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  #91  
Old Thu 13 November 2008, 11:22
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Kray posted some YouTube videos yesterday.
http://www.youtube.com/watch?v=rraFsgnuh5s
http://www.youtube.com/watch?v=NbhrYvy2wFU
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  #92  
Old Thu 13 November 2008, 21:15
kn6398
Just call me: Kray
 
Fort Worth
United States of America
Gerald you are quick I was going to post it here but you beat me to it.
I was trying to figure out what the links was but it was getting late.
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  #93  
Old Thu 13 November 2008, 21:29
kn6398
Just call me: Kray
 
Fort Worth
United States of America
It took me about 8 minutes to grind one side of the 10ft rail on the first video. It was getting dark outside and I didn't want to disturb the neighborhood so I stopped and continued the next day.
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  #94  
Old Thu 13 November 2008, 22:54
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
After grinding those rails, are there any tips you could pass on to the folk that are nervous about doing it?

Good videos and pics!
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  #95  
Old Fri 14 November 2008, 20:41
kn6398
Just call me: Kray
 
Fort Worth
United States of America
Thank-you for the compliment.

What work really well for me was using a good grinder and changing out the disk often for faster grinding. Change out the disk once the leading edge of the disk wear out, you will notice the spark will start to spark in the middle of the disk instead of the leading edge. At that moment the disk will glaze and grinding will be slooow. I read in the forum someone mentioned to adjust the front slightly lower than the back to keep the leading edge in contact with rail when that happen but it was more convenience for me just to change out to a new disk. I use two discs for one rail. The first two short rails it took me all day because I was afraid I might push the grinder to hard. I use the back and forward motion but once I got comfortable I just lightly push the grinder forward without the backward motion for about a foot and pause for a couple of second and continue on forward. It seems to grind faster that way. On my last rail in the video my confidence level was really high I just lightly push the grinder forward without stopping and it took me 8 minute to grind down one side of a 10ft of 12ft rail. I stopped in the video because the disk was wearing out and it was getting dark and I didn’t want to disturb the neighborhood. The grinder was really hot when I stopped if I had used one of the cheap Harbor Freight grinder I would of burn it again. If I can do this anybody can too.
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  #96  
Old Thu 18 December 2008, 08:31
Delamination
Just call me: Travis
 
Delavan, WI
United States of America
I finished cutting the rails yesterday. Light cuts at first, then heavy cuts as was suggested. Worked quite well, along with a few screwdrivers to pry the cutoff away from the rail and prevent binding.

Dust everywhere. But I brushed some of it into a old plastic 1 gal ice cream bucket. The fine grindies nicely show flux lines from a few hard drive magents placed underneath,
Attached Images
File Type: jpg P1030815-s.JPG (65.2 KB, 2045 views)
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  #97  
Old Sun 21 December 2008, 19:55
myozman
Just call me: Mike #16
 
Demotte,IN
United States of America
Gantry and Y-car rolling

I was really hoping to complete more this weekend, But between the freezing rain and loss of electric and now high winds and temps around zero.

Anyway, I hookrd up the generator at the house and one down at the shop. Shop is heated with wood and kerosine(torpedo heater). I managed to get some things done, just slow when it's cold.

I attached rails, welded gantry, and set the y-car. What a great feeling getting the gantry and y-car to roll smoothly. I lucked out and my gantry sat right down on the rails, no adjustment. I took the advise of others and welded it on a tablesaw.

Can't wait to finish the build. It rolls so smooth for being such a big heavy piece of steel. I think I'm a little short on my X cable chain, so I'll have to order more. I also have to get the shielded cables and control enclosure.

Here are a few pictures of the progress.

