Mach3

[Another JohnSParticipant @anotherjohns]

Also, look at diylilcnc.org for the "bolt in the T slot" construction.

Now, the V1 of this that I saw 2 years ago was running LinuxCNC (flawlessly, I might add!) so the topic of this thread does not match this machine!

Another JohnS

[SpringbokParticipant @springbok]

I would love a CNC machine but as a pensioner cannot afford one anyone got one to give away…

Bob

[Jeff DaymanParticipant @jeffdayman43397]

John McNamara's router design does look like a great one and I agree would make a great article. However the construction methods re mortise/tenon/fasteners he describes are common industrial practice. I recall being shown fixtures made with that method around 28 years ago, and these fixtures had been designed and built some time before that.

I have found very little truly new under the sun in mechanical construction in 30 years professional experience except new manufacturing processes and new combinations of old methods.

JD

[David Clark 13Participant @davidclark13]

Hi Michael

No chance.

If it is not numbered in the magazine, it does not go into the digital issue.

That is why we can no longer do free plans.

If I don't number them in the magazine they won't be included.

Also, there is no budget for digital only articles.

Quite happy to start a digital CNC learning thread.

regards David

[Michael Cox 1Participant @michaelcox1]

David,

We already have an area where members of this forum can post photos. Could we not have an area where members can post files. Listings of CNC could be posted in that area by the author and he could then reference a link to the file in the article that appears in the magazine. This way the article in the mag in uncluttered by lengthy listings.

As a benefit to MyHobbyStore it might encourage non-subscription members to take out a subscription!

Mike

[John Stevenson 1Participant @johnstevenson1]

Posted by Springbok on 27/09/2012 19:27:04:

I would love a CNC machine but as a pensioner cannot afford one anyone got one to give away…

Bob

It's all a matter of priorities, if you want a cnc hard enough you make allowances. Don't bother building choo choo's and built a cnc.

However if Choo choo's interest you more then it shows where prioorities lie.

You could always build the wooden one that has just run in MEW, cheap but functional enough to learn.

John S.

[John McNamaraParticipant @johnmcnamara74883]

Hi All

I would like to see other joint designs or photos of the one I am using. I have seen the mortise and tenon used with laser cut work many times for alignment as well as strength, usually as a precursor to welding. I have not seen embedded fasteners used in this way.

And maybe there are other joining methods that have application to our work. Any joint that removes the need to weld with the subsequent distortion it causes.

Cheers

John

I have added another album. images from it below

Actual part (Bearing support foot) from the router, In this case the nut is embedded in the plate.
Also two CAD views showing fastenings in place with the bolt embedded in the plate.

—

—

—

Edited By John McNamara on 27/09/2012 23:09:44

[Michael GilliganParticipant @michaelgilligan61133]

John,

 

That does look very ingenious. I like the idea of flat-pack machines … even if the package weight may come as a shock!

 

By the way; you won't have seen it, but our TV programme "Grand Designs" recently featured a House built from Plywood Boxes that were CNC machined on Site. The "factory" was a shed, and all the material was delivered as 8'x4' sheets.

 

 

MichaelG.

 

I just found the website of Facit Homes … I think you will like the process.

Edited By Michael Gilligan on 27/09/2012 23:40:18

[VersabossParticipant @versaboss]

Posted by David Clark 1 on 27/09/2012 12:53:36:

Hi Hansrudolf

Whjat is wrong with Mick Knights articles?

regards David

Well, you asked… although I am not sure if it really needs an answer here. And the first – quite long – answer i erroneously deleted before posting it .

So the short version:

– M.K takes too many 180 degree turns in his ramblings. Well, paid by the page – perhaps I would do it also .

– Too many errors in an article for beginners. I wrote about this shortly after the first installment was published. The latest one: the milling cutter on page 17, MEW 195 is not TiAlN coated, but TiN (yellow). TiAlN is grey-blueish.

So what, you may say. Publishing erroneous information in a technical magazine is not a good thing, imho. Especially when it should address the beginners, it only promotes urban myths.

Sorry for stirring around in this again, but, as I said, i was asked…

Greetings, Hansrudolf

[Another JohnSParticipant @anotherjohns]

John – like others, congratulations on your work. First time I saw the bolt-in-t-slot construction, I thought it really interesting and a great idea.

I also like what I have seen of your design, so as they say "great minds think alike".

