Last few days, I have been dilling, taping the 152 holes in the aluminum that will hold the rails and the rails. Things are moving at a slower pace but things are moving forward.

More pictures soon.

Tapping holes in alu is a pleasure with a cordless drill and some kerosene [paraffin] :)

Gerald,

Taped the rails not the Aluminum.

I used both the sprial taps with a drill and hand tap. I broke the tip off the hand tape and I was able to get it out and taped the hole also.

I am learning a lot building this machine.

Gerald,

Here are some pictures.... But the rails are tight against the aluminum.

If you want additional pictures or a different view, let me know. The close ups I took are a bit fuzzie, I will retake.

Thanks for the pics. So, do the rails fit snugly into the corner of the alu?

Gerald,

Yes they fit tight. I will try and get you a close up of the end corner view on Saturday.

Nils,
The pictures look great. It looks like you needed two pieces of rail. What was the max length of rail you can get and what length of table are you using. The transition from one to the next looks really good. I am really eager to see what you think of the whole bolt on rail method once your machine is up and cutting. (As are a lot of others too I think)

The rail sections are 6' long, thus we used 2 sections.
We have offset them slightly to each other so no 2 rollers can ever occupy a joint line at the same time.
This was easier on the Y-axis - we were able to use a 3' and 4' and offset the joint lines as well.
I was concerned that I might have to root pass weld the vee-rail for alignment, but the alum angle did a fine job. It fits VERY nicely on the inside of the extrusion.
This solution works very well - so far. The proof will be in the finished machine. But I will admit, those superior bearing rails sure are nice :)

Heath,

It took me about 3-4 days to tap and drill holes in the rails and the aluminum. If I would have been more careful in my transfer and hole drilling of the aluminum, it may have taken a day less. The one thing that I didn't have to deal with is the grinding dust.

I hope that when I finish that we will be able to compare the performance of the two machines since they are with in 10' of each other.

It is great having Sean and his machine to give me guidance.

This week I finally got my 20 rails (total length 60meters [200 ft]) done for 5 MM's. I will be the first to agree that those V-Strip rails on alu look VERY attractive. It might be a slow process, but it is controllable and predictable. The cutting and grinding of angle iron is economical, but hot rolled iron doesn't give you a nice accurate line to work from.

Hello All,

I realize this is not within the original design, but I received this tech alert from GlobeSpec while on vacation and just opened it yesterday. BishopWisecarver has just released a cap that fits in standard 40mm aluminium extrusion and accepts their size #3 90 deg rail, the product is called QuickTrak.

The link is here http://www.bwc.com/products/quicktrak.html, this of course opens up a whole new can of worms for constructing the frame from extruded aluminium profiles, but also provides a very convenient means of mounting dual rails at a fixed distance while providing a ready made recess for bolt heads to secure the entire assembly to any welded or flat angle frame.
http://www.bwc.com/product_photo.php?product=35

I haven't checked the CAD profile yet, but it looks like there may even be space to mount a narrow rack (8 - 10mm) directly on the extrusion beside the QuickTrak retainer.

Just something new to consider ... it (extrusion bolt-up) would certainly bring the possibility of building a machine within the reach of folks who don't necessarily have access to the tooling or skills to construct the railing system and frame using the conventional means discussed so far!

Gerald,
I had one question on the alu/capped rail solution. Since the rail sits beside the alu andle, is there any need to adjust the width of the gantry or spacing of the rails that is different than the ground rail solution. I have looked over the plans repeatedly, but cant seem to find any reference to any dimensional differences due to this offset?

I wish BWC would draw rollers and a car riding on that track.....the overhang on the roller mountings would be quite a lot. (longish cantilever shaft with the roller at the end).

Heath, that falls within the M12 "thin" nut and M12 shim washers mentioned on M1 20 100 A. You might be able to use a "full" nut instead of a thin nut.

(I see that drawing does show the V-Cap on alu at top right)

Gerald,
Thanks, that was the part I was missing. Geez, think I could find that last night looking for it? I knew it was there somewhere. :)

V-Cap rail screw spacing
 

Hi MM community,
A big Thank you to everyone for giving me something to do everyday last past few weeks. Reading this forum became absolutely obsessive.
i wanted to upload what i call "completed mechanical stage". It is time for me to worry about electrical. I still have no clue after reading every single thread on the subject. I am very worried but i am sure I'll get there eventually.
I will update with my progress.
Cheers!

. . . . The only thing that worries me a little is spacing of the screws for the thin V-rails. I think it should be less than 100mm.

Gerald,
Space is 200 bet M6 screws on the v-rail. I will remember your warning and keep an eye and it. I will go back to the drill as much as necessary.

Fred, that spacing is okay for carrying the mass of the parts vertically downwards. However, the forces at the cutter are mainly horizontal, and wheels also experience quite a bit of horizontal pushing and pulling. My concern is when a wheel is between 2 screws and it has a sideways load of maybe 20 to 30 kg. The thin rail will not get a permanent bend, but it may have a vibration or resonance. Anyway, you are aware of it now and will be watching for it. Let's hope that it is going to work for you and need no more screws. :)

Are there any concerns about the aluminum sagging under the weight of the gantry? As I understand it, the aluminum arch. angle is bearing the full weight of the gantry, where it goes beyond the supporting steel. For those that are more aware of relative strengths of materials, should we be concerned about any sagging, or is it over such a short distance that any movement would be negligible at best?

