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  #151  
Old Mon 02 June 2008, 17:36
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Ed,

Thanks for the help on the router / Mach problem. I had everything wrong. It works great now.

Figured out the homing/limit issues yesterday.

Again, Thanks.
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  #152  
Old Mon 02 June 2008, 18:00
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
Sorry I didn't get on the computer Sun., sounds like you got it going!
I will be waiting patiently for some pictures with sawdust
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  #153  
Old Tue 03 June 2008, 17:22
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
small job

did a faceplate for an 18watt amplifier that I build. I turned out beutiful. I am starting to see what the MM can do. I finger jointed the wood for the amp cabinet also yesterday and got it glued up today. when I get it all together I will post a photo of what the amp looks like.
Attached Images
File Type: jpg photo faceplate.jpg (104.6 KB, 1000 views)
File Type: jpg DSC00092.JPG (75.7 KB, 997 views)
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  #154  
Old Tue 03 June 2008, 20:51
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
ED,
Did you finger joint the cabinet on the MM also? If you go to the talk shopbot forum, and search for finger joint and knapp joint you will find some pics of guys doing this on their cnc. The front panel looks great. how did you get the yellow, was it painted or two layer plastic?
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  #155  
Old Tue 03 June 2008, 21:12
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Ed,

I like it. Very nice.

Hey, while waiting on the VCarve Pro, I've been playing around with motor speeds, etc. You may want to consider changing pinions to the 35 tooth for the X axis. I'm not cutting, so these are not valid tests, but, my gut tells me that this MM is well designed.
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  #156  
Old Wed 04 June 2008, 00:12
dmoore
Just call me:
 
Quote:
Originally Posted by Greg J View Post
You may want to consider changing pinions to the 35 tooth for the X axis. I'm not cutting, so these are not valid tests, but, my gut tells me that this MM is well designed.
Greg -

I'm guessing you moved from 30 to 35 tooth with the 7.2:1? Whats the thinking on moving to the 35's over the 30's?

Thanks,
david
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  #157  
Old Wed 04 June 2008, 06:23
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
David,

This is my first experience with any kind of CNC. So I'm learning as I go.

When I started this build, Doc Tanner was using this combination, and having good results. That's the main reason.

Also, the pinions are relative low cost and easy to change out. If I didn't/don't like the results, I can always change to another pinion.
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  #158  
Old Wed 04 June 2008, 07:58
dmoore
Just call me:
 
Quote:
Originally Posted by Greg J View Post
Also, the pinions are relative low cost and easy to change out. If I didn't/don't like the results, I can always change to another pinion.
Well I will say that you only drop .0001" of resolution from going from 30's to 35's. You also drop your stepping speed from 25.5 KHz to 21.8 KHz - imporant for those with slow computers. Also your motor speed drops over 250 RPM, thus giving your more torque (if you need it).

Here is a good thread on this topic:

http://www.mechmate.com/forums/showthread.php?t=768
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  #159  
Old Wed 04 June 2008, 08:49
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
The finger joints yes it was easy to do on the MM, I just sandwiched the two pieces between two spoilboards vetically to the end channel of the MM and set up a simple profile path in vcarve, then did the opposite tool pathe for the top and bottom pieces. I used a 1/2" bit and cutt slightly deeper than the thickness of the boards. The plastic is from www.Johnsonplastics.biz They have an endless variety of colors. The surface is a different color than the inner, that gives you contrast on the lettering. The also have reverse engraving plastics where you engrave the letters bacwards on the back of the plastic then fill the void or paint the void a different color for the contrast. Basically the same way they do amplifier faceplates.


If the resolution is good and every thing else is working good is there a reason besides the travel or cutt speed to change the pinion size?

Actually it seems to move plenty fast for me with the 20tpi pinion, I have been slowing down the letter engraving to about 60ipm. The bit was hot enough you couldn't hold it in your hand after cutting the plastic at that speed.
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  #160  
Old Wed 04 June 2008, 08:50
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
Here is a source for engraving bits for wood and plastic, they have pretty much anything you may need.

http://store.multicam.com/osc/index....qp3tjuu79cn6g1
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  #161  
Old Wed 04 June 2008, 09:27
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by ekdenton View Post
If the resolution is good and every thing else is working good is there a reason besides the travel or cut speed to change the pinion size?
Pinion size affects:
Speeds - big=fast..........small=slow
Force/torque - big=low force/torque.........small = high force/torque
Resolution/chatter marks - big = poor resolution with marks.....small=fine resolution/less marks
Wear/life of pinion - big=longer life.......small = shorter life
PC's frequency output - small=high freq/fast PC.......big=slower PC

It is all a compromise between these factors.
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  #162  
Old Wed 04 June 2008, 11:47
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Quote:
Originally Posted by ekdenton View Post
I ordered enough rail to do my y rails and my z slide. .
Ed,
Did you use the aluminum channel for the Y with the hardened rails? From the pictures I see, it looks as though your rail holder is painted (steel?) Was there any problem with the Z and the slight offset with the hardened rails mounted that way? ( Normally, the V would be at the end of the plate, not offsett) If you have more pictures of the Y rail setup I would like to see them.

thanks

Heath.