The "diylilcnc.org" has this type of joint (unless I'm mistaken) on their designs. I'll try and give a link to one of their pictures here. Please correct me if I am mistaken about the design.

Another JohnS.

[John McNamaraParticipant @johnmcnamara74883]

Hi John.

Yes and no……

The design does show the t slot however the two tenons are the key to my design. They offer huge lateral support removing all sheer from the threaded fastening, at the same time providing .01mm from the laser cutter (plus tolerance) location. a threaded fastener alone cannot do this.

Cheers

John

 

Edited By John McNamara on 28/09/2012 04:23:28

[Rod AshtonParticipant @rodashton53132]

David :-

"Also, there is no budget for digital only articles.

Quite happy to start a digital CNC learning thread."

Please do follow up as convenient. I firmly believe you would significantly increase subscription by publishing/posting articles and learning threads.

Bob :- I am a pensioner also ( not a rich one) I am a time served toolmaker (handraulic) and made a career in CAD tooling design, beginning in ACAD2 for reference. Just gone into CNC milling and turning. The most fascinating challenge I have approached in 20 years. Even if you cannot run to the hardware. A brief study of the concepts is inspiring.

If you find yourself in the central south and want to play with some machines. PM me and I will make a cup of cocoa (or Camp coffee if I have enough coupons.)

[John Stevenson 1Participant @johnstevenson1]

Posted by Rod Ashton on 28/09/2012 08:47:07:.

.

PM me and I will make a cup of Camp coffee if I have enough coupons.

Rod,

I think you have just blown any chance of any support given that last offer

Camp coffee ? my God that like drinking the hard shoulder on the M1, just south of Milton Keynes.

John S.

[mickParticipant @mick65121]

Hi. Hansrudolf.

I take comfort from knowing that you still find time to read my ramblings. Just a couple of things by way of defence and explanation. The reason I ramble on, is not for financial gain, although being retired it comes in useful, but to pass on what knowledge and experience I have gained from a working lifetime in mechanical engineering, hopefully in not too dry a way, which from the majority of feed back that reaches me, readers find useful. As for TiAIN appearing in the MEW next to the photos of milling cutters, there's no denying that it does, only on this occasion I didn't put it there.

Regards.

Mick

[Chris CourtneyParticipant @chriscourtney72250]

I like your design John McNamara, it is a good use of laser cutting. Your joint design is not original I'm afraid, here is an example of a 3D printer constructed from laser cut plywood which uses a joint of this type **LINK** I have been using this type of joint for laser cut components for a while now. I don't mean to detract from your work, I've loved your innovative approach in your posting on Epoxy concrete machines. I suspect that this joint has been independently developed by a number of people.

Chris

[David Clark 13Participant @davidclark13]

Hi Hans Rudolph.

I think the Tiain coating may have been my error.

The original was TiCN, clearly wrong,  and I changed it to TiAIN instead of TiN. by mistake.

Mick is dyslexic and sometimes errors creep in.

regards David

 

 

Edited By David Clark 1 on 28/09/2012 09:55:45

[Tony JeffreeParticipant @tonyjeffree56510]

Isn't the whole discussion of whether or not John M's jointing technique is new or old rather missing the point?

The important point (to me, at least) is that he is using techniques that I haven't seen described in MEW before, and seeing what he has done is already causing ideas to spark in my brain.

Laser cutting is getting more and more accessible to the model engineer – either as a bought-in service or if you want to go the whole hog, the entry price for a small laser cutter is comparable to that of a small CNC mill. Admittedly, you would pay more to buy a laser cutter capable of cutting sheet steel, but as demonstrated with the wooden CNC mill a couple of issues ago, there's a lot that can be done with other materials (wood, perspex…) as the starting point, and even a small laser cutter will handle those materials to a reasonable thickness. Combining the accuracy of laser cutting with the kind of easy-to-assemble jointing systems John M is using is very interesting. With free software available for CAD, the idea of shipping a set of drawings to your local friendly laser cutting house & getting back a kit of parts for your machine is very appealing indeed, and as John M indicates, the premium over the cost of material isn't outrageous either.

Regards,

Tony

[Chris CourtneyParticipant @chriscourtney72250]

I agree with you Tony, I only replied to John M about the joint because he specifically said he'd like to see other examples of that type of joint. The idea of providing dxf sets ready for laser cutting by your local laser cutting company has been gathering momentum in the Reprap community and the US Maker movement. It is great to see a solid looking design appearing in the model engineering community. As you say low power lasers capable of cutting acrylic, MDF and Plywood etc. are becoming much more affordable. Once you have a laser cutting system it is amazing the number of applications you find for it.

Chris

[David Clark 13Participant @davidclark13]

Hi Mick

I get a lor of people saying how they like your series.

You did get TiN wrong, it saysTiCN on the original which is why I altered it but I got it wrong as well.

I just searched for the right colour and it showed somewhere on the internet that TiAIN was gold.

Obviously wrong.

regards David

[mike mcdermidParticipant @mikemcdermid41977]

Posted by Tony Jeffree on 28/09/2012 10:10:10:

Isn't the whole discussion of whether or not John M's jointing technique is new or old rather missing the point?

The important point (to me, at least) is that he is using techniques that I haven't seen described in MEW before, and seeing what he has done is already causing ideas to spark in my brain.

Laser cutting is getting more and more accessible to the model engineer – either as a bought-in service or if you want to go the whole hog, the entry price for a small laser cutter is comparable to that of a small CNC mill. Admittedly, you would pay more to buy a laser cutter capable of cutting sheet steel, but as demonstrated with the wooden CNC mill a couple of issues ago, there's a lot that can be done with other materials (wood, perspex…) as the starting point, and even a small laser cutter will handle those materials to a reasonable thickness. Combining the accuracy of laser cutting with the kind of easy-to-assemble jointing systems John M is using is very interesting. With free software available for CAD, the idea of shipping a set of drawings to your local friendly laser cutting house & getting back a kit of parts for your machine is very appealing indeed, and as John M indicates, the premium over the cost of material isn't outrageous either.

Regards,

Tony

Sorry it might be my post that came across as not a new trick in the book,

not really ,my intention was to point out that a certain jet engine company are using the same jointing and construction method to make mich lighter jigs and fixtures , not made out of solid billets etc and are cheaper in the traditional toolmaking sense materials wise, these things are holding micron repeatability ,they have invested considerable amounts of money in proving this works and its used in production, its a very effective method

the sticky for me was when the development guy at RR was saying patent this that and blah blah and the two guys next to me pointed out this wasn't new and that several companies had done this before

those reprap or is it makerbot? also use this principle but this is the way things are headed lots of big companies do light tools (light on material costs or use, not lightweight materials)

I read an article once on a division master for thread cutting by the time I had thought it through a stepper ,driver and pc would do the same ,the PC is what im used to but i would do the division master experiment to learn something new

I suppose if you come from a world of CNC its nice to just use your brain and hand co-ordination on a manual machine ,if your coming at it as manual guy your also learning something new Folks not used to seeing a machine cut threads are often mouth agape when (tongue in cheak statement) they realise the machine does it all for you….

[John Stevenson 1Participant @johnstevenson1]

Playing devils advocate here.

I like John's idea, it stirs the grey cells up to allow you to think out the box, is it new ? No, similar has been done for years but is it new to the forum readers ? that's what matters.

In a conversation on the phone the other day with Tony we discussed a lot of this and the negative side of the conversation I have is cost. John has quoted material cost and material cost X 2 for labour.

Now working from the layout drawings that John put up and taking the stepper motor as a size 23 for scale I did a quick work out and that first full sheet alone would cost me about £240 and I have very good laser cutting contacts.

Now material costs would be about £30 for this sheet at bulk rates and so total cost based on Johns figures should be £90. There is a big discrepancy somewhere.

Laser cutting works on a material cost and cost per inch or millimetre the machine has to travel, they know these costs to a fine art. That's why when you send a job in for cutting they always program it up before they get the order so they know the price.

If you then price up the common extruded alloy that a lot of routers use this method becomes expensive, at least in the UK on our prices.

However now for the positive bit, anyone of a squeamish disposition as regards CNC need read no further, thank you for your time.

On the market in the UK are cheap plasma cutters that can be bought for around £200. They use single phase and compressed air, no expensive gases or rental bottles.

Do a search on Ebay in Industrial tools for Cut40, if you search by lowest first you will get some 2 pin plugs followed by the consumables, tips etc which are very, very cheap.

Now if you get your CNC, bolt a length of box section to the bed sticking our with the torch on the end, pack the sheet you want to cut so it's just touching and clear of the bed movement if follows that any moves the bed makes will be transmitted to the torch.

Remember those 2 pin plugs [ incidentally Maplins are cheaper ] if you wire a push button switch to a length of wire and plug into the plasma cutter.

