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Gerald_D
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Username: Gerald_d
Post Number: 365
Registered: 11-2005
| | Posted on Friday, November 03, 2006 - 10:09 am: | 
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After finding that linear bearings are exhorbitantly expensive, plan B.....
"Gauge Plate" is very precise, high-quality, slightly hard tool steel that can be hardened even further. Running pre-loaded big V-rollers on this stuff should work okay.
Typical standard sizes./. More
Thinking of a 6mm x 100mm plate, ground as per the pics in this thread and screwing a backing/stiffener to it. |
Gerald_D
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Username: Gerald_d
Post Number: 368
Registered: 11-2005
| | Posted on Friday, November 03, 2006 - 02:00 pm: |
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Yellow is the hard plate with a green 50x25x3mm [2x1x.125"] tube screwed to it. Rollers BWC size 3. For this route, I'd ask to spindle maker to put more tapped holes in the top end of the spindle - that would add a lot of stiffness to the assembly. (I will drill and tap the spindles here already). |
Brian Backner
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Username: Allegheny
Post Number: 3
Registered: 07-2006
| | Posted on Friday, November 03, 2006 - 03:48 pm: |
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For those stateside, you might consider Starrett precision ground oil hardening flat stock (tool steel). It would need to be ground to shape, i.e., it can't be milled, but it has the advantage of tremendous strength, very precise tolerances (typically 0.0001"/ft) and is widely available.
A good outlet is WT Tool (www.wttool.com):
1/4" x 4" x 18" is $42
http://www.wttool.com/product-exec/product_id/10206
1/4" x 4" x 36" is $85
http://www.wttool.com/product-exec/product_id/10394
They have many additional cross sections available.
Brian
Walpole, MA |
Gerald_D
Registered
Username: Gerald_d
Post Number: 369
Registered: 11-2005
| | Posted on Friday, November 03, 2006 - 04:40 pm: |
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Hi Brian, I think that is the same stuff that I am talking about, but we don't have big problems milling/drilling/tapping it?? Sure, at 230 Brinell it is harder/tougher than "mild steel" which is around 120. (If memory serves me right).
Your prices match those over here. |
Sheldon Dingwall
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Username: Sheldon_dingwall
Post Number: 12
Registered: 08-2006
| | Posted on Friday, November 03, 2006 - 08:22 pm: |
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By the time you pay for the material and modifications, would it not be easier/cheaper to just buy BWC rail? |
Brian Backner
Registered
Username: Allegheny
Post Number: 4
Registered: 07-2006
| | Posted on Friday, November 03, 2006 - 10:49 pm: |
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Gerald,
You are right about the oil hardening stock being machinable; in my post above, I was thinking of the high carbon air hardening steels - while they're still machinable, barely, they are much more unforgiving of tooling. I've typically had this stuff precision ground. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 371
Registered: 11-2005
| | Posted on Saturday, November 04, 2006 - 08:17 am: |
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Sheldon, that is a typical view of the BWC rails, but it is not that easy....
BWC rails have a nice edge, but they are actually very flexible and flimsy. (a size 2 track is only 16x6mm [5/8x1/4"] overall) You still have to drill a lot of holes in them to screw them to a firm base. And then they end up being only as straight as the base that they are screwed to.
My logic is to put the V-edge directly onto the "firm base" if we have to go to trouble of making the base fairly precise. It saves a lot of drilled holes. (My Hepco literature avoids recommending screw sizes/spacings).
It is not that difficult to put a passable V-edge onto a short flat bar for the z-slide. We might not end up with something as "precise"(?) as BWC but it is going to be simpler, cheaper and still do a great job. And, if we work around a "flat bar" design, people can still easily add BWC rails to it. The basic "gauge plate" tool steel used all over the world is the perfect stuff for screwing BWC/Hepco rails to. |
Sheldon Dingwall
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Username: Sheldon_dingwall
Post Number: 13
Registered: 08-2006
| | Posted on Saturday, November 04, 2006 - 11:45 pm: |
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I was thinking of their double edge flat slide. It's available up to 76 mm wide. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 375
Registered: 11-2005
| | Posted on Sunday, November 05, 2006 - 08:40 am: |
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How thick is it? The 76 direction is probably adequate, but I guess it is going to need something more to stop it from bending in the x-direction, or from twisting when you take a heavy y-cut. Price? |
ralph hampton
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Username: Rhfurniture
Post Number: 27
Registered: 08-2006
| | Posted on Sunday, November 05, 2006 - 07:28 pm: |
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Sounds like Hepco GV3:
http://www.hepcomotion.com/db_pages/products/proddetail.php?id=0001&cat=comp
They are the UK link to bwc.