Last edited by domino11; Wed 04 June 2008 at 11:50..
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  #163  
Old Wed 04 June 2008, 13:49
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
Hi Heath,
I was going to grind my own rails and I got bad cutts on the y rails so I took the crooked cutt pieces to a friend that has a mill and had them milled down to 7/8". If I ever do another MechMate though I really feel it is better for me to go with the aluminum and premade hardened rails. If you look at the total cost of the MM (around 5-6K), and then look at the cost of grinding your own rails and include the cost of the brackets to hold the grinder and blades and grinding wheels and a grinder if you don't have a fairly heavy duty one already. Then compare that to the aluminum angle and premade rails and at most it's probably $150-$200 difference. It's my opinion that is is worth $200+ no to have the stress and time spent grinding and cutting wondering if it will work ect ect ect. So $200 on a 5-6K machine is pretty insignificant.

The offset didn't matter it just took less shim washers than it would take for a DYI ground rail. After installation they are about 3/16 narrower.
Here is a photo of how they bolt to the z slide plate.
If you use steel angle rather than the aluminum like I did you will have to also have the rail milled off for the radius of the steel angle, if you use the aluminum you don't have to do that it doesn't have a radius it is square on the inside corner.
Attached Images
File Type: jpg DSC00052.JPG (70.1 KB, 1034 views)
File Type: jpg untitled (2).jpg (53.0 KB, 1009 views)

Last edited by ekdenton; Wed 04 June 2008 at 14:03.. Reason: added photo
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  #164  
Old Wed 04 June 2008, 21:23
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Ed,
Thanks for the extra pics and explanation. I am still on the fence for the grinding or buying the pre made rails. I really like your Z slide idea, looks great. It looks like you did the 14 inch version of the slide? Did you use higher table sides to get more Z travel? Was just wondering how that worked out for you if you increased the Z clearance.
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  #165  
Old Wed 04 June 2008, 21:47
RLH3
Just call me: Roman
 
Reno, NV
United States of America
Quote:
Originally Posted by Gerald D View Post

(snip)

Wear/life of pinion - big=longer life.......small = shorter life

(more snippage)

It is all a compromise between these factors.
You speak of pinion life here, Gerald. Your machines have been running longer than anyone else's and from you descriptions, pretty much 40+ hours a week. Have you experienced an appreciable level of wear? Do we have a clue what the MTBF is on the pinions or the racks? I would think that the motors would wear out first.

This just kind of caught my attention, and is not really something that concerns me too much.

Roman

Last edited by RLH3; Wed 04 June 2008 at 21:50.. Reason: because I cannot spell!
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  #166  
Old Thu 05 June 2008, 00:26
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Can't see/feel any significant wear on our MechMate's pinions and racks (without stripping it down to inspect). Our ShopBot had narrow unhardened pinions which wore out after maybe 1000 hours of running. The MechMate must be over 3000 hours by now. The logic of longer life for bigger pinions is simply based on the fact that more teeth will be sharing the work.
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  #167  
Old Thu 05 June 2008, 08:56
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
I did the 14" slide but I am using the 6" channel rails. Since there is really no difference in cost in doing the longer slide, I did that just in case I may need to raise the rails someday. I probably should have used the 7" or 8" channel but then hind sight is 20/20.
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  #168  
Old Thu 05 June 2008, 09:51
dmoore
Just call me:
 
Quote:
Originally Posted by ekdenton View Post
I did the 14" slide but I am using the 6" channel rails. Since there is really no difference in cost in doing the longer slide, I did that just in case I may need to raise the rails someday. I probably should have used the 7" or 8" channel but then hind sight is 20/20.
I'd agree with you - I wish I had gone to 8" channel instead of the 7" I built with. It would have solved the problem with the X cable chain brackets being to short and it would have given me full use of the 250mm Z slide (with the support/spoil boards in place). I would also guess that it would be stiffer with the larger web of the 8" channel.
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  #169  
Old Sat 07 June 2008, 09:43
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
I am working on my dust collection now and I have a question. I see alot of you guys are building a sliding foot that attatches to the router mount. My router mount has only one hole for foot, that doesn't seem like it would work.

Do you have to have the sliding foot for the dust collector to work?

