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  #121  
Old Sun 29 December 2013, 20:08
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
X-Rails Attached

X-Rails are attached. Despite trying to do very careful layout on the beams, I am still seeing a +-1/16 inch variation on the spacing. Most of that contributed by the bowing of the rails, but some also from just having to use a hand drill which managed to wander some.

Have to go back to the real world tomorrow, but I have Jan 1 off. So I will mill some elongation to the holes to get some adjustability. If I can not get the bow out with bolt pressure, I think spot heating in a few spots will fix it. I have not done heat straightening before, so I will save that option for a last resort.

I am looking at the gantry more closely as I get to the point of assembling it. I am thinking I will start with welding up the Z-car first. That way I can attach the roller bearings to get an exact measurement of the distance between them. For that I can calculate where to drill the holes in the cross tubes, Y-rails and nut plates. I have a mill with a DRO. So getting with a thousandth of an inch is pretty easy.
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  #122  
Old Sun 29 December 2013, 20:30
KenC
Just call me: Ken
 
Klang
Malaysia
+/-1/16 isn't bad. You can drill a bigger hole instead of milling slots. Save a lot of time & still worked perfectly. Just make sure the hole is smaller then your washer
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  #123  
Old Sun 29 December 2013, 21:06
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
My rails didn't have much bow but I had to elongate my holes 3mm because I didn't center the holes on my beams, I used a 1/8" pencil die grinder and carbide bit, took 30 minutes for one rail.
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  #124  
Old Tue 31 December 2013, 15:52
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
Straight X-Rails

I went to work yesterday and found that just about everyone else in the office had decided to take Monday and Tuesday off. I was just about the only one at work. I went ahead worked Monday, but decided to just take today off as well. More build time!

I went ahead and slotted the holes in my x-rails. To each bolt hole I added 1mm along the length of the rail and 3mm across the rail. This gave me enough play adjust the rail.

To align the rails I set one rail in place and tightened the two center bolts. with my string guide attached, I pulled each end into alignment and bolted down.

I then took the second rail, loosely attached it with the two center bolts, used the gauge bar to set the spacing and tightened the two center bolts. I then used the gauge board to set the two ends. The string was used to verify that everything was straight.

The rails were then removed and painted. I still need to drill holes for the proximity, stop block and of course attach the racks.


Tomorrow gantry fabrication starts.
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  #125  
Old Tue 31 December 2013, 16:22
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Cool! Progress!
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  #126  
Old Wed 01 January 2014, 05:07
KenC
Just call me: Ken
 
Klang
Malaysia
DB, I admire your discipline. I didn't have the patient to leave the gantry fabrcation until the rails are made.
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  #127  
Old Wed 01 January 2014, 15:50
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
Gantry/Y-Car Prep Work

I started prepping the gantry and y-car for welding today. I looked over the gantry plans and forum posts to get the exact location of the welds and the order. I took my grinder and cleaned all the areas where I will be welding. Next I wrote, in magic marker, the number order of the welds and an indication of the length.

Of course I also noticed that that I need to add some countersunk holes for the stepper hold down. I did not have have the correct type of screws. So those are on order. I decided to wait on the countersinking until I had the countersunk screws in. I want to verify the depth I need to cut before actually doing it.

On the same order from McMaster Carr I ordered the flat stock for the Z axis. I also realized that I will need to make a trip to the steelyard to get some 1"x2" rectangular tubing for attaching the plate.
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  #128  
Old Fri 03 January 2014, 10:00
IMMark
Just call me: Mark #119
 
Columbus Ohio
United States of America
I think you want to countersink those holes prior to welding?
I will leave it to the pros to verify.
Best of luck!
Mark
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  #129  
Old Fri 03 January 2014, 10:39
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
You are correct about that. I am holding off until I get the screws to verify how deep I want to counter sink.
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  #130  
Old Fri 03 January 2014, 20:53
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
Carrier Plate and Spider

When welding the tower carrier plates to the Y-car, I see two options.

1. Weld the plates to the Y- car, leaving a gap between the plates and the spider.

2. Bolt the spider to the carrier plates and pull in the sides of the Y-Car to meet the carrier plates and weld. The advantage of this method is I can get a tight fit between the spider and the carrier plates.

The gap is about 4mm in both cases.