MIKE
Attached Images
File Type: jpg Gantry1.jpg (156.8 KB, 2051 views)
File Type: jpg Gantry2.jpg (145.1 KB, 2045 views)
File Type: jpg Gantry3.jpg (137.7 KB, 2045 views)
File Type: jpg Gantry and Rails.jpg (139.2 KB, 2041 views)
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  #98  
Old Tue 23 December 2008, 21:42
Delamination
Just call me: Travis
 
Delavan, WI
United States of America
I have finally gotten to the point of grinding the angles on the rails. Took me much longer (and more trips to Lowes and Ace) than I was expecting to get the skate assembled.

Welding nuts for the height adjustment bolts worked great, but I was having trouble spacing the grinder to set the grinding wheel at a good location to engage as much of the bearings as possible without bottoming out on the angle iron's fillet. Finally got it right and zing! bevels a-plenty.

Some things that were definitely helpful:
1. Clean off all the mill-scale. The bearings dont bind up then.
2. A little oil for the height bolt to slide on made movement smoother.
3. Clean up the 45 degree corners with a file so the v-wheel rolls smoothly.
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  #99  
Old Wed 24 December 2008, 14:13
Jayson
Just call me: Jayson #18
 
Horsham
Australia
The next most dreaded part of the build was the rail making. Now I know that many of you have said that it is not hard but until you do it yourself you can just not appreciate how easy it actually is. The angle for the x rail that was supplied was not as thick as I requested but decided to use it anyway, mainly because I was sure that the process would not work and I would end up buying linear rails. Well the process was so easy and went so well that I have a slightly under spec rail but I am sure it will be fine. I have bolted the rail down at centres of 120mm. The reason for this was that is the spacing required for the linear rail that I may have required oh and it adds extra support for the thinner rail



The rail cutting was very easy and from reading some other posts I think that I may have been very conservative with the rail cutting. I used a total of 4 disks for all the rails. I did use very light cuts and was ever mindful that the angle grinders usually do not survive a Mechmate build. My angle was 2 1/2 inch on both legs so I could not use the whole disk as the skate plate hit the rail before it was totally cut through once the disk wore a bit. If I had used differed rail I may have gotten away with 2 disks I think.

Christmas is underway here in Australia so I will have to go now, I will give an update in a few days when I get time to get back to the machine.

Cheers to all.

Its time to enjoy some food...
Jayson
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  #100  
Old Mon 26 January 2009, 20:53
jhiggins7
Just call me: John #26
 
Hebron, Ohio
United States of America
Yesterday I cut the steel into manageable pieces so I could carry them to my backyard where the workshop is. Good thing I got them off the driveway and inside. It's raining today.

Attachment 3476
Here, I've got the first piece of angle ready to cut-down.

Here's the Mikita Metal Cutting Saw with the jig I made to guide the cut. A little about the saw. It's the Makita 4131. When the discussion about Metal Cutting Saws was raging on the forum and the discussion turned to the Mikita saw, I happened to see it on Amazon for $140 with free shipping. I bought it. I'm afraid it's about twice that now.


I made a wider base. The one it came with was only about 4" wide. I made two guides to attach to the base. The one on the right in the picture is fixed and held with small clamps at 28 mm from the blade. The one on the left has springs between the guide nearest the blade and the fixed piece furthest from the blade. The springs help hold the fixed guide on the right tight against the steel. Good thing I used the springs and not just two fixed guides. The steel width varied nearly 1/8th inch.

The cutting went very well. It only takes about 5 minutes to cut the larger pieces. I cut them at 28.5 mm to allow for clean-up. After cutting them down, I used the belt sander to smooth them. It only took a lite sanding to get them smooth. I only took off less than .25 mm and they were smooth.


I'm sorry these pictures are a little fuzzy. I was trying to show the forum how the Metal Cutting Saw cut. I'm afraid I didn't do too well.

I started the bevel grinding. Here's a picture of the JR grinding skate. You can see that I've added a handle mount. I used the handle that came with the grinder. This grinder doesn't have a top hole for the handle. So, I drilled and tapped a small piece of 3/8's steel to fit the handle. I welded that to another piece that I shaped and drilled to fit on the standard skate. I considered welding it at 45 degrees to the mounting plate, but after trying to see how it would feel, I decided on 90 degrees. It does a good job.


You'll note that I'm using a Skill grinder. My DeWalt was going to require a lot of modification to the standard skate. I found this Skill grinder at Lowes for $29.95. It is almost a perfect fit for the skate. It's 6 amps. I figure if it fails, I can take it back. It's guaranteed for 1 year.

Just a note on equipment casualties...I have an older (maybe 10 years) Skill belt sander. It died during the sanding. I really wasn't pushing it. I think it's time had just come. I hope that's my "right of passage" and I don't have to burn up a grinder. Had to finish up with the Porter Cable sander.

Administrative note: I guess there's a limit of 5 photo's per post. I was trying to show 6 (rail after cutting and before sanding) and strange things started happening. That's okay, the photo was kinda fuzzy. If someone is really interested, I'll try to get a better set of photos to show the effectiveness of the saw.

Regards,
John
Attached Images
File Type: jpg The saw, top view.jpg (117.4 KB, 2029 views)
File Type: jpg All sanded ready for grinding.jpg (106.4 KB, 2019 views)
File Type: jpg Grinder skate.jpg (107.4 KB, 2021 views)
File Type: jpg Rail ready to cut resize.jpg (112.3 KB, 2019 views)
File Type: jpg The saw.jpg (117.4 KB, 2025 views)
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  #101  
Old Mon 26 January 2009, 23:55
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by jhiggins7 View Post
. . the Makita Metal Cutting Saw with the jig I made to guide the cut. . . . . I made a wider base. The one it came with was only about 4" wide. I made two guides to attach to the base. The one on the right in the picture is fixed and held with small clamps at 28 mm from the blade. The one on the left has springs between the guide nearest the blade and the fixed piece furthest from the blade. The springs help hold the fixed guide on the right tight against the steel. Good thing I used the springs and not just two fixed guides. The steel width varied nearly 1/8th inch..
You learnt a lot from us guinea pigs! I made the mistake of handing the saw and the rails (for 5 big tables) to one of my staff and told him to get on with it. At the end of the day he was wandering off the line. A spring loaded guide would have prevented that.
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  #102  
Old Tue 27 January 2009, 22:15
jhiggins7
Just call me: John #26
 
Hebron, Ohio
United States of America
Update...finished grinding the rails. Whew, that's a job! Glad it's done! It took roughly 8 hours of grinding. I ground 40' of rail.

First of all, the $29.95 grinder got the job done and is still RUNNING. I had a scare about half way through. I adjusted the bolts to cut deeper and I set the cut too deep. So I was grinding too aggressively. The grinder started to smoke! But, it must NOT have "released the Magic Smoke," because it kept working. I let it cool down, reset the depth and worked with the grinder the rest of the day.

Lesson's learned:

1. Don't be too aggressive on the grinding, it smokes grinders.

2. I found that I got the most controlled grinding by letting the grinding wheel PULL the skate along the rail. My job was to prevent the skate from going too fast and thus skipping a part of the grind and holding the grinder down on the rail. When I pushed the skate against the direction of the grinding wheel, I got more aggressive cutting, but it was NOT uniform...and it was HARD WORK! Just be patient and let the grinding wheel do the hard work.

3. Also, as someone else already mentioned, by letting the grinder move quickly across the rail, everything stays cooler. Don't rock it back and forth. The grinder stays cooler because it's not working as hard. The rail stays cooler because you're not sitting in one place grinding away. Also, I suspect, but don't know, that since you are moving quickly down the rail, the grinder is constantly encountering and throwing off "cooler" chips and just like in other kinds of cutting, bigger, cooler chips are a good thing.

Question: I noticed after finishing the grinding that a light hand sanding of the ground surfaces removed the grinder marks making the rails look more like they had been "machined." I haven't seen any mention of this idea...at least I don't remember it. Is there a problem with lightly hand sanding the rails? I don't think it would change the dimensions at all.

Regards,
John
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  #103  
Old Tue 27 January 2009, 22:50
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by jhiggins7 View Post
Question: I noticed after finishing the grinding that a light hand sanding of the ground surfaces removed the grinder marks making the rails look more like they had been "machined." I haven't seen any mention of this idea...at least I don't remember it. Is there a problem with lightly hand sanding the rails? I don't think it would change the dimensions at all.
The light hand sanding is perfect. We sometimes even drag a file across a rail that is roughly milled (draw filing). Strictly, this does change a dimension somewhere, but by such a tiny amount that you won't notice it. Bolting the rails down makes much bigger changes in the dimensions than a bit of sanding. The smoother the rail, the cleaner it stays.
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  #104  
Old Sun 01 February 2009, 21:37
DenisCasserly
Just call me: Denis
 
Vancouver
Canada
rail grinding question

Hi everyone,
I cut and began grinding my rails this weekend. Would anyone care to advise on the width of the flat on top of the ground V profile? On my first rail I got between .060" to .085" width. Is the width of the flat critical? It looks like the Superior Bearing wheel has a flat about .010" in width between the V flanks and I assume rail flat has to be wider that .010" or it will lose contact with the flanks.
The grinding slowed down after awhile, and I could see that it just wasn't cutting at the same rate, - is that caused by a glazed wheel? Only remedy is a wheel change?
I was unable to locate the Pferd cutting discs anywhere but I did manage to rip 40 feet of angle iron with 4 Tyrolit .045" thick discs. I pulled the offcut back just before cutting through because the kerf was closing and grabbing the wheel.
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  #105  
Old Sun 01 February 2009, 22:50
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
The Superior Bearing wheel actually has a radiused notch in the root so that it will clear a sharp 90 degree rail without any flat area. (You can test your bearing wheel on a "sharp" piece of iron).

The glazed wheel effect has been mentioned a few times. Simplest solution is to change the disk. To slow the rate at which the glaze forms, tip the skate so that the tip of the disk does most of the work.

Thanks for for the feedback on the Tyrolit disks. Can you give us a type number for that disk?
Catalogue: http://www.tyrolit.com/dataarchive/d..._pk2008_gb.pdf
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  #106  
Old Mon 02 February 2009, 17:43
DenisCasserly
Just call me: Denis
 
Vancouver
Canada
tyrolit cutting disc

Hi Gerald,
thanks for the info on tipping the grinder and the spec on the bearing.
Here's what is printed on the Tyrolit cut off disc:
TA60P-BFXA
STEEL
TYPE NO. 384142
4-1/2, .045 , 7/8"
SECUR EXTRA TOP

cheers
Denis
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  #107  
Old Mon 02 February 2009, 23:14
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Thanks Denis. From their catalogue, that is one of their "Premium" disks. Their Standard or Basic disks would probably not perform as well. Just mentioning this so that folk don't grab the first Tyrolit (or Pferd) they see on the shelf without checking the numbers carefully.
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  #108  
Old Sun 22 February 2009, 19:05
Sherman McCoy
Just call me: "Krasch"
 
Portland,OR
United States of America
Showing my best side- Welding the table

We made an honest attempt to cut the rails with the rotary grinder and were not happy with the results. The thin blade tended to "float". Checking tomorrow to see what laser cutting goes for. Any price will be a good price, because we couldn't even cut a straight edge on 3/16ths angle iron.
Undaunted, we moved on to the next item, welding the table w/cross supports, where we had considerably better luck. A 90deg clamp helped immensely in squaring everything up. Now we just have to figure the best way to bolt the table to the X-beams.
Attached Images
File Type: jpg Table1.JPG (100.1 KB, 1924 views)
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  #109  
Old Mon 23 February 2009, 19:56
Sherman McCoy
Just call me: "Krasch"
 