I was wondering if I built an adjustable pipe with an open bottom tapered intake that will be ajustable so that I can set it just above the work piece and it will sit about 4-5inches behind the router. I drew up a little picture of what I had in mind showing about where the router will be, but I don't know enough about what I need and what works yet. The dust cyclone I have is about 1100cfm, its pretty strong, I accidentally sucked the remote control for the dust collector off the table that was a few inches from the collector tube when I turned it on. That is why I was wondering if I actually needed a foot that totally encapsulated the router bit with the plastic or broom attatched to the foot.
Attached Images
File Type: jpg dust intake.JPG (21.3 KB, 944 views)
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  #170  
Old Sat 07 June 2008, 10:14
dmoore
Just call me:
 
ED -

Have you seen this post that I made about the fully adjustable dust foot that encloses the bit but can be opened up to allow a view of the material for setting Z and changing bits? My design is independent of the router mount, mounting to the existing mounting holes in the y-car. I has the ability to either ride a fixed level above the work surface or it can be fixed to the Z slide and thus go up and down with your bit. I have a 600 CFM system and pretty much nothing gets out. By the end of this coming week, I hope to have the design fully tested and I'll post the files for others to cut.

David

Last edited by dmoore; Sat 07 June 2008 at 10:18..
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  #171  
Old Sat 07 June 2008, 10:23
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by ekdenton View Post
Do you have to have the sliding foot for the dust collector to work?
My view is that the foot should be fixed to the y-car, and that it should not ride up and down with the z-axis. (Realise that I am biased to production board cutting). The optimum height of the skirt relative to the top surface of the board is in a fairly narrow range - if a thick board needs to be cut in 4 passes, inceasingly deeper, then the foot needs to stay at a steady height and not be squashed right down at the end.

We do often cut with the front of the dust foot removed and there is only a small loss in performance. Whether that leaves enough dust in the air to kill you......well, I don't know......yet! (Suspect though that the open foot still gets the "fines" while the coarser chips fling out)
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  #172  
Old Sat 07 June 2008, 11:31
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
Thanks guys that makes sense to me, and seems like it would be easier to build by attatching to the z car rather than the slide. I don't mind sweeping some of the larger stuff as long as it gets most of the fine powdery dust.

David, I will check out the thread, thanks.
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  #173  
Old Fri 13 June 2008, 14:05
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
finished cab fingerjointed with MM

The finger joints that I had cut in the earlier photo turned out way better than I could have imagined them to. It was also probably faster than using my dovetail jig also. I like the fit and the corners better than what I was getting with the dovetail jig. Just need more cabinet clamps though before I do any more, the glue was almost set before I finished clamping this one, because I was short on clamps.

This is a birch cab for a Marshall tube amp.

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  #174  
Old Fri 13 June 2008, 14:16
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Very nice Ed, I like it.
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  #175  
Old Fri 13 June 2008, 15:06
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Ed,

Very nice finger joint. I hope that when my MM is built, I get the same quality of work.
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  #176  
Old Fri 13 June 2008, 20:45
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Umm Ed, I thought that you were a steelworker? Blokes like us are not supposed to do nice woodwork...or so I tell myself when I gouge some wood by mistake.

Good Stuff!
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  #177  
Old Thu 19 June 2008, 15:49
ekdenton
Just call me: Ed #8
 
Alamogordo, NM
United States of America
I noticed that all the wiring for the relays has been removed from the thread it was on guess things were cluttered and got cleaned up a little, I couldn't find anything in the archives either so I guess maybe it got deleted. For those interested in putting the j-box with the relays and bringing 12v to the gantry, I tried to clean up the drawing a little. I mounted the box on the opposite side from the 0,0 side of the table since I did not use three of the pushbutton stations, there was plenty of room there. There is plenty of room for a small 1-1/2" x 2" board, relays (common avaliable at Ratshack or Mouser or any place that sells electronic parts) terminal strips and lots of room for making the 7core wire connections. I added a small outlet on the top of the box for a 12vdc source on the gantry in case I need it later.
Attached Images
File Type: jpg proxi wiring diagram (2).jpg (57.7 KB, 826 views)
File Type: jpg DSC00062.JPG (78.3 KB, 833 views)
File Type: jpg PROXY RELAY BOX.jpg (63.9 KB, 826 views)
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  #178  
Old Thu 19 June 2008, 19:17
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Ed,
Fantastic small package of limit switch/proximity relays. A little soldering and breadboard fun I see! Great, clean, compact solution.
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  #179  
Old Thu 19 June 2008, 22:52
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Hi Ed,

I did not delete anything like that......are you talking of the posts in this thread. #'s 114 and 119?

Some very neat wiring! I can almost forgive the colour....
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  #180  
Old Thu 19 June 2008, 23:09
hennie
Just call me: Hennie #23
 
Roodepoort JHB
South Africa
Hi Ed

Nice toy bet you have a lot of spare time to do good job.
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