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  #1  
Old Fri 28 August 2009, 16:14
Radishworks
Just call me: Mike #40
 
California
United States of America
Tips for Rail Grinding

I've successfully finished my rails and I've come up with a list of tips. I know some are already on the forum but I thought I'd put all my lessons learned in one post.

1. I used a Makita 4-1/2" 9557NB grinder. I've had this grinder for a few years and didn't care if it had a visit from the "magic smoke". I had to do a little grinding and add some extra holes to mount it (see image below) to the standard skate. But I'm happy to say its a tuff little grinder and still going strong.

2. I got the cut off disks from Harbor Freight, here: http://www.harborfreight.com/cpi/cta...emnumber=45430
I got them on sale for $4.99 (10 pack), but the regular price of $7.99 is pretty good too. I used about 2 disks for the long 97" in rails and about 1 disk for the 49" ones. I started with cut-off disks from Home Depot that were $2 each, those ones took 6 disks per long rail!

3. Cut outside, not in your shop! I know this has been said (thanks Gerald), but that first one was late and I had to try it inside, what a mess!

4. Buy the Skate Handles. OK, I looked at the materials list and thought, ahh... no need to give McMaster Carr another $14 I don't need those skate handles. My hands and fingers got pretty sore with no real good place to grab.

5. Wear gloves! After my finger touched the grinding disk for the 3rd time, I decided some good leather gloves would be a good idea. Gloves == good doh! :-).

6. I started with the table saw method (for the flat surface), and then came up with a better plan. I used a left over piece of the cross rail and a piece of 1" MDF and clamped the rail on them (see image below). This made a nice flat surface and I only had to re-clamp the long rails 3x and the short rails 2x. I highly recommend this method, my rails came out really nice and flat.

7. As said so many times on the forum, cut slowly and take your time. Back and forth, don’t cut like a table saw. Patients pays off for this part of the project.

8. Let the grinding dust build up on your flat surface until your cut is finshed. Then bush it off for that "final" pass. The clean plane makes that last couple passes nice and perfect by lowering the ginder ever so little.

Happy cutting, see pics below.
Attached Images
File Type: jpg DSCa_0004.JPSkate1.jpg (34.5 KB, 1822 views)
File Type: jpg Skate2.JPG (25.8 KB, 1817 views)
File Type: jpg Skate3.JPG (41.3 KB, 1820 views)
File Type: jpg Skate4.JPG (22.4 KB, 1819 views)
File Type: jpg Rail.JPG (52.5 KB, 1837 views)
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  #2  
Old Fri 28 August 2009, 17:12
jehayes
Just call me: Joe #53
 
Whidbey Island, Washington
United States of America
Thanks. I agree with your assessment of the Home Depot discs, I used about 15 to do all four rails (at $1.89 per disc). I wish I had heard about Harbor Freight.

I am now in the middle of grinding the angles and am finding it very slow going although the system works OK. Do you have any good tips for that part?

Joe in Washington State
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  #3  
Old Sat 29 August 2009, 08:42
Radishworks
Just call me: Mike #40
 
California
United States of America
I actually found grinding the angle part to be harder than the cutting, it actually too quite a bit longer job. My best tips:

1. I used thicker “grinding” disks (about 3/16” thick) for the angles.

2. Those height bolts on the skate that rub on the top of the rail need to be adjusted like by little to make the rail grinds deeper and deeper. I found spacing them with washers to change the height worked pretty well.

3. The best tip is to use some grease on the top of the rail where those bolt rub. I can really see why some people on the forum have posted pictures of skates that have rollers for the height adjustments. The raw bolts rubbing on the rail tops (without grease) don’t roll very smooth – the grease helps a LOT, but does make a bit of a mess.

4. Beware of the bolts that rub on the rails getting shorter, the rails ro wear groves in them, they need to be replaced several times.