R/ |
Sheldon Dingwall
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Username: Sheldon_dingwall
Post Number: 14
Registered: 08-2006
| | Posted on Monday, November 06, 2006 - 12:05 am: |
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I was thinking flat re-inforced by your tube idea. They spacer slide is thicker - 19 mm I believe. But probably not thick enough.
 |
Gerald_D
Registered
Username: Gerald_d
Post Number: 381
Registered: 11-2005
| | Posted on Monday, November 06, 2006 - 06:53 am: |
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If you reinforce the thin plate with a backing tube that should work fine. Just remember that the plate should be soft enough so that you can drill it.
A side note: Hardening of steel does not make it any "stiffer". For this slide application, the hardening is solely to improve wear resistance. |
Gerald_D
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Username: Gerald_d
Post Number: 392
Registered: 11-2005
| | Posted on Tuesday, November 07, 2006 - 05:45 pm: |
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Here is some progress this afternoon:
The grinding in the table saw was surprisingly easy (20 minutes) A 175mm wheel protruding 26mm above the table surface gave the 2x45 degrees, albeit very slightly concave. Then some draw filing with a fine file and a bit of emery stone (20 minutes). There is scope for refining this process, but already the results are an A-class "pass".
If I had to do a lot of these, I would use a thicker(wider face) stone of a finer grit, but the 3mm thin cutting disc (coarse) was not too bad. The biggest job was to make a centralising bush for the disc in the table-saw.
Can I suggest you guys try it with any old piece of flat bar before you believe me?  |
Gerald_D
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Username: Gerald_d
Post Number: 395
Registered: 11-2005
| | Posted on Tuesday, November 07, 2006 - 10:11 pm: |
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I drilled some holes in that plate tonight. It sure is much harder than mild steel, but not impossible to work with. (Some stainless steels are much worse)
(The stockist of those $1200 linear IKO bearings came to me with a $500 price today. I think he is trying to move dead stock.)
the grinding discussion moved here |
Gerald_D
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Username: Gerald_d
Post Number: 402
Registered: 11-2005
| | Posted on Wednesday, November 08, 2006 - 06:04 pm: |
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A rough assembly.......
(the big hole in the tube is referred to in this thread for this quick change system)
Those 4 screwheads seen above are of screws going all the way through into the spindle's alu body. (2 long (shiny heads) and 2 short (black heads))
The countersunk screws above are tapped into the 3mm [1/8"] wall of the rectangular tube. Some extra holes in case positions need to be adjusted (and to see how long the tooling lasted while cutting the gauge plate - no problems)
The cut-away of the rect. tube is for the dust hose. The screws into the spindle body are near the collet end. I am tempted to drill+tap the spindle body near the top end for more screws - the spindle body is a nice flat, strong extrusion.
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Gerald_D
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Username: Gerald_d
Post Number: 457
Registered: 11-2005
| | Posted on Wednesday, November 15, 2006 - 08:32 pm: |
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The eccentric bushings and rollers for the z-slide:
The eccentric bushes are modified bolts (drawing will be provided). Unlike BWC/Hepco, these bushings and support collars are relieved to avoid contact with the seals.
 |
Gerald_D
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Username: Gerald_d
Post Number: 467
Registered: 11-2005
| | Posted on Friday, November 17, 2006 - 05:13 pm: |
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Some progress:
 |
Evan Curtis
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Username: Evan
Post Number: 18
Registered: 12-2005
| | Posted on Friday, November 17, 2006 - 07:20 pm: |
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paraphrasing Tony the Tiger "It look's GGGRRREAT! |
Gerald_D
Registered
Username: Gerald_d
Post Number: 474
Registered: 11-2005
| | Posted on Friday, November 17, 2006 - 08:50 pm: |
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Thanks Evan, that encouragement earns you one more pic:
 |
Gerald_D
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Username: Gerald_d
Post Number: 485
Registered: 11-2005
| | Posted on Sunday, November 19, 2006 - 01:35 pm: |
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The weekend's work - first prototype fully assembled (almost):
 |
Robert Cheal
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Username: Robert_cheal
Post Number: 15
Registered: 08-2006
| | Posted on Monday, November 20, 2006 - 02:52 am: |
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It looks awesome and very well thought out.
Just curious what is the expected life on the "Gaslift". And also is it difficult to get the correct tolerances on the mounting holes after the bracket has been bent into shape. I guess a good shop could bend it right the first time. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 488
Registered: 11-2005
| | Posted on Monday, November 20, 2006 - 06:59 am: |
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Hi Robert. The matching holes in the Y-car are oversize and slotted. (You also need the slotting for adjusting the Z perpendicular to the table.) This "tower" will not work in a ShopBot y-car because that car can't support the 4 legs of the "spider" firmly. With the stiff car of the MechMate, the four attachment points of the spider are slightly flexible so that they can conform to the car. The stiffness of the y-car is used directly behind the V-rollers.
