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  #1  
Old Mon 06 November 2006, 22:17
Gerald_D
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M110110M Angle iron rails for X and Y axes

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.
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  #2  
Old Wed 08 November 2006, 07:45
fabrica
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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.
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  #3  
Old Wed 08 November 2006, 08:25
fabrica
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Below given is a link to a interesting site of a manufacturer of linear motion products.

http://www.lm76.com
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  #4  
Old Wed 08 November 2006, 09:57
Gerald_D
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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....
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  #5  
Old Wed 08 November 2006, 10:25
fabrica
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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.
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  #6  
Old Wed 08 November 2006, 12:17
Greg Waggy
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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.
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  #7  
Old Thu 09 November 2006, 23:15
John_H
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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
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  #8  
Old Thu 09 November 2006, 23:54
Gerald_D
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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.
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  #9  
Old Fri 10 November 2006, 00:09
John_H
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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
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  #10  
Old Fri 10 November 2006, 00:19
Gerald_D
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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.
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  #11  
Old Fri 10 November 2006, 00:31
John_H
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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
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  #12  
Old Mon 13 November 2006, 06:26
fabrica
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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.
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  #13  
Old Mon 13 November 2006, 06:30
Gerald_D
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Who said you had to harden the V-rail? It is not specified on the drawings for the MechMate.
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  #14  
Old Mon 13 November 2006, 06:34
fabrica
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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.
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  #15  
Old Mon 13 November 2006, 06:44
Gerald_D
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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)
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  #16  
Old Mon 13 November 2006, 07:08
fabrica
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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.
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  #17  
Old Mon 13 November 2006, 09:32
Gerald_D
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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.
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  #18  
Old Mon 13 November 2006, 09:37
Gerald_D
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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.
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  #19  
Old Mon 13 November 2006, 09:55
Gerald_D
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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.
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  #20  
Old Mon 13 November 2006, 09:55
John_H
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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
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  #21  
Old Mon 13 November 2006, 10:06
fabrica
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If so will a surface grinder do the needfull.
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  #22  
Old Mon 13 November 2006, 10:18
Gerald_D
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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.
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  #23  
Old Mon 13 November 2006, 10:29
Gerald_D
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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.
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  #24  
Old Mon 13 November 2006, 10:32
Greg Waggy
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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.
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  #25  
Old Mon 13 November 2006, 10:33
John_H
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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?P...&PARTPG=INLMK3

I haven't ever tried it but maybe someone who knows will give their opinion on such a thing.

Thanks
John
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  #26  
Old Mon 13 November 2006, 10:35
Greg Waggy
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M110110M Angle iron rails for X and Y axes

John,

I wonder how that works? I was thinking along the lines or oil drenching for hardening.
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  #27  
Old Mon 13 November 2006, 10:39
John_H
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Hi Greg,

Click on the enco page where it says "Master Catalog Page 648", they say how it works.

John
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  #28  
Old Mon 13 November 2006, 10:46
Gerald_D
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Kasenit is good for case-hardening small parts such as the pinion gears. Parts need to be red hot before being dunked into the Kasenit. You are going to need a long oven and a lot of Kasenit before you can dunk a rail.... Plus, you have the usual heat-distortion problems.
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  #29  
Old Mon 13 November 2006, 10:46
Greg Waggy
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Thanks John, I just looked it up in my catalog. I guess its just a dip process and for small parts it looks like it would work. I wonder if you leave the part longer if the hardness gets deeper. $9.71 (on sale)a quart isn't too bad. I have dealt with Enco and they are good.
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  #30  
Old Mon 13 November 2006, 10:49
Greg Waggy
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Well, here's the scoop I just got on Kasenit.

Notes:

Produces a wear surface (surface hardening) on low carbon steel, low alloy steel, iron.

Non-poisonous, non-explosive.

Application instructions (from Kasenit) for Low Alloy or Low Carbon Steel:
There are two methods of application.
Method A: Heat the work uniformly to a bright red (1650 - 1700 degrees F), remove any scale with a wire brush, dip, roll or sprinkle the Kasenit powder on the component. The powder will melt and adhere to the surface, forming a shell around the work. Reheat to 1650 - 1700 degrees F, hold at this temperature for a few minutes and quench in to clean cold water. This will give the component a completely hard case of uniform character and depth.

Method B: If a deeper case is required, then a container for the compound can be used. A discarded can, lid or tray is suitable for this purpose, but care must be taken to burn off the tin coating before use. Completely cover the component with compound and heat to a bright red (1650 degrees F) for five to thirty minutes, depending upon the depth of case required. Quench only the component in clean, cold water unsing dry tongs for handling.

Rates of Penetration: After heating the component to 1650 F using method B,

Case depth .005, Time 15 minutes

Case depth .010, Time 30 minutes

Case depth .015, Time 40 minutes

Case depth .020, Time 50-55 minutes

Method for Cast or Tool Steel:
Heat the article to a light yellow. Deposit it in powder and leave it there until its right tempering heat is reached (see list below). Then plunge the metal into clean, cold water. This will bring out the hardness and also prevent cracking.

Heat Tempering List:

Small cutting or turning tools, cutting edges of knives, planing tools and reamers, small case hardened parts:
Light straw color, 440 F

Carbon steel milling cutters, large cutting or turning tools, slotting tools and small punches or dies:
Straw color, 460 F

Drills, small taps, profile cutters, screwing dies and hammers:
Dark straw, 480 F

Press dies, shears, wood cutting tools:
Orange, 500 F

Chisels, large punches, pressing dies and cutlery:
Light purple, 525 F

Saws, drifts, large dies and heavy chisels:
Purple, 540 F

Springs or portions of tools to be locally tempered to give maximum resilience:
Blue, 560 F
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