My preference is option 2. I have not seen posts of anyone doing option 2, so I want to be sure that method would be okay.
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  #131  
Old Fri 03 January 2014, 21:52
Mrayhursh
Just call me: Hurshy
 
Riverview, Florida
United States of America
Thanks DB. Good info. This reminds me of an incident at work. My boss (head of engineering for a Fortune 500 company) was not to happy with my other boss head of machining and production. We were working on a new prototype spray foam system. The draft man drew up a spectacular set of plans for the structural base and outer metal housings. We received the parts and nothing fit. The two of them went at it for a couple of minutes and the machine shop boss said ok I will go talk to purchasing and have them order the $200K machine (1975 Dollars) to make the parts that he wanted. My other boss got a practical lesson in sheet metal. You don't specify sheet metal tolerances of .0001 you specify them in fractions and drill some holes during assembly to insure that they do meet. I know that methods have improved since then but sheet metal work is a little sloppy.
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  #132  
Old Fri 03 January 2014, 22:34
pblackburn
Just call me: Pete #98
 
South-Central Pennsylvania
United States of America
I did neither and only carefully measured and tacked, and tacked and tacked and welded all in the same relative direction to reduce warping so the pull of the steel was consistent and not fighting each other. The spider was a tight fit with only one bolt up less than 0.030" clearance gap.

One can argue engineering foul ups all day long when I can attest from many years of industrial maintenance that it is the engineer who is at fault not the product design. The design was just as they made it.....incorrect. Only something theoretically and practically designed with input from knowledgeable sources will render a good product. I have also worked with some great engineers that I have marveled at their ability to make what seems impossible....possible.

Point being, there is more than one way to skin it and fry it; yet the outcome is just as good. The outcome is the result of the time in preparation, thought and love put into the thing you are working on.
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  #133  
Old Fri 03 January 2014, 22:38
lonestaral
Just call me: Al #114
 
Isarn
Thailand
Send a message via Skype™ to lonestaral
The only problem with option 2 is that if you get a tight fit it leaves no room for shimming.
If you can ensure that everything will be perfectly square after welding then do it.
I would be cautious and do option 1.
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  #134  
Old Sat 04 January 2014, 04:01
KenC
Just call me: Ken
 
Klang
Malaysia
Option 1. Mr. Murphy is well & alive.
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  #135  
Old Sat 04 January 2014, 06:17
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
Look through the forum. Their are a lot of threads that cover welding up the y car. Threaded rod is what I recall being used to set the width as desired. If you use the spider and do not I want it to tight, add a few thin shims to setup a gap so the spider can be removed if needed easily. But 4 pieces of threaded rod and some nuts would be best ..... And a bunch of clamps.

If you look on the main page and go to MechMates already cutting, then scroll down the pages looking at the right side, you will see how many posts are in the threads. Start with the ones with more posts as they tend to have more details about their builds.

You will be amazed at what is here if you come at the forum from different angles.

Ways to search
1. From Main page by topic.
2. By number of posts in thread (as I mentioned above)
3. By member. (Click on a member and view statistics)
4. Of course regular search by title or post

I am sure there are more
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  #136  
Old Mon 13 January 2014, 20:41
darren salyer
Just call me: Darren #101
 
Wentzville mo
United States of America
Lets get this build wrapped up.
Ever since you teased us with a hint of using your MM to assist with an airplane build, all my free time is spent researching homebuilt planes.
I don't know about anyone else, but I'm intrigued and will want to see lots of pics...
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  #137  
Old Mon 13 January 2014, 20:58
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
LOL! Believe me I want to get this wrapped up too so I can resume my airplane work.

I made a little progress this weekend with cutting my y-rails and gantry tubes to length. But then I mis-drilled the nut plate. I could have used it, but the bolt hole locations would not have been symmetric. Since I need to go to the steel yard to get a few more items, I decided to hold off. Also, the counter sink I had was not 90 degrees and they do not carry them at the box stores or HF.

I know, excuses, excuses.

Good news is it looks like good weather this weekend, so I hopefully I can get the gantry and Y-car welded up.


If you look real close at the picture below you can see my horizontal stabilizer peeking out on the shelf above where all the cans are located.
On the shelf above that(not visible) is a botched stabilizer because I got stupid with my riveter. That was 4 months worth of work lost . It is not all fun and games when trying to build an airplane. As a scratchbuilder, I have made lots of scrap.

Just to give you something more positive to think about, the following link is what I will be using for my engine, http://www.flycorvair.com/



A few other things I could add about the picture above, in the container appearing just to the right of the door, contains the various plywood templates I have made so far. Not really visible on the shelf with all the cans and at the far right, is the beginnings of the center spar section.

Last edited by dbinokc; Mon 13 January 2014 at 21:02.. Reason: few more comments
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  #138  
Old Mon 13 January 2014, 22:11
Mrayhursh
Just call me: Hurshy
 
Riverview, Florida
United States of America
if you are interested in building a homebuilt aircraft check out Zenith CH750. It is a STOL and the company is in Mexico Missouri. I have a tail section built for the CH750. You are welcome to it.
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  #139  
Old Sun 19 January 2014, 13:35
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
Y-Car Test Fit

The y-car is welded up and the holes drilled in the gantry crosstubes, rail and nut plate. I had to take a few minutes to do a test fit of the y-car to the rails. It looks like the car came out flat and rolls nice. On to welding up the gantry.
Attached Images
File Type: jpg y_car_test_small.jpg (103.6 KB, 588 views)
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  #140  
Old Mon 20 January 2014, 17:39
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
Gantry Welded