Now put the switch onto the spindle so any programmed Z move makes contact.

Is the light coming on ?

So you program your part, allow for the cut width just as you would with a milling cutter.

Z comes down, hits the bed [ best to put a sheet over the tee slots or fasten a sheet to the top of the box section ] plasma fires up and it goes round and cuts your shape.

Quick, easy, low cost and an extra manufacturing technique at your finger tips.

Incorporate John's captive bolt system and tenons and you have yet another skill.

John S.

[John Stevenson 1Participant @johnstevenson1]

One other quick point.

On the designs I have seen the fastener design is reversed to Johns.

He has a hex head set screw fitted in the slot and a nut on the top. The ones I have seen have a deeper slot and the nut is held in the slot close to the bottom of the slot and a screw fitted from the top.

This makes more sense to me as it gives a choice of screws to be used, pan, posi, allen etc and neater at the top.

Plus hex headed set screws are not as easy to source as say allen or pan head and plain nuts.

Does the same job and if you want a locking design you can always use nyloc nuts in the slot.

John S.

[John McNamaraParticipant @johnmcnamara74883]

 

Hi ALL…. Hi John S

A pretty good day at the exhibition, the doors opened at 9:AM and it was very busy by 9:15 By 5:PM I was all talked out having had no break apart from a coffee and a sanga on the go.

Material costs?
The machine is made from 5mm steel plate. Depending on the source that costs about $160 for a 2400×1200 sheet Plus Vat (GST in Australia). Plus minimum delivery charges…..horrendous for one sheet

I have attached an image of the cutline and a rough nesting as drawn the area is about 1.5 x 1.1metres. There is also a small number of 2.5mm steel sheet parts about a quarter of a square metre. The laser cutter may re-nest the parts for a better yield. and no we did not ask for the off cuts.

I avoid providing material to laser cutters unless it is special alloy, if there is any trouble with warping it is the laser cutters responsibility if they use their sheet. (Subject to their terms, conditions and tolerances sheet). Anyway it was an excellent job well within spec.

The actual price paid was $450 Australian dollars for materials and labour. Hence my rough stab at some sort of back of the envelope pricing model. Material Plus material x 2 = labour. For light steel…. Because this thread is read from many countries, I guess actual pricing comparison is rather error prone. Hence my avoidance of actual pricing in the first instance.

Laser cutters charge in several ways… a setup charge nominally around 50 dollars if you give them a perfect file that does not need reworking, (we did provide a good file). Otherwise there is a hefty hourly rate for redrawing. On top of this is the cutting length, and in particular the number of holes pierced; the machine has to run slower. (on this job rather a lot). Yes they make a profit on the materials, they need it to pay for large increases in power and gas expenses and machines that cost more than the median house.

For more specialised work there are different gases, at somewhat extra cost. Nitrogen for instance if you want a bright edge, without the fine blue scale left by oxygen, Different gasses also can improve the quality of the edge. Worth discussing if you have a critical application. We just asked for "run of the mill".

The connection.
Depending on the location you will find you need: bolt head sitting proud on top, countersunk below the surface bolt head on top, so you can place something flat over it. and sometimes nut on top. They all work fine. High tensile bolts and nuts are a must to lessen the creep you get from common no name hardware fastenings. Good quality shake proof washers are always a good Idea and have been used throughout this project. Nylock nuts are fine although not so the cheap import type, many appear to be rather soft poor quality steel. Maybe permanent Loctite is also a good idea.

Anyway another big day tomorrow……..

Cheers

John

A added a couple of rough photos, Better ones tomorrow.

Edited By John McNamara on 29/09/2012 16:16:33

[Michael GilliganParticipant @michaelgilligan61133]

Well done John, it looks good

[and, nice to see someone found a Beer]

You mention permanent Loctite; so let me offer one suggestion … something we used very effectively on vibration test fixtures:

Use 638 or similar Loctite on the Mortice & Tenon joints, [don't waste it on the nuts & bolts] and you should achieve a "permanent" structure without needing to tighten the nuts & bolts too aggressively.

Although it's not stricly an adhesive; the joints you are using would respond very well, because the Loctite would be working in compression & shear … which is, of course, exactly what it's designed for.

MichaelG.

P.S.

Obviously you would only make some areas "permanent" … but I'm sure I don't need to tell you that.

[Rod AshtonParticipant @rodashton53132]

The thread has morphed away from the original question.

How then, about the future for further Mach3 articles!!!!

[Author]

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