Good luck!
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  #4  
Old Sat 29 August 2009, 10:08
jehayes
Just call me: Joe #53
 
Whidbey Island, Washington
United States of America
Thanks. I am having better success now. I also figured out about using washers; I have used two more in the back than in the front, slowly removing them one at a time as I grind.

I also decided to use round headed machine bolts with an allen key instead of hex bolts for the rub bolts. They seem to slide and wear better than the hex bolts.

The grease tip is a good idea that I will try today. I also found I had to clean off the accumulated grinding grit from the bottom of the skate (near the leading roller bearings) or it will seize up the rollers. Thanks again for your help. I will post a picture when I am done (maybe this weekend). Joe
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  #5  
Old Sat 29 August 2009, 10:16
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
It also important to get the bevel cutting action downwards, away from the top edge. This throws the sparks and grit downwards (mostly), but also avoids making a burr (ragged edge) where the bolt slides.
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  #6  
Old Sat 29 August 2009, 14:13
jehayes
Just call me: Joe #53
 
Whidbey Island, Washington
United States of America
Right. That is why I cut from left to right and have the front lowered and the rear elevated. I also shifted the left side of the upper plate inward and the right side outward as far as I could. That throws the sparks downward and backward (and, most importantly, away from me!) and leaves the cutting on the leading edge of the disc. There is still a slight accumulation of grit on the roller bearings that needs to be cleaned after every third or fourth pass. Thanks for all the good advice. Joe
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  #7  
Old Sat 21 November 2009, 08:37
Claudiu
Just call me: Claus #43
 
Arad
Romania
Hello

I´ve put some videos of cutting down the rails.

Have a nice weekend!
Claus
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  #8  
Old Tue 02 March 2010, 10:08
quadtech
Just call me: Prasad
 
Hyderabad
India
I found an interesting rail grinding jig from a post on another forum -





The main page is here -

http://www.backyard-workshop.com/pro...axis-rail.html
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  #9  
Old Tue 02 March 2010, 10:42
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
The comment on his "blog" about the flex in the alu is interesting.
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  #10  
Old Tue 02 March 2010, 22:08
Regnar
Just call me: Russell #69
 
Mobile, Alabama
United States of America
Claus, I would caution you to use eye protection. I speak from experience that you do not want a hot piece of anything melting to your eye. Its a painful trip to the Emergency Room. I am glad my medical is free because I dont even want to know what that bill would have been. Now I wear these http://www.wileyx.com/EcommSuite/Pro...1V&ItemCode=70 What is nice is they make a nice seal around the eye cavity and also allow for ventilation. I would also have done a face shield to.


Mike I was wondering how long your other rails took to make after you switched to the Harbor Freight disk?

Last edited by Regnar; Tue 02 March 2010 at 22:12..
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  #11  
Old Wed 03 March 2010, 12:42
oopz
Just call me: oopz
 
Stockholm
Sweden
Flex in Alu.. thats why I went back to metal..

Quote:
Originally Posted by Gerald D View Post
The comment on his "blog" about the flex in the alu is interesting.
The use of aluminium for building larger stands with several storeys at exhibitions, is most frequently done with aluminum profiles (beffy) like we use in DIY CNC, etc. Even with other DIY machines out there they see this problem flex when they escalate above 3-4 feet and above.

But when we (at the firm) constructed multi-storey buildings (to use at fairs in EU) with high security demands, we had to use specially designed metal solution at different places of the construction, just to "help the structure" that because of the to high flex point in aluminium profiles.. and the construction solution. So yes,in the blog you can read about the phenomena.

Aluminium profiles its a great "material" yes it is, I myself has as said in the head line went back to the basics and use metal. But as said Im not against aluminium. I have the opportunity to have "it" aluminium in-hose but still don´t start there. Im still going across the street for metal..

Off-topic I use Alumilite for making small parts, plus metal and Alumilite "combinded/melted" then machined to "strong parts"... (in the large format cameras world 12-24" and 30" size).

/oopz
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