# First attempt at CAD and a engine design



## Metal Mickey (Dec 20, 2008)

Well in for a pound as they say.....after building the two wobbler's I started to think about an engine on the same principles but with two cylinders so it would self start (one hopes......(posh now I am using a computer)). I also am learning how to use BobCad Cad program.

So to recap, I am a novice engineer, a novice Cad user and a novice designer. Should be an interesting ride!

Anyway copyright accepted as the design will be worth a fortune...so its free if it works and for sale if it doesn't...Have I got that right? Anyway a few images to show where I am. Advice and constructive criticism welcome.












and where I am at the moment............


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## malcolmt (Dec 20, 2008)

Hi Mickey
You are a brave man, your skills on the BobCad look amazing to me, I am just starting off learning turbocad and its daunting. If i may offer what little advice i can it would be that in order to self start the crankpins need to be 270/90 degrees apart.
I am really looking forwards to following this one through with you. Good luck.

Kind regards

Malcolm


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## Brian Rupnow (Dec 20, 2008)

Mickey--Lookin good. Welcome to the wonderfull (and frustrating) world of 3D CAD. Malcom is correct about the offset of the crank pins for a self starter.---Brian


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## Brian Rupnow (Dec 21, 2008)

Mickey--A bit of information, if you didn't already know. The cylinders must be double acting in order for the engine to self start.--That is to say, they must not only receive steam on the stroke where the piston is moving away from the "dead end" of the cylinder, but must also receive steam (or air) on the return stroke.---Brian


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## BrianS (Dec 21, 2008)

Nice start with CAD. I have never used BobCAD but I've used AutoCAD for many years. If I may make a suggestion, you might want to make use of colors and make each part a different color. Also try to get in the habit of using different layers as well. They are a great help when the drawing starts getting complex.


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## Brian Rupnow (Dec 21, 2008)

It kind of looks as if he might have modelled the entire thing as one part----


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## Metal Mickey (Dec 21, 2008)

malcolmt  said:
			
		

> Hi Mickey
> 
> If i may offer what little advice i can it would be that in order to self start the crankpins need to be 270/90 degrees apart.
> 
> ...



See, you just prove the value of the forum. Thanks Malcolm and noted.



			
				Brian Rupnow  said:
			
		

> Mickey--A bit of information, if you didn't already know. The cylinders must be double acting in order for the engine to self start.--That is to say, they must not only receive steam on the stroke where the piston is moving away from the "dead end" of the cylinder, but must also receive steam (or air) on the return stroke.---Brian



Well that's a second point of vital information. This may need some thinking about.........It may not be a self starter in version 1 which would lead to development potential eh! (Another way of say bit off more than.....)



			
				BrianS  said:
			
		

> If I may make a suggestion, you might want to make use of colors and make each part a different color. Also try to get in the habit of using different layers as well. They are a great help when the drawing starts getting complex.



Thanks Brian. Another important and usefull lesson which I will put right..........I did however build the parts i.e. cylinders, pistons etc. on different layers. Don't ask me why I did but through good fortune now it seems I fluked that one! So its not modeled in one go. I don't think my brain could handle it in one piece!

I will now go back and look at the work again. I may decide its best to get 'something' from drawing board to running (a major achievement if I did) and leave self starting and feeding air both above and below the piston, till version 2 (or 3).

One thing you may assist me with is how to convert the 3D to line drawings? I have good training video's but there is just so much to learn! A hint would help....... but I have more to do before I need to do that.

Many thanks gents for good advice.

Metal Mickey....


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## Brian Rupnow (Dec 21, 2008)

Mick, in the software which I use, (Solidworks), there is no need to use layers. Layers is, I believe, more of a 2D Autocad thing. In my software, I drag and drop the solid model onto a pre formatted "Drawing sheet" and it automatically creates what views I ask it for. I'm not sure how you would do it. Does the program have a "Help" file associated with it?---Brian


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## Metal Mickey (Dec 21, 2008)

Brian Rupnow  said:
			
		

> in the software which I use, (Solidworks), there is no need to use layers. Layers is, I believe, more of a 2D Autocad thing. In my software, I drag and drop the solid model onto a pre formatted "Drawing sheet" and it automatically creates what views I ask it for. I'm not sure how you would do it. Does the program have a "Help" file associated with it?---Brian



Hello Brian, I will check. BobCad does have layers and I have just had a play with the colours as recommended and here is the updated image.






I will search now you have given me a lead...will let you know. It would be great if it worked like yours......

Mike


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## Metal Mickey (Dec 22, 2008)

Well I have decided it won't be self starting in version 1 (This one) but if it works I will use self starting as the reason for next development. Anyway I think theres enough here for comments before I do the line drawings. The only way I can see I can do them is in profile with just the outlines. Unless some one tells me different?

Anyway a couple of images. One with the transparent feature. I have added different colours and it does help so thanks for the idea.


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## 44-henry (Dec 29, 2008)

Your drawings look pretty good. I have had very little experience with Bobcad; however, I use AutoCAD 2008 all the time. In this program I typically work in 2D and 3D simaltaneously when I'm designing (or re-drawing) parts. 3D is quicker I think and I always seem to spend most of my time in the 2D side where the small details are what usually takes the extra time. In the end I try to blend the two together like the drawings that I have attached shows. The tap wrench is a project that I plan on using in a manufacturing processes class that I teach at the university where I work. The different colors are an image of the bone and charcoal color case hardening we do in our lab that I mapped onto the 3D object. 


View attachment Tap Wrench Page 1.pdf


View attachment Tap Wrench Page 2.pdf


View attachment Tap Wrench Page 3.pdf


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## Metal Mickey (Jan 23, 2009)

I haven't given up on the design and build of a wobbler as shown with the 3D drawings I produced via BobCad. However I have been giving a lot of thought about whether I really want to do CNC in the future and the answer has changed really, I don't want to pursue CNC in the immediate future.

So I have decided to sell the software package and training video set on eBay http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MESELX:IT&item=380099174505

I am going to build the engine drawn in 3D and then make a set of drawings from the build. Wrong way around I know but then that seems to be the best way froward for me. Time will tell as always.


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## Metal Mickey (Feb 20, 2009)

I should update you all as to where I am with my learning CAD and my own engine design. Not very far I have to say. 

I bought, at great expense, for me , BobCad CAD software. They seemed far more focused on selling than supporting as far as I was concerned and whilst I did like there 3D side it was transferring the models to 2D drawing sheets that I couldnt sort out. Without answering my many request and being fed up with the sales people who were told my views on support (they promised to pass on my remarks and help request) I could get no where. 

As someone once said if you keep banging your head against a wall you eventually find out that it hurts! In the end I took the salesmans advice when purchasing BobCad you could always sell it on eBay as its all yours (yes he did!) I did just that and listed it on eBay. I did not recover all my costs, but the biggest part, so looked for a cheap 2D drawing package. My confidence in software salesman taking a large knock I decided I would not go for such an expensive solution since I have cooled on the idea of CNC.

I saw a version of TurboCad 14 deluxe on eBay for under £30 so sent off for it straight away. When it arrived with a full training support CD system I thought it was a bargain. It would certainly do all the 2D stuff I wanted but it also does 3D. Whilst it is not as good as BobCad for 3D modeling it was only around a tenth of the price! So I then started to learn a whole new program. When it came to doing some of the tasks I wanted after becoming slightly more proficient, I discovered the natural limitations of the deluxe version. When searching out forums, the internet in general it seemed that upgrading it to a premium version was the way to go(where have I heard that before!) however I wasnt going to fork out several hundred pounds again but I found an American supplier of TurboCad version 12 premium for about a $100 or so and thats what I have now. I shall sell the version 14 deluxe soon so if anyones interested then email me.

I am now going to put all my efforts into learning how to use TurboCad 12 premium and have already produced some plans for small items in the workshop. At present I am working on a tool height setting fixture for setting the diameter of an in line boring tool (need it for the Seal build  link) based loosely on anothers design. A plan of the ball turning tool I made for the chess set featured in Model Engineer magazine (issues 4345, 4346 and 4347) to accompany a build article that may be published some time in the future. 

So you see the engine design is going to be later in the year before real progress is made. Indeed it may be a case of building parts, that will be drawn up later, and others that may be drawn first. Something I may not be alone in doingExperience and a better understanding of CAD may lead me away from this approach..time will as ever, tell!


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## Maryak (Feb 20, 2009)

Mike,

I have TC14 deluxe and I understand your frustration on both its' 3D capability and the price to upgrade. I am trying Alibre design which I downloaded free and eventually I hope to nail the 3D demon and find a use for both.

Good luck with your CAD - Once I got the hang of it I found TC to be a very good 2D program.

Best Regards
Bob.


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## Metal Mickey (Feb 20, 2009)

Bob, I tried to download Alibre some time ago but failed miserably. Does the free version allow you to dump the 3D work into a 2D or engineers plan format? Mike


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## stevehuckss396 (Feb 20, 2009)

Metal Mickey  said:
			
		

> Bob, I tried to download Alibre some time ago but failed miserably. Does the free version allow you to dump the 3D work into a 2D or engineers plan format? Mike



Hi Mickey!

All of the work that i sent you for the Seal camshaft was done in Alibre including the 2D drawings. I have been using the free version for about a year. If i ever hit the lottery, I would buy the big money version. It works very well.


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## Metal Mickey (Feb 20, 2009)

stevehuckss396  said:
			
		

> Hi Mickey!
> 
> All of the work that i sent you for the Seal camshaft was done in Alibre including the 2D drawings. I have been using the free version for about a year. If i ever hit the lottery, I would buy the big money version. It works very well.



Oh dear Steve, youv'e now given me a problem! What to do, what to do? I may give Alibre one more go before I decide to stick with one and at least learn the basics......some of the BobCad work has transferred across so its not a total loss but stickability needs to happen soon..........One more go..........


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## NickG (Feb 20, 2009)

Alibre is fantastic although the free version is quite limited. I would love the full version but just can't justify the price.

Nick


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## putputman (Feb 20, 2009)

Question for some of you that are using Alibre????

I have been using 2D for some years, but never tried 3D. I have recently downloaded the free version of Alibre. You get a full blown version for 30 days and then either have to purchase it or loose it and end up with the limited free version. I have no intention of ever purchasing an upgrade & have made that clear to the salesman.

I have been struggling with it, (haven't even completed the first exercise after several tries), and am wondering if it is worth the time and effort to learn this program based on the limited free version. Can the free version be useful in model making? I had hope I could make simple assemblies to show fits and interferences with this program.

Another question: Are there tutorials in the free version or do you have to master the program in the first 30 days.


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## stevehuckss396 (Feb 20, 2009)

I have been using the free version for a while. I have designed 2 engines from scratch. One being the Co2 V8 from last month and the other was a cox .049 based 9 cylinder radial.

The current Peewee project was drawn because i could'nt make sense of some of the numbers on the drawings. After drawing the parts I found some interference errors regarding the block and crankshaft. They were easily fixed before the first chip was made.

I would consider the time spent "worth it"


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## stevehuckss396 (Feb 20, 2009)

putputman  said:
			
		

> Question for some of you that are using Alibre????
> 
> I have been using 2D for some years, but never tried 3D.



That is going to bite you in the a$$. I had a hard time going from 2D to 3D because you need to think completely different. If you stick with it and get used to it, i doubt you will regret it.

I am not the greatest at 3D cad but I am willing to try to answer some questions if you would like some help.


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## Metal Mickey (Feb 21, 2009)

Bob, I downloaded Alibre last night without a hitch this time. One result though is the first attempt seems to have registered my free 30 days so this download has only allowed me the free version. I don't see that as a problem really as I won;t get disappointed with things that will be taken away! I'll only know the free version.



			
				putputman  said:
			
		

> Question for some of you that are using Alibre????
> 
> 
> Another question: Are there tutorials in the free version or do you have to master the program in the first 30 days.



Putputman I can set to tutorials through help and they are very good in my opinion. Certainly good enough to get going. Its early days for me (only about an hour playing) but it does seem a lot better than I thought but that may have been coloured with the download problems last time. I think I shall give it go for a while and put the turbocad on hold. So thanks for the nudge Steve. If you designed your engines on the free version then that's as much as I could want so I may have at last found the answer...bit I thought that before.............

Steve, one question....can you animate the free version? Bit much to ask I suppose...and I will be asking questions so you have been warned (although your also to blame so that will teach you!)


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## stevehuckss396 (Feb 21, 2009)

I dont believe you can animate. 

One other thing to think about. When you start putting things together in an assembly, you can only put 10 pieces together and save the assembly. My heads are one assembly and the block is one assembly ect. 

For the head, the 4 rocker arms in that assembly count as one part. the 4 valves count as one part ect. You can assemble 100 parts but you wont be able to save the assembly. Get used to making assemblys and it only takes a few minutes to load all the assemblys and put them together.


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## steamer (Feb 22, 2009)

I have a seat of Alibre and really Love it.

Steve is right though, you have to start thinking 3D and that was really hard for me as I started life out on the boards, then 2D CAD. Even today, if I am concepting something I often use crap o cad to start with just to make sure. Once over the hump, it gets a lot easier. I have found that Windows Vista and Alibre don't always appreciate eachother, but they seem to be Vista problems and minor and I seem to have worked around some of those short commings anyway.

Even full up, the price is very attractive considering the competition pricing.....but lets not go there again OK......

If you have some specific questions, I too would be glad to give some pointers.....

Dave


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## stevehuckss396 (Feb 22, 2009)

steamer  said:
			
		

> If you have some specific questions, I too would be glad to give some pointers.....



I would also be willing to give some help. I have done alot of the most basic stuff and some advanced stuff like cutting threads. I went over a friends house to help him along and brought home a few things. It's an oppertunity for everybody to learn something.


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## Metal Mickey (Feb 22, 2009)

Thanks Dave and Steve, much appreciated. Not being an engineer by trade or a draughsman so 2D knowledge is just as poor as 3D. I did get on with BobCad in 3D better than Turbo in 2D for the same time on each, so perhaps I have an advantage in not knowing enough about 2D. Its about time knowing little gives an advantage! :big:


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## NickG (Feb 22, 2009)

Damn it, when will I learn, that is so annoying when you've just spent a while typing a reply and the computer decides to lock up! :'( :'( :'(

Anyway, most of what I said was probably waffle!

My main points were:

 - 3D CAD is definitely the way to go.

 - Alibre is good, we use Unigraphics, a leader, if not the leader in 3D CAD and Alibre seems to me to have similar functionality and it's more user friendly, easy to pick up.

 - Main limitation of free version is number of parts in assembly. As Steve says, once you've mastered assembling stuff, you can build sub assemblies and soon put them all together to give you the picture of the completed model. However, as this can't be saved, you won't be able to produce a general assembly drawing of it, just individual parts or sub-assemblies.

 - Another limitation is not being able to produce sectioned views ... this is disabled. As model engineers we can probably work around this in most cases.

 - A good reason for assembling the whole thing is, if you assemble with the correct mating conditions, in turn giving components the correct degrees of freedom, you can "move" a part, i.e. you can spin the flywheel around and see all the rest of the engine working. As Steve, said, not sure if you can get it to do this automatically and run in a loop, but you can see what clearances / interference you have etc.

On my Stirling Engine below I inititally had interference between the con rod and cylinder wall, so I lengthened the condrod and other appropriate dimensions until it cleared.

Also attached is a general assembly drawing of my oscillating engine to give an example of a 2D drawing created from the 3D model.

It may sound like a long way around to create everything in 3D first, but trust me, once you get the hang of it (and it's not that hard) it's much better.

Nick


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## Metal Mickey (Mar 10, 2009)

Thanks Nick G. I have just done my first CAD project, a tool setting fixture for an inline boring bar (seperate thread just made) and used Alibre for it. Transfering the 3D model and getting plans out is brilliant (well to a newcomer). I am impressed and only wish I did not have the initial download problems which put me off the program initially. However since this one is free, I am converted!

Still much to learn but it is nice to be able to complete a project even if its a small one. Helps to build confidence.


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## NickG (Mar 10, 2009)

Mike,

No problem, I'm glad you've taken to the idea of 3D CAD. Well done with the setting fixture. Like anything, the more you use it the easier it gets and with this you will soon realise it's much easier and faster to produce and modify complex drawings.

Nick


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## Metal Mickey (Apr 9, 2009)

Alibre lives ......and is good.....

I must admit I have not progressed the engine design as stated in the heading to this post but I have finally settled (for how long I do not know) on Alibre because its cheap (FREE), it had 3D and can transfer a model to drawings very simply indeed.

I know there are limitations with the free version but I doubt I will be pushing at those boundries just yet. To show what I have done in practice here is a outline frame for a ball turning tool exported to a jpeg.....






I'm sold on Alibre and am in danger of becoming a fan! Look out........................


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## Maryak (Apr 9, 2009)

MM,

Your way ahead of me with Alibre. :bow:

I can't seem to find much time and I'm too impatient.

Best Regards
Bob


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## Brian Rupnow (Apr 9, 2009)

Metal Mickey---When you get real good at Alibre, come on over to my house and I'll let you use my Solidworks-- ;D ;D ;D---Brian


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## Metal Mickey (Apr 9, 2009)

Brian Rupnow  said:
			
		

> Metal Mickey---When you get real good at Alibre, come on over to my house and I'll let you use my Solidworks-- ;D ;D ;D---Brian



Brian I would love to be able to travel to come to your house. I can send the wife though............as long as you don't send her back! I don't think I could ever get to your level of knowledge and from what I hear the price of solid works would require me to own several banks (oh forget that, banks have lost us all our money!)

I would love to see people like yourself at work in real time. It takes me forever to do simple things. How many hours/days or in your case minutes, did it take you to do the image in your post!

I am an admirer of your work (and your speed of making what you design).

Bob, you old smoothy you! Your taking the Mickey (sorry) but thank you. I only posted to show that Alibre £ for £ is value for money really.


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## Brian Rupnow (Apr 9, 2009)

Metal Mickey--I have approximately 180 hours in what you see.--Figure about four and a half weeks of 8 hour days. I just queried my "Assembly statistics" and it informs me that there are 537 parts, which are combined into 44 sub assemblies and 2 master assemblies. And there are approximately 85 engineering shop drawings with complete bills of material. The speed that I work at is absolutely phenomenal.--No, really--it boggles my mind. After working on a drafting board for 33 years, and Autocad 2D for 2 years, and now 3D CAD for 9 years, I simply can not believe how fast this stuff is. Please don't send your wife--she is probably a lovely woman, but I'm not man enough to handle 2.----Brian


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## kvom (Apr 9, 2009)

Somewhat OT, but I am wondering if it would speed the process of learning one of the these programs by creating the parts from an existing 2D plan. Then when you convert back to 2D you could check if you did it correctly.


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## mu38&Bg# (Apr 20, 2009)

That is an easy way to learn a CAD program. If you are trying to learn design and CAD at the same time, that would be tough. Learning a CAD program isn't about making sure you've drawn the parts correctly, however. Learning A cad program is about how to use the user interface, the drawing tools, understanding what input give the appropriate result, organizing your steps to allow easy modification of the parts, etc. Anyone can learn 3D CAD today. Learning to use it effectively and efficiently is the challenge.

In Brian's design above it is possible to design it in Solidworks such that if there were models of the machine that were for instance, wider, entering the width in one place would update all parts that needed it, adjust number of fasteners if needed, update the drawings, etc. A design like that needs to planned in advance and you really need to understand how the program works.


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## Brian Rupnow (Apr 21, 2009)

Kvom--Working in 3D is very similar to working in 2D. In fact, when I design a part, I start with a sketch which is a 2D sketch consisting of standard construction geometry.---Lines, arcs, circles, etc. Once I have tailered that 2D sketch to be dimensionally correct, as I want it, I simply select the "extrude" icon and type in the depth that I want the part extruded to, and Bingo---the program creates a 3D part from my 2D sketch, extruded to the depth in the "Third Dimension" that I have put in a value for. Thats it!!! Likewise, if I want to create a cut away portion of an existing 3D part, all I do is select the face I want to draw on, select an icon that turns that face "square" to the computer screen, and start a sketch on that face. After I have created a 2D sketch on that face and dimensioned it to what I want it to be, I select the "cut" icon, and select whether I want the cut to be completely "through all" or if I only want to run the cut in a specified depth. Then I type in a value for the depth I want the cut to be, and it cuts the solid away, in the shape of the 2D sketch I created, to the depth I have typed in. Deiselpilot is talking about "Design Tables" whereby I can set up a solid part, even an assembly in a manner such that by changing one key figure, everything associated with that figure will change and update automatically.---And if I have previously created drawings of the part or assembly, the drawings will all update and the dimensions will all change automatically.


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## Metal Mickey (May 6, 2009)

Whilst I haven't added much to this thread I have been learning Alibre and I must say its a very good program. I am invloved in building my own saw table at the moment and made the images below in about 20 minutes which for me is good. The advantage with Alibre though is I can publish the work as Jpeg,bitmap,PDF and save as dxf files with the ability to produce 2D rawings very easily. I am no where like Brian and never will be but for my small needs this seems to be the answer.....


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## stevehuckss396 (May 6, 2009)

Metal Mickey  said:
			
		

> I am no where like Brian and never will be but for my small needs this seems to be the answer.....



Once you learn to put parts together in an assembly you will be just like him. It's like eating an elephant Mickey, one bite at a time!


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## Metal Mickey (May 7, 2009)

Yes Steve, that's the next challenge, fitting the parts together....as you say, one bight at a time....


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## cfellows (May 12, 2009)

I see you've mastered the "sweep cut" in Alibre. At least I think that's what the round belt grove is called. I have to figure that one out next.

Chuck


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## Maryak (May 13, 2009)

Great Progress Mike,

Hope you don't end up too much of a CAD. : :big: :big:

Best Regards
Bob


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## Metal Mickey (May 14, 2009)

Maryak  said:
			
		

> Great Progress Mike,
> 
> Hope you don't end up too much of a CAD. : :big: :big:
> 
> ...



You been talking to she who must be obeyed again Bob!



			
				cfellows  said:
			
		

> I see you've mastered the "sweep cut" in Alibre. At least I think that's what the round belt grove is called. I have to figure that one out next.
> 
> Chuck



Hello Chuck, I don't know if I did it the right way but I made the pulley as a line drawing then revolved it around the base line.


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## Metal Mickey (Aug 19, 2009)

For those who may be interested Alibre via the UK are selling the full version for a staggering £88 + vat a substantial saving indeed and I have just purchased it. If you want a good 3D package then just ask Steve Huck what he thinks. Its a bargain but be quick only 3 days left!

MM


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## Maryak (Aug 19, 2009)

Hey Mickey,

Welcome back, been on holidays ??? Hope everything is OK.

Best Regards
Bob


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## NickG (Aug 20, 2009)

I bought it the other day, worked out at £63.08 with the exchange rate. Amazing deal.

Nick


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## Metal Mickey (Aug 21, 2009)

Hello Bob, not been too good a year but hope the next part is better. Thanks for asking though. There is so much to catch up on.....so bear with me. MM


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