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Gerald_D
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Username: Gerald_d
Post Number: 435
Registered: 11-2005
| | Posted on Monday, November 13, 2006 - 06:37 pm: | 
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Open thread for collecting posts from other threads.....
By fabrica on Tuesday, November 07, 2006 - 03:17 am:
Gerald What do you think of the Yitong offer which I have copied above. They have agreed to do the Rail as well. Maybe we could get them to do a rail as per Mechmate specs and get them to offer our guys a special price. If you are agreeable to this you could post the specs on this thread so that I could immedietly convey them to the manufacturer and get them to quote a price.
By vadeem on Tuesday, November 07, 2006 - 04:11 am:
How would we safely ship 10 or 12 foot rails?
By fabrica on Tuesday, November 07, 2006 - 04:21 am:
To ship rails safely wood crates should do a good job. I am waiting for Gerald to give me the specs so that I could have a serious discussion with the Yitong guy. |
Gerald_D
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Username: Gerald_d
Post Number: 391
Registered: 11-2005
| | Posted on Tuesday, November 07, 2006 - 07:17 am: |
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The rail specs are on drawing number M1 10 110 M that you have downloaded. You are welcome to send the drawings out to suppliers and to arrange "group buys". When the discussions get a little too commercial, then I will make a "market" section in this Forum where people can do limited advertising.
For shipping rails, what about strapping them to each other in pairs with wood in between....
.....and then putting them inside cheap round plastic pipes....? (The ends are most likely to get damaged - that is one of the reasons the drawing shows an extra 100mm to be trimmed after assembly)
PS. if you publish someone's e-mail, please be sure that they won't mind. |
fabrica
Registered
Username: Daya
Post Number: 21
Registered: 10-2006
| | Posted on Wednesday, November 08, 2006 - 04:45 pm: |
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Yitong guys have replied to me saying that they could do the rails as per our specs which I sent to them. I also informed them that we are a group who are willing to buy from them. They need to know the yearly sales they could expect of Rollers and rails. How should we respond. |
fabrica
Registered
Username: Daya
Post Number: 22
Registered: 10-2006
| | Posted on Wednesday, November 08, 2006 - 05:25 pm: |
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Below given is a link to a interesting site of a manufacturer of linear motion products.
http://www.lm76.com |
Gerald_D
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Username: Gerald_d
Post Number: 404
Registered: 11-2005
| | Posted on Wednesday, November 08, 2006 - 06:57 pm: |
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Fabrica, nobody can predict annual sales at this stage. I suggest you turn the question around and ask them what the smallest batch is that they will be interested in, and then we can see if we collect the interest. They are getting free advertising here (I could even make a banner for them if their quality is good) so they must judge the risk of a business decision from their side. They already have an idea how many people buy V-rollers (for CNC) from them, so they are actually in a better position to estimate the rail quantity. A big issue for them is whether they should simply copy the BWC/Hepco rails, or whether they go to market with an "angle iron" rail.
My gut feel is that the "angle iron" rail could get a nice market - it is a strong rail, gear racks are simple to fit, and the rail carries on a big face making shimming easy.
That link to lm76 looks typical of hundreds of linear rail suppliers. All those that I've tried have huge prices.... |
fabrica
Registered
Username: Daya
Post Number: 23
Registered: 10-2006
| | Posted on Wednesday, November 08, 2006 - 07:25 pm: |
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Yes Gerald, I accept your viewpoint on this issue. As you have said they are trying to pass the ball to us and trying to get us comitted on a sales figure. I will get in touch with them again and see what they could do offer to us. My thinking is that if we could get the rails at a competitive price we all could save time and concentrate on things which are more important matters than this. Specially on components and knowhow which cannot be bought off the shelf.
When we go through the download page in this website their are a lot more components to be completed. |
Greg Waggy
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Username: Gawnca
Post Number: 4
Registered: 11-2006
| | Posted on Wednesday, November 08, 2006 - 09:17 pm: |
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Gerald, In reply to your post numner 391, styrofoam would weigh a lot less than wood and therefore be a lot cheaper in shipping. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 436
Registered: 11-2005
| | Posted on Monday, November 13, 2006 - 06:55 pm: |
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By fabrica on Friday, November 10, 2006 - 05:40 am:
Below given is the latest reply I received from Yitong.
Regarding the rail, we are still in the calculation of the cost, our engineer suggest
that is possible you can still use the profile of the BWC design. If use your design,
we need to develop the model, and you should pay the mold cost which will increase
you cost.
What do you guys think.
By Gerald_D on Friday, November 10, 2006 - 07:04 am:
Fabrica, on the rails, I don't believe that Yitong is a willing partner that will undertake any expense for a new product line. They apparently are only willing to copy what other companies sell already. There is no way that I pay any company for mold/tool costs unless that mold/tool is under my control - in other words, checking that extra parts are not made from tools that I paid for.