The overhang of the alu rail past the steel beam is very short and there are no concerns of it bending over such a short distance.

Alright, that's kind of what I figured, but wanted to confirm before I went ahead and settled on that design.

Btw, been a long-time lurker on here, will be getting started in my build, if all goes well, within the next month. Thanks for all the information and hard work you've put into this.

Eric,

I have aluminum rails and they work fine. You will not have any problem.

What I would like to ask is why we have to use the size 3 v-cap's? I personally want the v-caps for the hardening and the easy of changing them out if they should get worn out. But I really do not wan to use the aluminum as the rail base for installing them. The inner radius is a problem with the steel angle. but the the size 2 rails are used,... the steel angle can be easily used. Dim B = .250" which is pretty much the width of the garage ground steel angle. Except the v-cap is hardened. From the pics the v-bearings arent even using the entire rail surface anyways. So whats the deal with having to use size 3?

Also,... do the shims remain at S1 during the use of the machine? Or are they only used for leveling and after the v-cap bolts are tightened they are removed?

See post #59 above.

Ok. But im sure it would be fine if bolt spacing was close enough. Some of the bolt spacing I have seen in some of these pics is kind of scary:(

I think this is how Im going to go about it. A 3/16" x 2" iron flat bar to hang the rack and 2" x 2" x 1/8" angle iron to hold the V-Track vertical. The V-Track hangs on the side of the angle iron without the radius. Together they will hold up the gantry nicely. It looks pretty this wat too:) Both will have the same .5" mounting holes for adjustment. And the proxy holes too. Would I have to drill the proxy holes through both or just the angle? I dont even know how the proxies work yet,...

Charles,

Why don't you want to use the aluminum?

It just doesnt feel right to me:confused: I mean, we're constucting these machines that weigh nearly a ton out of steel and here are my rails or rail bases made of aluminum. It's just not sitting with me well. Im pretty sure this is what everyone is thinking that doesnt want to use aluminum.

Initially I was just going to grind my own rails out of angle iron. But I was worrying about them wearing down. I REALLY dont feel like changing them out any time soon. I read gerald's story about the height of the rails being 28mm. He said he was changing out his rails. Then was forced to use the hardened rails. This made me nervous. because he was changing out his rails probably because they got worn down.

I know he used his machine as a work horse,... but so will i. Im not using mine as a hobbist. My machine will be running almost everyday and all day. With the money I have allocted for this machine I will buy another laser/bent kit for another machine. I need this machine to be bullet proof. I need it to hold it's shape.

The method I have proposed will cost just about the same but will be stronger, look better,... it will be a little bit more work but im fine with that. And most importantly,... my gut is ok with it. I will report my results of course;)

Here's my approach. I think I will do it because theres no reason it wont work.

This is all steel we're looking at. There's a 1/8" thick base to hold up the rack. Then a 3/16" angle to hold the v-track. The rack is mounted to the 1/8" thick base using countersunk screws, 15 8-32's along the length of the rack in 8.25" intervals. No tape,... even though I didnt really have a problem with the tape. I did the screws because it works:) The holes in the rack do not pass completely through, .375". There is a very good reference surface forthe v-track too seeing there is no radius on the side in which its to be installed. I like it.

:confused::confused:

I have never replaced (changed out) rails and I have never used hardened rails for the x and y axes. You may be confusing something I said about the old ShopBot z-axis that wore out.

I suspect that if you did the calcs, you are going to find that a sandwich of 1/8" steel and 3/16" steel might be more flexible than 1/4" aluminium. I don't think you have an appreciation for how flimsy your individual components are . . . . . pick up a length of any of those in the middle and watch the ends droop probably 6" or so. You might also see the thin stuff bow up between your fixing screws.

Oh maybe your right about the rail changing being for the shopbot. But isnt a rail a rail?

Well,... I would still like to try this. If I fail I fail but I have to try. I have a feeling it would work good. If it does not I will report back. So that others may avoid it.

Thanks GD.

Charles,
Yes, a rail is a rail, a tire is a tire, ac car is a car... etc some tire last longer on the same car, some cars out perform others & some cheap crappy looking rails last longer in a mysterious way ;)

I wish I don't have to come to this but I do suggest you focus on building & leave the design part out if your goal is "to build a MecaMate.... ". Do the mod/upgrade on your 2nd MM (since your ARE building a 2nd one)

MM is a good proven design; Radical in some way & using "crappy" components freely (which IMHO the beauty of it)... BUT don't judge the book by the cover, build & operate one before you pass any judgment... Even though my MM is still in the building process, I learn to appreciate the design ever more as the machine takes shape.

Some how, you got to trust somebody, some time...

I sound like leaking up to Gerald, but I'm not, its a fine line between appreciation & idol-ism.