I don't know the life expectancy of a gas-lift in this application. We have nearly run one year with the first one and so far, so good. However, I will design a conventional spring system as well - anybody have a skyhook to hold the top end of a spring?
(apologies for the home welding quality on those nuts) |
Alan Conolly
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Username: Alan_c
Post Number: 3
Registered: 07-2006
| | Posted on Monday, November 20, 2006 - 08:42 am: |
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Hi Gerald
Very neat design - n boer maak n plan!
How do you maintain pressure on the pinion gear to hold it into the rack, or will that become apparent once it is mounted into the Y car? |
Gerald_D
Registered
Username: Gerald_d
Post Number: 489
Registered: 11-2005
| | Posted on Monday, November 20, 2006 - 08:58 am: |
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Hi Alan. You can see a capscrew sitting next to the motor on the motor-mounting plate. A spring is hooked around it and the other end of the spring goes down to the Y-car. Same as the situation with the current linear bearing version:
 |
Dirk Hazeleger
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Username: Dirk
Post Number: 48
Registered: 12-2005
| | Posted on Monday, November 20, 2006 - 04:16 pm: |
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Hey Gerald
I noticed the motor on the new Z your using direct drive. Is that what your planning on? What are your thoughts as to direct drive vs geared motors for all axis.
Dirk |
Gerald_D
Registered
Username: Gerald_d
Post Number: 490
Registered: 11-2005
| | Posted on Monday, November 20, 2006 - 04:46 pm: |
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Hi Dirk, my suggestions on motor selection are in this thread. However, that thread actually applies more to the x and y axes than the z. We must recognise that the demands on the z-axis are a bit different....
The z-axis accels/decels. a lower mass, but that mass could be unbalanced. The cutting forces should be lower. General impression is that the z-axis is less demanding on a motor than the other two main axes. Even debatable whether a micro-step driver is needed for the z-axis.
Having said that, our one table runs a direct drive motor and the other runs a geared motor. I really can't say that one is better than the other. But, for a heavy router/spindle the geared version should be better. The gearing gives a bigger "detent" when the motor is switched off, and the router/spindle mass doesn't need to be compensated that accurately.
I plan to run this axis with an ungeared motor as an experiment with the heavy spindle, but I could run into problems with the gas-lift's weight compensation. I have to design a coil spring alternative in any case, because everybody won't be able to locate gas-lifts as easily.
That motor mount plate can take either geared or ungeared motors - the pinion location will stay the same. |
Paul A
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Username: Paul_a
Post Number: 5
Registered: 12-2005
| | Posted on Monday, November 20, 2006 - 07:19 pm: |
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Hi All
If you were not happy about beveling your Guage Plate you could aways form the Z slide with a few pieces of sheet steel and a couple of BWC rails bolted between.
Just a thought
 |
Gerald_D
Registered
Username: Gerald_d
Post Number: 491
Registered: 11-2005
| | Posted on Monday, November 20, 2006 - 07:35 pm: |
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If you want to go that route, it would be better to reverse the BWC rails so that their shoulders butt against the stiffer plate, the flat one. I would just put the rails on the edges of a thinner gauge plate, and still go for the box-section backing. |
fabrica
Registered
Username: Daya
Post Number: 122
Registered: 10-2006
| | Posted on Wednesday, December 13, 2006 - 10:29 am: |
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In drawing number 10 40 330 (SA). You have given two sets of dimensions. One set for the Inch option and the other for the metric option. What does it mean? |
Gerald_D
Registered
Username: Gerald_d
Post Number: 633
Registered: 11-2005
| | Posted on Wednesday, December 13, 2006 - 10:48 am: |
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The inch guys sell that plate as 4"x0.25"x18" and the metric guys sell it as 100mm x 6mm x 500mm. Both those sizes will work without sawing the plate any shorter. |
Charlie T
Registered
Username: Popbing
Post Number: 7
Registered: 11-2006
| | Posted on Wednesday, January 03, 2007 - 08:51 pm: |
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I think I'd rather have a router for the cost of them. But Im wondering about mounting it and the clearance on z slide. Spindles ?? hmmmm. BTW why do you have a metric and imperial option on the dimentions of the gauge plate, metric is way larger than the imperial one. Options are great but the plan becomes distorted and hard to follow. |
Charlie T
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Username: Popbing
Post Number: 8
Registered: 11-2006
| | Posted on Wednesday, January 03, 2007 - 09:00 pm: |
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Nevermind ... what is the matter with me? The last posts talk of this very thing. You say either "Will" work but,, how does this effect drawing 10 40 360 and 10 40 330. This is what becomes hard to follow. Those drawings have no option but if cut will not work if you went with the 18" imperial option. Help me understand what Im missing. Its just hard to know what it will effect not being the one who drafted them. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 680
Registered: 11-2005