Portland,OR
United States of America
Plasma cutting - not the way to go

OK, so I call a metal fab shop referred to me by the steel dealer, he quotes me $75 to cut my rails, and I'm thinking, "Bob's my uncle", problem solved. I strap the rails to the top of the Subaru, and trek 40 miles to the middle of nowhere to drop off my angle iron. They've got a nice reception area with all these nice laser cut parts, how hard could it be to cut some rails?
Apparently pretty hard. I told them I was going to be using the edge they cut to run bearings on. They said "no problem." I didn't see a bandsaw or a diamond tipped anything anywhere in their 10,000 sqft shop, which should have been my first clue. On my return 2 hours later I look at my warped, butchered rails and I was speechless. I knew I was in deep kimchee when the owner starts off the conversation with, "this is the problem." I really think I could have done better with a handsaw. I still have hope(although very little change left after this mistake).I'll know if they're salvageable when I take them to the knife grinder to see if he can fix them.
I'm starting to understand why so few MM's have actually been completed. I think I'll drop down and do something like bolt together the skate. Now THAT (I think) I can accomplish.
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File Type: jpg plasmacut.JPG (80.7 KB, 1926 views)
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  #110  
Old Mon 23 February 2009, 23:38
Alan_c
Just call me: Alan (#11)
 
Grabouw (Western Cape)
South Africa
Send a message via Skype™ to Alan_c
I think in excess of 25 complete running and cutting Mechmates is not "so few" however, try the skate is has worked for many of us and can produce amazingly accurate results - if one has the patience to spend a few hours it takes to do the job properly. I achieved a maximum variation of 0.2mm (0.008") over the length of my rails which were up to 3m long (118"). No flexing disks or divots throughout the whole process.
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  #111  
Old Tue 24 February 2009, 00:02
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by Sherman McCoy View Post
We made an honest attempt to cut the rails with the rotary grinder and were not happy with the results. The thin blade tended to "float".
Maybe I havn't made it clear enough that one needs to make very light cuts at the beginning, to establish a groove, before piling on the pressure. Under these conditions, I cannot understand why you got "float". Can you maybe think of the reasons it floated?
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  #112  
Old Tue 24 February 2009, 07:33
J.R. Hatcher
Just call me: J.R. #4
 
Wilmington, North Carolina
United States of America
Send a message via Skype™ to J.R. Hatcher
Gerald and Alan, I agree 100% and would like to add ........

A few suggestions:
1. The finish surface will only be as good as the surface the grinder was sliding on (keep it clean during the process) and how well it was clamped down (C or G clamp every 12").
2. Keep the grinder moving, if the metal gets too hot it glazes the wheel and it will stop removing metal.
3. When the wheel starts to cut through you need to start climb cutting only (saves the wheel)
4. When finished, if you are not satisfied with the surface put a new 1/4"+- thick wheel on the grinder (it won't flex) and make several light runs back and forth across the top until you are satisfied. Note: As you continue with steady pressure on the grinding it will take off the high spots until it's not cutting anything.
5. As you are grinding the 45 degree angles keep both sides equal or about the same all the way down. Leave the flat somewhere between 1 and 1.5 mm.
6. Always wear safety glasses and breathing protection ........... NOW GO MAKES SOME SPARKS.
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  #113  
Old Tue 24 February 2009, 10:26
Sherman McCoy
Just call me: "Krasch"
 
Portland,OR
United States of America
This is what dirt bikers call a "racer's bend"

Alan, you, Gerald, and J.R. are my inspiration. Thanks for all the helpful input. Those tolerances you've achieved are absolutely amazing. I'm going to redouble my efforts and not report back until I have made some forward movement.
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File Type: jpg Plasmacut2.JPG (77.3 KB, 1942 views)
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  #114  
Old Tue 24 February 2009, 11:32
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Krasch, glad we didn't scare you off!

That last banana rail looks usable. If clamps will pull it down flat, the screws at 8" centers will do the same.
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  #115  
Old Tue 24 February 2009, 13:58
HomeMadeCnc
Just call me: Tim
 
Calgary, Alberta
Canada
I have the same issues with my rails. A little fine tuning required!
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  #116  
Old Fri 27 February 2009, 00:16
wheelygood
Just call me: Steve
 
Auckland
New Zealand
A few more photos.
Chewed through lots of Dia 125 x 1 discs, Y axis 1830 and X axis 3800. My angle is 60 x 60 x 8mm thick. I opted for 8mm because it was a much better shape angle that the 6mm version.
I went for a 3 legged angle grinder carriage, tried 4 legs but 3 felt smoother to push around. I`m not sure if anyone has tried pulling the grinder into the cut as I did but I found it easier.
My main X axis beams have 6 pieces of 50 x 5mm flat bar tack welded along the length to stop any resonate vibration.
I have built a concrete feed arm for a Million $$ concrete pipe spinning machine in the past and the 300 Channel arm picked up a nasty vibration and the flat bar fixed that.
Has anyone had issues with vibration or a ringing noise on their MM?

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  #117  
Old Sat 07 March 2009, 17:37
HomeMadeCnc
Just call me: Tim
 
Calgary, Alberta
Canada
Well a few steps forward. Still have to put the angles on the rails and paint them. My angle iron was 3 x 3 so I made a low tech skate that worked well. Will drill the holes for the prox sensors later as well. More to follow. . . . .
Attached Images
File Type: jpg skateWEB.jpg (44.5 KB, 1720 views)
File Type: jpg cuttingWEB.jpg (41.7 KB, 1720 views)
File Type: jpg toprailWEB.jpg (40.2 KB, 1730 views)
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  #118  
Old Thu 12 March 2009, 18:26
HomeMadeCnc
Just call me: Tim
 
Calgary, Alberta
Canada
Half way done grinding the rails. That's one nice jig, thanks Gerald.
Attached Images
File Type: jpg GrindingtheRailWEB.jpg (60.4 KB, 1744 views)
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  #119  
Old Wed 25 March 2009, 21:33
astrolavista
Just call me: Rene #29
 
Winnipeg, Manitoba
Canada
An update....

Got my X & Y Rails done, ran into a little snag with the Y rails but reading in the forum - I found the solution. One rail was .5mm taller than the other, so before I ground the V detail I used a thick grinding wheel to remove the extra .5mm.

THe skate worked awesome, one thing though, I had not even though of - "Its designed for 4.5" grinding disks" I had a stack of 5" disks that I thought I could use, but when grinding the v detail the 5" disk hit the "top of the bottom" of the angle iron before the skate's adjustment bolts hit the rail. I ran out and got the proper disks and it worked like a charm.

I was waiting for the old Bosch to go up in smoke after so much cutting and grinding, but it hung in there. I've had it for about 20 years its cut ceramic tile, biscuit slots, 2 hot rod frame builds. Like a Timex.. What a mess in the garage though, best to do the rail grinding process out side - the weather here did not co-operate though - too cold.

I did notice however that I could "hear" the wheels on the rails, Ifigured that the ground V surface was a little rough so I gave the V profile on the rails a light sanding with some 100 grit sandpaper to polish them up a little and it rolled alot smoother.

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  #120  
Old Thu 26 March 2009, 01:49
Kobus_Joubert
Just call me: Kobus #6
 
Dalview
South Africa
Send a message via Yahoo to Kobus_Joubert Send a message via Skype™ to Kobus_Joubert
My Bosch grinder look just like that....I killed 2 cheap types....gave them back to where I bought it so it did not cost me a cent. I wanted to SPARE my Bosch but in the end finishing my rails with the Bosch...GREAT MACHINE
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