF in my build(When I get round to it) :whistling:
yes it does when it absorbs moisture... which is why you need to seal it with paint or other sealant. But for a wood and plastics-cutting router/mill MDF is a perfectly good material for a starter machine as many have demonstrated.

GeorgeD
08-08-2010, 12:48 PM
yes it does when it absorbs moisture

So it won't expand from the heat generated from the stepper motor?

GeorgeD
08-08-2010, 12:59 PM
A test just done on a piece of 25mm MDF measured with my digi caliper,applied heat from a paint stripper gun for 1 minute and measured 25.18mm.

John S
08-08-2010, 01:04 PM
If you steppers are getting as hot as a paint stripping gun you are doing something wrong - take up knitting.

.

GeorgeD
08-08-2010, 01:10 PM
Are you saying they don'tget hot after 2 or3 hours constant use? all motors get hot in constant use.

John S
08-08-2010, 01:22 PM
George,
Lets look at this logically. Anyone building a stepper driven MDF machine isn't looking to hold 0.001" on it.
By virtue of using MDF and threaded rod for lead screws the build will limit then to far more than this.

Your 0.18mm with a heat gun is far more than a stepper will get and if you are using decent drivers the motors drop back to half current when parked so working hard they will only get reasonably warm.

Where MDF scores is it's cheap and easily worked which means a beginner can quickly cut their teeth on the MKI router which often leads to the MKII and so on.

.

irving2008
08-08-2010, 01:45 PM
Exactly right John.. the issue, George, is that you are not applying engineering pragmatism and and element of real-world experience to the problem. A really hot stepper gets to 80degC max.. but is easily able to radiate that heat... your heat gun is easily 3 - 4 times hotter then that and is heating the air around the test piece too, so your test isnt representative... apart from the points John makes

ecat
08-08-2010, 02:24 PM
Firstly, temperature (kinetic energy) does not equal heat (the transfer of energy). A stepper motor generates X watts of energy ( J/s ), the heat gun generates Y watts. X is probably less than 100w (?). Y is probably in excess of 1kw.

Secondly, I look at these mounts as a metal studded rod mount with MDF spacers, the metal rods (in tension?) provide a lot of stability, the MDF (in compression?) doesn't really have any where to expand into.

Third, the shaft coupler should take up any small variation.

Feel free to correct any of this, as if an invitation was required lol.

Tom
08-08-2010, 03:08 PM
Small print:

* attack by paint stripping gun may degrade performance.
* attack by paint stripping gun may not degrade performance.
* may contain nuts.

Thanks for the interest everyone! lol
Any suggestions from people who need other MDF bits made? Send me a PM. (Suggester / first user / beta tester gets their parts for free....)(within reason).

Scott
08-08-2010, 03:16 PM
i think most people know that if they build a machine out of MDF it`s not going to be 100% accurate

Ross77
08-08-2010, 03:35 PM
Secondly, I look at these mounts as a metal studded rod mount with MDF spacers, the metal rods (in tension?) provide a lot of stability, the MDF (in compression?) doesn't really have any where to expand into.

Correct, which begs the question is all that mdf needed? I would have just used the front and back plates and then spacer tubes on the threaded bar. But as John said, I think analysing MDF to this degree is unnecessary as it will typically be a first build.

routercnc
08-08-2010, 08:56 PM
Hi Tom,
Nice little units - and love the small print, made me chuckle. Some people eh?

Personally I would use plywood, just because I don't like MDF dust, but the concept is sound. My first machine did use 4 spacer tubes as Ross suggested, but if you have limited hand tools it can be tricky to cut 4 tubes exactly the same length. There are ways of course, but the spacers guarantee a pretty square mounting surface.

George,
Think, then type, not the other way around :wink:.

Tom
08-08-2010, 11:33 PM
.... is all that mdf needed?

I really like the design process. Now you mention it Ross, it probably isn't. I like bolting through a wide face of MDF because it adds plenty of torsional stiffness, but there probably isn't the need for 3 closed sides. If I made the spacers separate (2 on each layer) it'd save some raw material, a tiny bit of cutting time, and some weight. Mk3 on the way... :)

Thanks for the complement Barry...

John S
08-08-2010, 11:51 PM
I like the closed sides it gives stiffness, the problem with spacers is that there is no torsional stiffness and it looks like grandads mantlepiece clock.