Frankly and unfortunately, I believe the MechMate group is still too small to get into bulk buys and joint tooling costs. However, if suppliers want to take the initiative to help us, I will give them good advertising here. |
John_H
Registered
Username: John_h
Post Number: 11
Registered: 11-2006
| | Posted on Friday, November 10, 2006 - 08:15 am: |
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Naturally those guys aren't going to want to
tool-up for a few thousand feet of rail. They sell
container loads of bearings worldwide. This is the reason we who are trying to make these machines are going to have to get over our major reliances on "suppliers". What do we need. A straight bar of
steel 10 feet long. We are making machines that cut
to thousandths of an inch. Of course we can back up
and make a tool to make that rail. Grinders and spindles are pretty easy things to make. I have some other things I have to finish, but this "rail" problem is brewing in my mind.
John |
Gerald_D
Registered
Username: Gerald_d
Post Number: 422
Registered: 11-2005
| | Posted on Friday, November 10, 2006 - 08:54 am: |
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Regarding the source of rails, we musn't get hung up on finding absolute precision ground rail to build a CNC router capable of cutting kitchen counter tops and kiddie's jigsaw puzzles. My rails, produced with a common old milling machine, are doing a very nice job. Some guys even run V-rollers directly on the natural edge of angle iron and get a good result. So, let's not over-emphasise this ground-and-polished rail issue. Sure, if we can get such things at a good price, fine. But it is not absolutely essential.
As far as "straight" goes, that is an unreachable goal and we might as well discard it early. Rails are bent when you pick them up or screw them down. A rail that looks straight when lying on two trestles will be completely curved when you turn it over - gravity does that. The only requirements for rails are that they are free of of small lumps and bumps - the bigger lumps and bumps are cured (or caused) when the rails are screwed to its base. In this regard, a Hepco/BWC rail is no easier to install than a milled chunk of angle iron. (When I sight down that short piece of gauge plate mentioned for the z-rail, I can literally see how much I can bend it left/right just between my hands!)
Sure, it will be a pleasure to install a sturdy, straight, precision rail, but it is not an absolute requirement for producing a production CNC router that turns out furniture and décor all day long. |
John_H
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Username: John_h
Post Number: 12
Registered: 11-2006
| | Posted on Friday, November 10, 2006 - 09:09 am: |
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When I say straight, I don't necessarily mean
straight on an atomic level. Everything is flexible to some degree. I'm working with 3 ft sections (relatively short pieces) of 1.5 inch drill rod at the
moment and they are easily "flexed".
You're right. I or you or the next guy is not going
to make a "straight" rail if you want to look at it that way.
I wonder if a "straighten-able" rail could be produced. Maybe a "usable" rail?
John |
Gerald_D
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Username: Gerald_d
Post Number: 424
Registered: 11-2005
| | Posted on Friday, November 10, 2006 - 09:19 am: |
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John, I believe that if you came up with a "nice- looking" (?) angle iron rail, there would be a huge market of armchair shoppers wanting to buy it  . Notice that BWC/Hepco don't publish any specs on the "accuracy" of their rails and I suspect people buy it mostly because of its reputation and because you can buy it on-line. My rant above was another attempt to de-bunk the myth that rails must be bought instead of made. |
John_H
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Username: John_h
Post Number: 13
Registered: 11-2006
| | Posted on Friday, November 10, 2006 - 09:31 am: |
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I'm not really interested in selling anything.
But, I am absolutley convinced that this angle
on this piece of angle-iron is easily homemade.
The bearings like you made would be one of the last real barriers to the average guy. I believe they
were CNC turned and then hardened. I can make a few(enough) by hand but I still have to have them hardened. Haven't figured that out yet.
BTW, Have you thought about starting a post over
on cnczone.com? You deserve a lot more attention
than you're getting. There are lots of people with
experience on these big steel tables.
John |
fabrica
Registered
Username: Daya
Post Number: 31
Registered: 10-2006
| | Posted on Monday, November 13, 2006 - 03:26 pm: |
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How important is it to harden the V rail. In this country hardening facililties are hard to come by speically 11 foot lenths. Can somebody suggest to me a way out. I could buy BWC rail and fix it on to a machined L iron. I have spoken to several machine shops and their thinking is also on the same lines as mine. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 432
Registered: 11-2005
| | Posted on Monday, November 13, 2006 - 03:30 pm: |
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Who said you had to harden the V-rail? It is not specified on the drawings for the MechMate. |
fabrica
Registered
Username: Daya
Post Number: 32
Registered: 10-2006
| | Posted on Monday, November 13, 2006 - 03:34 pm: |
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Will their be no wear and tear on the rail and if it is not hardened how long will it last according to your experience. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 433
Registered: 11-2005
| | Posted on Monday, November 13, 2006 - 03:44 pm: |
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Our ShopBot that is now 6 years old has rails only 4.5mm thick/wide and the v-roller is size 2 (about 30mm diam.). In other words a smaller wheel on a narrower rail. We can see some wear on those rails, but it is not necessary to replace them yet.
The MechMate has 6mm wide rails with 40mm diam rollers. After 1 year I can see no wear at all - the marks left by the milling machine are still visible. My estimate on the life of this rail would have to be a lot higher than 6 years.
(Both machines have soft angle iron rails - there are about 3000(?) ShopBots with those thinner rails and I havn't heard of the rails being replaced due to wear and tear) |
fabrica
Registered
Username: Daya
Post Number: 33
Registered: 10-2006
| | Posted on Monday, November 13, 2006 - 04:08 pm: |
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Thanks for your info. You have given me enough confidence to have another round of discussions with the machine shop guys tomorrow.
Gerald one more question in our own workshop we do have a lathe machine and a shaper with 600 mm stroke is their any way that we could use the machines to do this job. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 434
Registered: 11-2005
| | Posted on Monday, November 13, 2006 - 06:32 pm: |
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For the V-topped rails, I am sorry, but those machines won't help you. The lathe will do all the jobs where the drawing number ends with a T (for turning). A 600mm stroke shaper is a beast of a machine! I'd like to see one in real life again - they are getting scarce in machine shops now that milling machines can do roughing cuts. Right now I cannot think where a shaper will help you with a MechMate. Sorry. |
John_H
Registered
Username: John_h
Post Number: 14
Registered: 11-2006
| | Posted on Monday, November 13, 2006 - 06:55 pm: |
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Hi Gerald,
How bad can it be to use some soft steel roller
on a soft steel rail. Wouldn't it work harden to
some degree? Many of us don't have access to machine shops and especially hardening facilities. If they had to be replaced every so often, that's not so bad is it?
Thanks
John |
fabrica
Registered
Username: Daya
Post Number: 34
Registered: 10-2006
| | Posted on Monday, November 13, 2006 - 07:06 pm: |
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If so will a surface grinder do the needfull. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 437
Registered: 11-2005
| | Posted on Monday, November 13, 2006 - 07:18 pm: |
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I think that soft wheels will give a couple of months of life, if not years. Guys like fabrica will not be wasting their time to make a first set of wheels from un-hardened steel. Any guy that knows his way with a standard (non-CNC) lathe should be able to use drawing M1 20 121 T to make passable wheels.
I am promoting hardened wheels because those are the ones I have experience with (and because there is this huge belief that there is only ONE wheel, the BWC/Hepco dualvee). I would love to see someone's experience with un-hardened wheels - these won't damage the rails, and hardened wheels can be fitted later.
Normal mild steels and angle irons don't really work harden. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 438
Registered: 11-2005
| | Posted on Monday, November 13, 2006 - 07:29 pm: |
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Fabrica, the biggest problem with cutting the rails to shape is to clamp the rails down straight. (The rails must be clamped about every 100mm to prevent vibration of the milling cutters.)
I don't know of 45 degrees stones used in a surface grinder, but that may be possible. Even in the grinder you will need to clamp the rails down straight.
With both methods, milling or grinding, you can only do maybe 600 to 800mm at a time. Then you must loosen all the clamps, move the rails, clamp everything straight again and do a new section. It is a tedious job, but it needs to be done.
There are some specialised smachines for doing long rails by they are very rare. A planer grinder, or a bedway grinder comes to mind - they are used to produce the beds of lathes. But please don't think you need the precision implied by grinding. A tolerance of 0.2mm om the milling is adequate. |
Greg Waggy
Registered
Username: Gawnca
Post Number: 22
Registered: 11-2006
| | Posted on Monday, November 13, 2006 - 07:32 pm: |
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Gerald,
This might be the best time to lay out your mounting holes and use them for your clamping points, ya think? Also, I think I saw where someone used some angle iron inverted so you can get a good 45 degree angle for grinding. It wouldn't take much then to mount the rail(s) and then grind them. |
John_H
Registered
Username: John_h
Post Number: 15
Registered: 11-2006
| | Posted on Monday, November 13, 2006 - 07:33 pm: |
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Thanks Gerald,
That one single answer now makes the machine a
real possibility for many more people.
Here's a link to a surface-hardening compound.
http://www.use-enco.com/CGI/INSRIT?PMAKA=505-0271&PMPXNO=945421&PARTPG=INLMK3
I haven't ever tried it but maybe someone who knows will give their opinion on such a thing.
Thanks
John |
Rails & Rollers