| | Posted on Wednesday, January 03, 2007 - 09:02 pm: |
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Charlie, what length plate is readily available to you? |
Charlie T
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Username: Popbing
Post Number: 9
Registered: 11-2006
| | Posted on Wednesday, January 03, 2007 - 09:05 pm: |
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The place Im getting my gauge plate says it can be larger than 18"x4" also he tells me its A2 tool steel. Is that the right stuff ??? See now Im all worried that Im headed down the wrong path. I wanted to buy it today and get it to the fab guys. |
Charlie T
Registered
Username: Popbing
Post Number: 10
Registered: 11-2006
| | Posted on Wednesday, January 03, 2007 - 09:08 pm: |
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I wish we had an all metric plan and a all imperial plan. This guy told me that he cant work in the tenths of an inch or metric. Thats going to be a real bummer. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 681
Registered: 11-2005
| | Posted on Wednesday, January 03, 2007 - 09:25 pm: |
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Drawing 10 40 330 shows an arrow where the 18" plate will end. I could have told all the metric guys to cut their plates shorter to 18" just to have a standard set of drawings, but why should I waste their time? (or do a second set of drawings in units that are foreign to me?) |
Charlie T
Registered
Username: Popbing
Post Number: 11
Registered: 11-2006
| | Posted on Wednesday, January 03, 2007 - 09:32 pm: |
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Yea I know what you mean its kinda up to us USAers ( I hate inches metric is so much better)
Laser cutter guy said no problem he can work in tenths of an inch but some are just dumbfounded by the thought of this. |
Travis H
Registered
Username: Flyin04
Post Number: 5
Registered: 11-2006
| | Posted on Wednesday, January 03, 2007 - 09:38 pm: |
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I don't find it a problem working in either or. Just use the magic number 25.4 to convert the numbers.
Gerald, keep up the good work Mate. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 682
Registered: 11-2005
| | Posted on Wednesday, January 03, 2007 - 09:46 pm: |
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Charlie, in this thread I got the impression that the inch folk are okay with decimal inches. Maybe you should look for another fabricator?
Thanks Travis. |
Charlie T
Registered
Username: Popbing
Post Number: 12
Registered: 11-2006
| | Posted on Wednesday, January 03, 2007 - 10:35 pm: |
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Im thinking thats it , come to find out the linked "precision ground" ones are way nicer than what I could get from him. But I guess it could work if It had one nice factory edge, the quote was 64$. Ill just wait on this peice for now. |
fabrica
Registered
Username: Daya
Post Number: 178
Registered: 10-2006
| | Posted on Monday, January 15, 2007 - 06:23 pm: |
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Gerald, Have you given the width of the slide plate after machining the V rails. What I find is only the sawing dimensions given. Please educate me on this.
The sawn width of the plate was 100 mm. The drawing was given to my machinist and since he could not find the final dimensions (width) of the plate after machining, he had finished the plate to a 94 mm width. When we tried to put the rollers in today we found that even after making adjustments to the extreme with the ecentric busings the rollers would not fit into the plate.
The overcome this situ the easiest way out was to make new holes in the spider plate. We plugged the exisiting holes by screwing in bolts onto the existging holes and the grinded them flat. Then we increased the width between holes by 2 mm on all two sides. We were able to overcome the problem by doing this.
After doing this alteration we are in a situ where the motor mounting screws are hitting the spider bracket while moving. To overcome this we are planning to contersink the bolt which is clashing with the spider plate.
The ideal final width (after maching the V rails)of the plate should be around 90 mm. The ecentric busings will take in widths between 88mm and 93 mm according to our calculations. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 714
Registered: 11-2005
| | Posted on Monday, January 15, 2007 - 07:06 pm: |
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Gauge plate is very exactly 100mm wide, and there is no need to machine it any narrower. Therefore, the finished size is 100mm (as originally supplied).
Then, for drilling the holes in the spider plate, according to drawing 1040430D, the dimension is given as (132) in brackets with a note "To suit slide and V-rollers". Maybe I should have made it clearer that dimensions in brackets are only a guide and must be checked against other parameters. In this case, the choice of V-roller will make a difference, and whether the gauge plate is 100mm or 4 inches.
The eccentric bushings are also used to get the z-axis perpendicular to the table.
I am concerned about collisions between your router (and bracket) with the z-axis rollers....? |
fabrica
Registered
Username: Daya
Post Number: 181
Registered: 10-2006
| | Posted on Monday, January 15, 2007 - 07:24 pm: |
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I am using the rollers from supremebearings. Maybe their are dimensional differences between BWC and Supreme rollers.
The collision between router and rollers cannot be that difficult to overcome. The bolt head just has to be taken care of. Since we have come this far this minor thing cannot be a big issue. |
40. Z-Slide