Ross77
08-08-2010, 11:56 PM
Hi Tom
My coment wasnt a dig at your design and is more a reflection on my bad posting, I was meaning it as a way to reduce any expansion in the mdf due to paint striping gun :heehee:

Tom
09-08-2010, 09:48 PM
I appreciate the comments, Ross - all positive input! On balance though, I think laziness wins (I can always say it's for improved torsional rigidity, a-la-John S)(I don't like mantelpiece clocks either).

routercnc
09-08-2010, 10:17 PM
Hi Tom,

Something else that beginners may want machining is a holder for a Dremel tool or similar. Some kind of clamp to attach it to the Z axis.

GeorgeD
12-08-2010, 09:53 AM
No takers for you mounts there,Tom.

Back to the drawin board,you'd have been better cuttin them out of Nylon block sheet off ebay.

http://shop.ebay.co.uk/?_from=R40&_trksid=p3907.m570.l1311&_nkw=nylon+sheet&_sacat=See-All-Categories

Lee Roberts
17-08-2010, 03:18 AM
Tom,


Great effort and thank you for offering your services!


Here is what I did, with hand tools. Maybe you could speed things up by using your cnc machine.

What do you think Ross? lol

Tom
17-08-2010, 08:28 AM
Thanks Lee,

Yours is alot better than my 1st effort (which lasted not very long at all!) :)

Barry, A router mount is a good idea - I'll get on it. Kress is 43mm, Trend is ??mm (maybe 42?), and proxxon is 20mm. Not sure what dremels are.

Like I mentioned before though, if anyone has bits they need cutting let me know. I'm happy to work on the bits people need before they get to the router mount.... :)

Tom
17-08-2010, 08:37 AM
By the way, the MDF motor mounts are still on sale, and doing well. One happy customer anyway!

I deleted the text because it wasn't functional, and reduced the cost.

http://cgi.ebay.co.uk/NEMA-23-CNC-Motor-Mount-MDF-DIY-CNC-Machine-/140439650792

GeorgeD
17-08-2010, 10:20 AM
Still think you'd be able to charge more with them made in Delrin or Nylon and you wouldn't need spacers...well you could throw in one for longer mounts?.

John S
17-08-2010, 01:46 PM
Well there you are George, a niche market you can patent and sell - go for it...............

.

GeorgeD
17-08-2010, 02:02 PM
If I'm going to make something and sell it... like to think it would be worth getting out of bed for,John. :wink:

Lee Roberts
17-08-2010, 03:22 PM
By the way, the MDF motor mounts are still on sale, and doing well. One happy customer anyway!

I deleted the text because it wasn't functional, and reduced the cost.

http://cgi.ebay.co.uk/NEMA-23-CNC-Motor-Mount-MDF-DIY-CNC-Machine-/140439650792

Some more options for you:

Lee Roberts
17-08-2010, 03:24 PM
Well there you are George, a niche market you can patent and sell - go for it...............

.

I was thinking of patenting these badboys John...what do you re'con !?

GeorgeD
17-08-2010, 05:10 PM
I'm sure dice don't have an hole in the center.:wink:

Tom
17-08-2010, 06:38 PM
Geoffrey, sorry, George,

To sell something there has to be a market. Have you ever looked at the price of the raw material you're talking about? Once you've added that into the selling price I think your market for simple cheap motor mounts disappears.

You haven't mentioned what profession you've retired from, but I'm willing to bet it wasn't engineering.
Engineering 101:
Doubling or quadrupling price must double or quadruple performance/usefulness to customer. Otherwise which fool is going to pay?!
True, plastics could be stiffer (though not measurably in this application), and they may be more dimensionally stable (measurable but not functionally important in this application), but they're not 200% stiffer and 200% more stable.
End of lesson.

If you find an exception to that rule (a fool who IS willing to pay) I suggest you don't post it in this thread, but keep it quiet and work on it. Next post should be of the Porsche you've bought with the rude profit made. :whistling:

But most people are not fools. And to those sensible folk who recognise what they're seeing, I am offering MDF motor mounts! :wink: Clicky (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=140439650792)

PS. Thanks for keeping this thread at the top of the replies list. Very helpful. :beer:
PPS. Lee, you can't. My mom has already patented them.... lol

GeorgeD
17-08-2010, 07:16 PM
Otherwise which fool is going to pay?!Same fool that buys MDF mounts.

Whats your problem Tom? I'm only trying to help here and you have a better chance of selling ten Nylon/Delirin mounts faster than its taken you to sell the one MDF mount.

It only takes a shoulder and two spacers tomount a motor plus four bolts and nuts&washers.

Oh and you have also a better chance of selling the MDF mounts in the stepper motor catagory on ebay rather than in the quagmire of the automation catagory.

Ok I'll not bother your post again.:rolleyes:

Tom
17-08-2010, 07:46 PM
Thanks for your suggestion about the stepper motor category - it's genuinely useful.