Gantry welded and rolling. On first look, it appears to be square. All wheels resting on the rails nicely and rolls smooth.
Next weekend I will get it, the y-car and y-rails painted.
Attached Images
File Type: jpg gantry_small.jpg (91.6 KB, 560 views)

Last edited by dbinokc; Mon 20 January 2014 at 17:44..
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  #141  
Old Mon 20 January 2014, 18:10
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Looking Good! Looks like you're at the same stage as me. I'm all painted, y car done and z completed except assembly and currently wiring the control box (nearly done).
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  #142  
Old Sun 26 January 2014, 14:38
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
Painted the gantry and y-car this weekend. Also made the stop blocks for the rails. I forgot to order the stops for the gantry and y-car, so I am on hold for that. Also ordered the proximity switches, a 24V DIN power supply and relays.

I weighed my spindle and mounting block.
Weights were as follows(in pounds)
spindle mounting block 3
spindle 11

I have ordered the gas spring McMaster part number 9416K2 with a 20 pound force.

Last edited by dbinokc; Sun 26 January 2014 at 14:50..
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  #143  
Old Sun 26 January 2014, 15:13
Zouave
Just call me: Eric #115
 
Sacramento, CA
United States of America
Don't forget to add the weight of the Z-slide and stiffener, plus any dust collection accessories you might mount to it... 20lbs sounds okay, I think I went slightly higher for mine, but I have a PC 7518, not a spindle. Not sure how the weight compares.

Last edited by Zouave; Sun 26 January 2014 at 15:18..
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  #144  
Old Sun 26 January 2014, 15:33
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
I thought about the weight, but I think I am safe with 20. If not, then getting the next size up spring is only about $20 plus shipping.
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  #145  
Old Sun 26 January 2014, 17:41
darren salyer
Just call me: Darren #101
 
Wentzville mo
United States of America
I thought erring on the heavier side (30#) was a good idea, then I had to reorder a lighter spring. I believe your plan of attack is right on.
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  #146  
Old Sun 02 February 2014, 18:20
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
Slow, but moving forward.

Got the stops welded to the x-rails and the holes for the proximity sensors drilled as well. Cut the extra 6 inches needed for my racks on the x-rails as well as the rack for the z axis.
Plan to weld up the extra lengths on the x-rails next weekend. If that goes well I will do my final mounting/alignment of the x-rails, mount the racks and be able leave my y-gantry on the rails.
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  #147  
Old Sun 09 February 2014, 16:05
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
Got the stops welded on for the y-axis as well as the holes milled for the proximity sensor. I would liked to have painted, but it was below freezing and foggy today. Next weekend is supposed to be a bit nicer.

I also cut apart the mounts for the cable chains and did a test layout of the X-axis. Getting the mounting link into the cable chain was an impossible task for me. I finally just filed a small bevel onto one side of the pivot point to get the chain to slip over.

I took a look at the y-axis chain as well. I think I am going to have to weld an extension onto the lower supports. The radius of the chain is too great to have it lay flat and still be able to connect to the gantry tube.

Got a 4 day weekend coming up next weekend. Probably not enough time to get a first cut, but should make lots of progress.
Attached Images
File Type: jpg status.jpg (107.0 KB, 360 views)

Last edited by dbinokc; Sun 09 February 2014 at 16:08..
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  #148  
Old Sun 09 February 2014, 16:39
Tom Ayres
Just call me: Tom #117
 
Bassett (VA)
United States of America
Looks very good...
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  #149  
Old Wed 12 February 2014, 21:44
dbinokc
Just call me: DB #118
 
Oklahoma
United States of America
Plasma Cutter thoughts

I know a few builds have centered on a plasma cutter. I would like to do a dedicated plasma cutter, but really do not have the space.

What I was thinking about would be to build a pan that could be filled with with water along with a support grid for the metal to be cut. This would be placed on the table and the head swapped out for a plasma cutter head.

After the cutting is done, the water is drained from the pan and the pan removed from the table. I suppose the cutting could be done with the pan dry, but I think the water cuts down on dust from the cut metal.

It would not be as convenient as a dedicated plasma cutter, but would provide a way to get more uses out of my mechmate.
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  #150  
Old Thu 13 February 2014, 00:15
Fox
Just call me: Fox
 
Amsterdam
Netherlands
A lot of 'hobby' cnc people take this approach actually.
Hobby people cause it's just one of these things that works if you do your plasma once every few months or so. If you cut plasma more often you quickly get tired of swapping everything out, hence building a dedicated machine.But that could be the next step after your approach.

Ps. If you are going to do this it might be wise to pay extra good attention to proper grounding and shielding as plasma cutter are notorious for these issues. check some of the plasma build threads.
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