Hope this help.

The rail changing was only ever for a ShopBot Z-axis, which is quite different to the x and y axes. So, a rail isn't a rail.

Ok. That I understand. Thats why you recommend the hardened ground plate to be used for mounting/ rails for the z-axis.

I am a very stuborn person. I am going to try this regardless. Its human nature. It would only be a small price to pay if it failed. More of an annoyance really.

Everything else im ok with. It "feels" right. Dont really plan on changing anything else. Just this. Which isnt to far off from the plans.

I dont mean to offend by the change. I do have faith in GD. But this "feeling" of mine is what I call a sickness. even if I did the aluminum angle. After the machine was built and running. I wouldnt make it to my next machine but trying this. Because the idea eats at me.

Anyways. Just a quick question though. the angle iron im using is 3/16" thick. Thats only .0625" smaller. And it doesnt hang off the main beams as much as the one in the plans. My track is hanging from an 1/8" flat bar with 15 bolts holding it in place. It has to support the up force of the motor on the spring. No big deal. It extends out as far as the rails do in the plans. It also helps to support the bottom of the angle iron. I really feel this is rock solid.

You say that along they are weak and flimsy if I hold them at center the ends to sag. Again the angle iron isnt to far off from the rail in the plans. And I will have 15 bolts hold all that together. More if needed. I just dont see this as being a total failure.

Thanks for the input.

Some how that sounded really familiar.... I feel a kin to you now...;)

Anyway, if that can put your mind to peace, give it a shot.

BTW, Having worked with steel long enough in my day job, I recon 1/8" flat bar IS flimsy & will not give you the flat you are looking for, you may (only may, no promises) have better luck with milled 25mm/1" thk high carbon steel. BUT I leave it to your own digression.

A side note, I taped my Y-rack onto the gantry rails last night & the 1mm the double sided tape filled the gaps as expected & held up beautifully. No sign of the problem that worries you so much ;)
Attachment 8838

Excellent. I feel better now that someone really understands where im coming from. As you said Im really doing it to ease my mind.

I really dont mind the tape all that much. I still might go ahead and use it. But I would erally like to try mounting the rack the way I showed. tapered bolts throughout the length of the rack. Non-penetrating holes. Why? because the setup is almost perfect. Atleast in my opinion.

You are right, 1/8" flat bar steel is pretty flimsy on its own. But I think with the way im going to mount it it will be ok. What forces do you think it will be subject to other than the weight of the rack, the upward force of the motor on a spring, and the back and forth x axis movement?

I could even drill and tap the angle underneath and bolt the 1/8" to the angle too. I really think this is doable one way or another. I might even add more bolts for mounting the angle and flat bar and the rack. I'll make it work.

Im really looking forward to starting my build. Im waiting for my funds to show up in my bank account:) right now im working on my garage getting it ready for this beast.

You will be amaze how easy it is to tape the rack on. It is the perfect way for a lazy person like myself. :D

Anyway, I think we have a lot in common, I was waiting for fund to come in from some jobs I did earlier since July 09 & didn't have any work space until mid-Nov09. BUT I did what I could & do every bit of the work whenever I can by small purchases, doing leg works for better deal & sourcing equivalant spec items. If I were to wait for enough fund to do all the purchase I don't think the build would even take off in the first place.

My original intention was pre-ground rails, but the $$$ in flux wasn't that fast & shy in volum. I scraped around hard enough to come up with the money to buy the steel & started grinding the rails while waiting for the money & before I know it, the rails are completed & the table erected while the $$$ only trickled in slowly & other commitments are draining them quickly... :mad:

Well... I guess the only other way out other then saving up more fund is to make more money...

Well,.. we do have a lot in common:) I didnt have any space for a machine like this until now. I recently bought a house with girlfriend. I made sure it had a huge garage. I have a huge 3 car garage with an upstairs loft. totally empty and ready to be filed:) I have to finish the inside though. No insulation or sheetrock. Hot during the sumer and cold during the winter. Im doing this all now. I was actually posting here a while ago saying i was purchasing a home etc etc. Hoping atleast. Well we got exactly what we wanted.

With the purchase of our home we get an $8000 incentive. Well atleast I do because its my first home. With some other money we paid toward the house Im getting back 10000. I will be able to purchase everything up front. If it wasnt for this I would be in your shoes. Saving slowly do what I can. Which im fine with because that all i know. I am very fortunate to be in the position I am now. For once atleast. Bummer thing though is that it could take up to 20 weeks to get my return:( So while I wait I will continue working on the garage and going through the mm plans building my machine on my pc.

I am hoping that when im good enough with my router I will be able to make money with it to build another machine. and keep moving forward.

about the 1/8" flat bar being flimsy. If you hold it at the center of its length,... yes it will bow down. But if you hold it at the center of it's width,... that should be enuogh to hold the rack and deal with any forces. Same goes for the angle iron. The center of its width is what we worrying about with the rails.

Oh and should you hve painted your machine before sticking the rack to the rail? or should the tape be stuck to bare clean metal?