As for the other comments it's the tone that doesn't sit well. If they're helpfully meant it certainly doesn't come across that way. I'll list them in order for you...


Thats why I never even considered MDF in my build(When I get round to it)


measured with my digi caliper,applied heat from a paint stripper gun for 1 minute


Are you saying they don'tget hot after 2 or3 hours


No takers for you mounts there,Tom. Back to the drawin board,


like to think it would be worth getting out of bed for,John.

And finally,

Same fool that buys MDF mounts.

See what I mean. Not exactly open-minded, inclusive, constructive comments are they. In the month you've been a member on this site, very similar stuff has been plastered over almost every thread. George, if you dish this rubbish out, you've got to be able to accept it back occasionally.

I'm only sorry that I was the one who stooped low enough to dish it out publicly. Since no-one wants to read this stuff (what does it have to do with CNC?), lets stop here. Thanks.

GeorgeD
17-08-2010, 07:58 PM
Oh for heavens sake,has all that wound you up? they're my views on MDF,Motors do get hot when run constantly, 3rd to last quote was a light jesting and the 2nd to last quote was an answer to Johns post not aimed at you or your MDF mounts ie I wouldn't get out of bed for a job that didn't pay less than £10 an hour in general.

And the last question is true.

Swarfing
17-08-2010, 09:59 PM
I bet you would gt out of bed for a cuppa T? and that would cost you instead of paying you. George i really do think that you do not think? I think that you think that you think but really you never think? sometime opinions are there to show a different light or help for improvement. They can also be there to save a mistake for later? trouble is your opinions save nothing and later is always sooner for you....................

That is my opinion and if anybody else would like to take anything from that opinion it may save a mistake for you? I teach my kids that the biggest rule in life if you want to get on is to listen listen listen, if you don't you learn nothing.

Swarfing
17-08-2010, 10:00 PM
By the way the mounts are great idea and proves you listened to something to get a good idea going in the first place ;-)

John S
17-08-2010, 10:12 PM
No we are all waiting for Georges brilliant router build so we can all take the piss out of that. What goes round comes round.

Full marks to Tom for getting out of bed and making something that can [a] help others with their build and [B] give him an incentive to use and improve his machine.

routercnc
17-08-2010, 10:23 PM
Looking forward to seeing that build too . . .!

George. Your posts tend to come across as someone with extensive knowledge about the subject, giving out pearls of wisdom, yet at the same come across as someone who is just starting out on the subject. By your own admission you are a beginner, and therefore this is generally annoying.

Ross77
21-08-2010, 01:31 AM
Tom,


Great effort and thank you for offering your services!


Here is what I did, with hand tools. Maybe you could speed things up by using your cnc machine.

What do you think Ross? lol

Looks damm fine to me, but maybe if you added this (http://www.google.co.uk/imgres?imgurl=http://www.mkclocks.com/images/quartz_mm.jpg&imgrefurl=http://www.mkclocks.com/anchor-m-23.html%3Fsort%3D4a%26page%3D1%26osCsid%3Dbpcpah02 osvb0in4bqg374jsd0&usg=__4vQIuJCGZuIgXUxF6f6JuxhQzcY=&h=488&w=600&sz=71&hl=en&start=0&zoom=1&tbnid=5Rg-D1StbIHiOM:&tbnh=129&tbnw=170&prev=/images%3Fq%3Dclock%2Bmovements%26um%3D1%26hl%3Den% 26safe%3Doff%26sa%3DN%26rlz%3D1R2ADRA_enGB344%26bi w%3D1659%26bih%3D825%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=127&vpy=269&dur=1797&hovh=202&hovw=249&tx=115&ty=108&ei=tBBvTMWyHtObOJ-VyLAL&oei=tBBvTMWyHtObOJ-VyLAL&esq=1&page=1&ndsp=36&ved=1t:429,r:9,s:0) it would keep every one happy :lol:

Lee Roberts
21-08-2010, 02:23 AM
Looking forward to seeing that build too . . .!

George. Your posts tend to come across as someone with extensive knowledge about the subject, giving out pearls of wisdom, yet at the same come across as someone who is just starting out on the subject. By your own admission you are a beginner, and therefore this is generally annoying.

I think the above is all that needs to be said, so letís draw a line under these now guys. I donít want to have to close the thread.
We all know why we are here and that is to steal Johnís hobnobs. There is no right way or wrong way to steal Johnís hobnobs, however my way is the only way it should be done!

Now letís take a minute and enjoy a song:


http://www.youtube.com/watch?v=4BT9hqwYGWA

:tup: