Handmade V-Rails - "JR Skate" has 4.5" grinder riding the rail
 

(This post was made in this thread before - it has deserved its own separate thread)


Gerald, it's amazing how minds on opposite sides of the world can think in harmony. How do i upload pictures to a post?

Gerald while you were brainstorming this passed week, i was too, here is what i came up with. I will try to upload some pics.

That's a beauty! Applause!

JR when I get ready to do my rails how about renting me the grinder for a week. You could start your own rental business!

Tremendous! I too would like to rent it!!! That is certainly better than anything I was dreaming about.

WOW!! There is allot of talent here.

Very nice work.

As the work continues! It took about 9 hours to cut, grind, and bevel the rails (2 pcs 12' and 2 pcs 8' rough lengths) and they came out even better than I expected (Gerald, the skateboard works great). The masking tape makes layout a lot easier, and if you mess up it's easy to remove and start over.

Beautiful
 

J.R.,

When you cut the rails, did you slide the rail or the cutter? Based on your setup, I'm guessing you slid the cutter.

Also, the angle grinder you made is absolutely beautiful. Seriously, are you interested in renting it out????

All the best,

Marc

Marc, you are right, it's the cutter that moves, the rail is C clamped to the main beam (makes a great work surface). I cut my main beam (7" channel) 1st, should have left it 20' long, would have worked a lot better as a work surface. The little grinder is hard to control when you first start on a rail, it's because the depth rollers do not touch until it's almost completely finished. I need to address this problem before anyone else uses it. Maybe it will be more user friendly by the time you start your MechMate.

Great stuff J.R.!

How much did you lose at the tip of each rail because of the skateboard's length? It's very important for folk to know that they must not cut the rails to exact length before shaping the V.

Like how you marked out the holes on masking tape. :)

In the US stock steel comes 20 feet long(+ around 2" extra). My MechMate cut dimensions are 52" X 100" (our mdf comes 49" X 97", I've been building custom cabinets since mid 1970, still don't know why 49", 97"). I cut the rough length of the rails X = 12 feet and Y = 8 feet + or - a little (that's about 12" extra on each end. My skateboard is 16" long, by the time it hit the stop I only had about 2" in the clear, passed the "finished end".

JR,
Do you have a dxf of the skate board plate?

Tom

Tom I'm sorry to say I don't. It's right from the head. It would have taken me longer to draw it than to make it.:D J.R.

J.R.

I'm building your "skate" tool to grind the rails. Gerald's way works, but I want to try your method. I think the time invested will be well worth it.

I have a few questions concerning the roller that rides on the vertical 1 inch leg of the rail. I've searched McMaster high and low for rollers close to yours. Where did you get yours? Was the shaft a press fit on the rollers? The cheapest roller I found had a 1/16 inch clearance between the bore and shaft (if I used a 1/4 inch Dia. shaft). Or, is it a non-issue.

The guide rollers are not a problem.

I'm putting my design and parts list on AutoCAD and will post a PDF file if anyone is interested.

Greg

I am sure I am not the only one who would appreciate the plans for the grinding skate.

Take Care,
Les

Greg my bearings were surplus I bought them 15 to 20 years ago for $.25 each from a tractor store. They have a 3/4" bore and yes they are a press fit. I knurled a 3/4" rod to increase it's diameter a little.
The 1" leg has to be 1 1/8". I will double check this.
The stud for the rollers that ride the sides need to be very beefy. It has an ecentric hole for the adjustment bolt.
If you need closeup pictures of anything let me know.

Thanks J.R.

Have to run, darn day job getting in the way again. :)

I'll work on it tonight.

Greg

Greg,
Have a look here, http://www.vxb.com/ I have purchased from here before for my mini mill spindle bearings and thought they were reasonably priced.

Tom

Tom,

Thanks. That's the site I was looking for. I like McMaster allot for service, but they are high priced. If I was to use McMaster rollers, my "J.R. skate" would soon be approaching the "snap-on" league.

Greg

J.R.

According to drawing M1 10 110 Rev A - the X rail is 2.5 inch by 1.0 inch for us on this side of the Atlantic.

Greg

that's correct but to use the same skateboard as mine you will need to increase that to 1 1/8". The bearings bottom out on the inside corner.

J.R.,

I'm going to keep it at 1 inch. Using the web site that Tom supplied, there are any width one could want.

I wanted to ask you, does your skate stay vertical or does it rock back and forth, perpendicular to the X rail when grinding? It looked like you had a very nice 45 degree edge on your rail.

Greg

Greg,

I'm not sure but it looks like J.R. might have doubled up the side bearings. I would think that the wider the bearing surface the more ridgid it would be (less chance for a rocking action), at least that is what I am seeing.

Tom

Tom you hit the nail on the head. It doesn't rock any when the side bearings are adjusted tight against the angle. I did use 2 bearings per stud, so about 1" (2-1/2" bearings) X 4 (studs) of metal to metal. If yours rocks use Gerald's suggestion and put an outrigger.

In my paper design, I'm using 7/16 inch wide bearings. When you look at a cross section of the rail (2-1/2 inch x 1 inch angle) there isn't much surface area. It obviously works since J.R. has produced very nice rails (J.R. did add 1/8 inch, but I can't believe that an 1/8 inch adds that much surface). I did off set the center of the 3/4 inch diameter shaft for the bearings. It should be a tight fit.

Let me know if i'm missing something. I have to order parts (haven't done so yet), so when I get my parts, we'll have another prototype.

Attachment 283

The "outrigger" I suggested before is the blue bearing:

JR,

Using an eccentrically drilled 3/4" rod for the bearings is a clever way to allow for tightening the jig onto the angle via cam action. I have two questions, however.

