#1
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Bought the Plans a couple of years ago - trying to start
Hi Everyone,
I bought the plans a couple of years ago,(Have the plans been updated since then?) but never did more than buy some of the steel. I am now interested in building a machine that is fast and similar to the ShopBot that a local High school has (actually 3 machines- a 4 foot and an 8 foot 'Bot + a legacy 3 x 4' bed with an A turning axis). I spent 3 days at the Legacy factory training on their machines. All great machines, but I know how much they cost! I think that I can build a machine like those, but for less money (which I have limited amounts of) using these plans and making modifications to suite my personal needs. I built a DIY machine from MDF and it works fine but is limited and I now have some products that I am selling and would like to increase productivity and accuracy. I am a retired (2003)Telecommunications/computer engineer and have been teaching computer related subjects at the local Junior College along with computer programming and business management stuff since then. I am fairly good at TurboCad in 2D and 3d and use Corel draw frequently. I got disgusted with the management at the schools and am now free to pursue my real interests without interference and have my wife's support (this is important) since she has seen what I can do with this technology, and would join me in a business venture like this (She is a CPA with PHD and MBA) so I want her in my company! She is also bogged down with the loser bureaucrats at a University and would like freedom as well. I have a BS degree in computer science/engineering and a Masters in Business and MIS. I have a small shop that I built a couple of years ago to work in with tools to do this. I used to own a small sheet metal shop so I do have some mechanical skills as well. I built all the electronics for my DIY machine and ordered cnc parts from Keling (now Automation Tech). My biggest fear is grinding the rails at this point. I have read all the posts, but still feel apprehensive and don't want to "screw it up." I have a Makita 6 amp grinder that I think will work for this, but not sure. I have a MIG welder, a metal band saw and lots of hand tool that I can use if needed. I think I have the mechanical skills at this point. My plan is to build a 4'x4' machine with an A axis for turning and maybe a rotational B and C added to the Z axis to cut compound angles (Dougherty Drive?), because of some furniture items I have on the drawing board. So, should I do it? Pease help me get started... And for the basic machine- what is the cost? Randall (Randy) in Colorado |
#2
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Look at my build, I bought pre-ground rails. They cost a little more but not that much. Since my build, others have built with pre-ground.
Good luck. |
#3
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I'll go look, Thanks.
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#4
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Randy,
I have a similar background and I built a machine. Took me about 4 months. My cost was about $4000. I found some used Oriental Motors steppers that saved me about $500. The plans have not change in the last two years, so your good to go with the plans that you have. I was worried about grinding the rails too. But I got the job done. You can look at my build for some pointers. Others have offered pointers too. I don't know the cost differential of grinding them yourself versus buying pre-ground rails. The skate has been redesigned since I ground mine. The old skate rode on two bolts that set the height. The re-designed skate rides on bearings. The only problem I had was that the bolts wore and changed the height of the cut without me making the change. I'm confident that the new design would resolve this issue. I was also able to find a good deal on a steel cutting circular saw. This allowed me to cut the rail stock to height very easily. Others make these cuts using cutting disks. If you decide to grind your own rails, pay attention to the pointers about using good quality thin cutting disks to cut your rail stock to height. |
#5
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Welcome back!
Don't be intimidated by the rail making. Its easier than it looks, its just tedious & dirty chore. BUT if you follow what we do, & take enough precautions (which already been highlighted in more builds than you care to read), it will over & done with in a few working days. |
#6
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Welcome.
Don't worry too much about the rail grinding, it is just dirty and noisy. Old clothes, gloves and ear/eye protection. I cut mine a few weeks ago using the old twin bolt skate design. My grinder was Maktec (cheap Makita), it still works. Read plenty and don't rush things. Mine moved for the first time today after nearly 5 weeks. Not sure mow many more months to go. Enjoy yourself |
#7
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Welcome. Just read and enjoy. If those rails bug you, start somewhere else and then come back to them one you hit a few milestones in your build.
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#8
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Thanks, I spent a lot of time reading and I really appreciate the help and effort that you are willing to share with me. I may try to find a steel cutting saw and cut them that way. I am also looking at the premade rails at the advice of you.
I guess the first step is to get going.... I just got caught up in the other things and this got back burnered. Thanks again. |
#9
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The rails are not a problem, just find a good support base to cut them, a 125mm disk instead of 115 helps a lot on the cutting. The grinding process with abrasive disks ( with grit 16 it's a very fast process) is so much easier then with grinding disks ... just try you will see it's not difficult at all ...
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#10
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Well I think an A axis for turning it a great idea and you can do many 3d's with it and many realized it .... but B an C (5 axis) although it's a fascinating idea it as never been realized I don't think it can be easily done with the mechmate unless you do heavy modifications the Z axis
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#11
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cutting the rails
I've found hardened rails for about $300 in the lengths I'm thinking about. I really like the idea of hardened steel for rails after reading this forum, and $300 seems small when looking at how much less I will pay for professional machine - and I am a kind of a overbuild sort.
I think I will still have to cut the angle down to the height needed anyway and then attach the hardened rails to that. I'm looking at buying a steel circular saw to do the cutting. I picked up some steel at a local salvage yard, but still need the main rails. I may need to travel to a bigger town to get exactly what I need (pueblo). I can't believe how much reading I'm having to do! It's like a Masters Degree+ but far more fulfilling. I get really excited when something works after I build it. It makes me feel so empowered (but not in the usual evil way) - Like a little kid and a new bike. Thanks again for help... This is not my first machine so that helps a lot. Two years ago this seemed overwhelming, now only seems like time, work and money. Randy |
#12
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Randy,
I used a steelmax (or similar) steel circular saw in constructing my table. It is a fairly ROUGH cutting tool, even with proper fixtures and cutting guides to keep all square. With that said, I did many trials on cutting rail height sections down with limited success on keeping the tolerance in check. The grinder with Cut off wheel is preferred. If you are going to use the hardened rail, then an aluminum support angle section works well due to the fact that the rail does NOT sit on the cut line, but on the native uncut metal. Details are in the plans. |
#13
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I used hardened v rails bolted to angle. Was a no-brainer for cost and longevity.
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#14
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Hi Randy. We were also afraid with grinding the rails. You said that you have a smaller CNC unit so i guess you can do what we did for grinding the rails. Just watch at this video.
http://www.youtube.com/watch?v=XExmmSlB2-E hope this can help!!!! |
#15
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Chicken or EGG
nice video and if I had my MM already completed I could do this. It does show how versatal the MM base is. Pete, how long do the ground angle iron rails last?
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#16
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Hurshy,
Depends on the usage. I remember seeing a few posts talking about making new rails. The rail grinding is not a hard process and it will last a long time. Many years in most cases. But there are a lot of factors that weigh into this are, including but not limited to weight of gantry, cutting in the same area a lot, accelerations, spring tensions, acceptable downtime, your time availability to make new, etc. I would prefer the rails harder than the wheels. I would rather the wheels wear out. Wheels are easy to replace, the rails takes more time. The downside is it takes a little more time and planning to implement a hardened V-rail system in the beginning. But to change out the rails on mine now if and when I have to change them is the time to remove and put back in the # of bolts on the rail in question. Not more than 15 minutes to replace all of rails on all of the axes. |
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