First, how do you intend to rotate the cams to equal pressure? Also, would it not be easier to have both bearings on one side of the angle use center bored rod and have cams on the other? This would make adjusting the entire skate, and the surface of the grinding wheel, to be parallel to the rail much easier.

Secondly, how do you intend to keep the bearings from riding up the rod toward the carrier plate as the skate is pressed down as it is moved along the rail (perhaps a second bearing stacked on top to fill the entire space under the carrier plate - this would have the added advantage of offering more support during the early grinding when the rail is square)? There is no washer/retainer of any type in the drawing. It would be possible to turn a taper on the rod (say 0.5-1^o) thereby creating a press fit, but this can be tricky as too much pressure can deform the bearing and cause it to malfunction.

Brian

I think I'll make the skate as is (aka - J.R.'s skate) and post results.

Its amazing how some people can design and fabricate in therir head. Not I.

On another note - My C-channels arrived yesterday :). Geeez, J.R. that C7x14.75 is 300 lbs (136 KG) by itself. You moved the partial table outside to the paint booth by yourself? I think I'll start calling you SIR (as in yes sir!)

Greg

First; Brian based on using the tool, having equal pressure does not seem to be an issue. Having all bearings adjustable makes setup a little easier, once you get it adjusted you leave one set alone as if they are center bored. Also being parallel doesn't seem to be important as long as you have enough extra length to get the wheel completely off the good piece.
Second; The bearings are pressed on the 3/4" rod(read earily post in this thread to see how this was done), they don't move. Remember the most important pass is the last one, anything extra should be done here.

Greg since I moved those sides by myself my wife said she thinks my voice is a little higher???:eek:

Here's my version of J.R.'s Skate (rail edge grinder).

I used 14 gage for the base plate for two reasons. First, it is easy to work with. There are slotted holes, and I don't have an end mill to machine these features. Instead I used a jig saw with a metal cutting blade. Second, 14 gage plate is what I had laying around the shop.

Because I used the 14 gage, there was allot of flexing. So I added 1/4 inch thick bars for stiffeners. These stiffeners were left overs from cutting the 2-1/2 inch leg of the angle down to 1 inch. Waste not, want not.

The bearings were stock from www.vxb.com. The other parts (handle, nuts, bolts, etc) were McMaster Carr.

I tried to fabricate this tool, so anyone without lathes, end mills, etc. could make one. The cost is resonable also.

Attachment 330

Attachment 331

Attachment 332

Ah! The proof of the pudding shall be in the eating! :)
(Looks good, but let's see if it works.)

If I were making the "JR skate", I would cut off the ends so the tips of the rails would be visible all the way to the rollers. Also, I would trust the handle screwholes in the body of the grinder to actually hold the grinder at the correct angle - can you tighten those hard into the (plastic?) body? I think I would shorten everything as far as possible so as to lose less unground rail length at the ends.

Yes, it does work fine. I'll post some pic's of the rail when I get time. (My weekend job is irrigating our alfalfa crop, geeez, I don't have enough to do :))

It rides the rail very nice and I don't think one needs to cut the ends off to the rollers. The plastic body of the grinder has brass inserts for the handles so it holds the grinding angle OK (not saying it couldn't be better )

Yes, there is some waste on the ends of the angle, approx 10 inches [254 mm]. I have not cut my 20 foot [6 m] angles yet. The waste will equate to about 4 USD [2 USD per foot for 2x2x1/4 inch angle).

Greg

It looks good, I hope it works as good as mine does. S/N 002 has been issued. Who wants S/N 003?

Not so fast with the S/N. Gerald has a good point. When I post pic's of a good rail, then I'll accept 002.

It may still require some mods / refinements. Something is not ridged. I don't have a consistent surface / edge on the 45 degrees.

Back to the drawing board. That Dewalt grinder with the plastic housing does flex at the connection points when grinding. How in the *%$# can Gerald see that and he's half a world away and I couldn't.

Learn and move on. I have a Ryobi grinder like the one used in the trash can example of the rail grinder. Its a newer model and the housing is different. I'll try something new with the other grinder or buy another angle grinder that will work.

Lesson learned - make sure your grinder has a metal housing for a solid connection. Time for a beer and a ball game.

Greg

Hi Greg,

Great job on the skateboard!!:) What model number bearings did you use?

I spent a lot of time looking for a good grinder to use for my skateboard and have found that most of them have either plastic housings or the handles are no longer perpendicular to the body of the grinder they are angled back. I had previously purchased this one from Harbor Freight but was unsure if I could make the front attach the way Gerald did on his. With your design I don't think it would be and issue.

http://www.harborfreight.com/cpi/cta...emnumber=31309


Hope this helps.

Greg M

Thanks Greg,

If I can't find a suitable grinder locally (slim to none), I'll order tomorrow night (If I do one more overnight shipping, my wife is gonna shoot me).

The bearings/rollers are P/N - R12ZZ (3/4 inch ID x 1-5/8 inch OD x 7/16 inch wd).

Attached is a partial parts list. Note that I used low head socket cap screws. Not allot of space. I would also go to a larger three-arm knob. The list is not complete, and I'll finish it some day.

Greg

Attachment 333

If you take a bit of flat bar, say 1" x 1/8" x 4" long, bend the last 1" at 45 degrees, erect that verically under the grinder, then hoseclamp the body of the grinder to that bent 45 deg. . . . . . ? That should attach the grinder at a 3rd point and steady it out.

Hmmm ... always the simple solution ... :)

Grinders are so inexpensive these days, I'll look in town tomorrow to see whats available, ....

P.S. - One more "move" on the irrigating tonight and up at 0500 for the last "move" and off to the day job. I must enjoy this :rolleyes: