So What Does One Do When They Don't Have a Decent Local Mechanic...?

[boogieman]

Let me try and explain mathematics to you.

The straight down the side rails is 180 or 0 degrees, it's a straight line. Now take the 0 degrees as your straight line and make a 90 degree turn to the end rail, now you're at 90 degrees. Ok now, if you draw a line straight out from the apex of that 90 degree corner, the left and right side of that center line would be consider a 45 degree angle, so 90 + 45 = 135 degrees and in a corner pocket that means both pocket miter angles are parallel to each other, same opening in the front of the pocket as it is in the throat of the pocket. So now if you add another 6 degrees to that 135 miter angle you end up with 141 degrees. Well, you can't set a chop saw to a 141 miter angle so then take that 141 miter angle and subtract that 90 degree turn at the end rail, that gives you a matching angle to the end of the rail, cut off at 90 degrees, follow me so far?

So, 141 degrees minus 90 degrees leaves 51 degrees, and that you can set on a chop saw. Want to check my math, put a quality protractor along the nose of the cushion, 0 degrees, angle it to match one side of your corner pocket, that reading right there will tell you what the pocket miter is, be it 45, 46, 47, 48, 49, 50, 51, 52, or 53 degrees. Now take that damn rail and put it up against the fence if the chop saw, cushion first, and see if you can't then see the miter angle cut at the end of the rail lining up. DON'T CUT the damn rail and cushions with the saw blade, cut it a little wide with a bandsaw, jig saw, anything else. Now that you have the excess removed, set up you 10" sanding disk, set your miter and down angles, and SAND TO FINISH LINE! WASH, RINSE, AND REPEAT!!!

When I did mine it was a little different from what's being done in this thread. I was fixing a butcher job that Olhausen did at their factory. Every left cut angle was a degree or two larger than every right cut. They had their saw or whatever they use set different on the left/right. I didn't redo the sub rails but used thicker facings and got the proper angle. Not really the "right" way to fix it, but I also wasn't willing to put new cushions on and put any more effort/time/money into a decent, but still furniture grade table. I used a table saw with a sanding disk.

A sanding disk in entirely the correct thing (not doubting RKC here, just seconding the advice that I took from him and other mechs on the forum). It allows you to really get everything precise down to the gnat's ass.

 

[realkingcobra]

Let's say you take a 5" pocket opening, and add 1/4' extensions. Everyone seems to think 5"- 1/2"= 4 1/2" pocket openings right? Well, wrong! The thickness of the extensions don't change, but what does change is the crosscut angle at the end of the extensions. A 2×4 cut off at 90 degrees is still 2x4 but if you measure the cut off end at a 45 degree cut it measures 2×6 basically because you're cutting the board at a longer angle. So on that bases, I calculate 2 extensions at 1/4" in each as 1/2" + 50% increase for the 51 degree miter changing the mouth opening by 3/4" therefore reducing the 5" pocket opening down to 4 1/4", not 4 1/2". So, extensions and facings are measured at their cross width, plus 50% for the total pocket opening reduction.

 

[The_JV]

DON'T CUT the damn rail and cushions with the saw blade, cut it a little wide with a bandsaw, jig saw, anything else. Now that you have the excess removed, set up you 10" sanding disk, set your miter and down angles, and SAND TO FINISH LINE! WASH, RINSE, AND REPEAT!!!

A sanding disk in entirely the correct thing (not doubting RKC here, just seconding the advice that I took from him and other mechs on the forum). It allows you to really get everything precise down to the gnat's ass.

Rest easy my friends. First thing I did this morning, (after my coffee) was run out to the local 'hobby-ist tooling store'.

I even accessorized with a cleaning block

 

[realkingcobra]

Rest easy my friends. First thing I did this morning, (after my coffee) was run out to the local 'hobby-ist tooling store'.
View attachment 622211
I even accessorized with a cleaning block

Make sure you cut a donut hole in the middle of the sand paper disks first before you mount them. The nut and washer won't tighten up and stay tight on top of the sand paper grit and WILL come loose and free spin until it finally stops.

 

[The_JV]

Make sure you cut a donut hole in the middle of the sand paper disks first before you mount them. The nut and washer won't tighten up and stay tight on top of the sand paper grit and WILL come loose and free spin until it finally stops.

Will do...

When I bought the various materials the sales rep pointed me toward a pre-punched sandpaper for the disk. Although it was the right diameter, it had only a 5/8" hole punched in the middle. Which doesn't take into account the washer. They didn't have anything more coarse than 120g in those pre-punched pieces anyway, so I opted for larger 12" sheets that I could trim down and make an adequate hole for the arbour/washer.

 

[The_JV]

I had actually made a mistake by using 39 (which is actually the outside angle) instead of 51, (inside). That greatly changes the resulting hypotenuse (answer 'c'), which is the value that directly effects the pocket opening.

I'm deep into procastination mode this morning so I had a go at sketching out the facing math in paint. Apologies in advance for the rough pic.
View attachment 622083

Sooooo....

Looks as though I had it right to begin with...lol The angle I should be using for my facing trig is indeed 39, not 51.

Lets image a line perpendicular to the rail in the above pic starting at the blue arrow. We will call that the '90 degree line'. Now exactly like RKC has explained. The angle of the rail miter is 51 degrees from that '90 degree line'. Makes total sense, but here's the thing when it comes to calculating the cross sectional width of the facing material at the miter. You don't use 51 degrees again. You use the remaining angle to get you to 180.

So, 90+51=141, 180-141=39. The number I should have, and did originally used in the right angle calculator is 39. Which means all my original math is correct. Looks like I need to update that post again....lol

...or I can just stop running around in circles and do it the way RKC explains it a few posts up....lol.

 

[TrxR]

I got a quick question? Why 141? Aren't there some rules that require 142-143 (WPA Ithink) ? Also what's the recommended angle for the side pocket? And are you reducing the side pocket by the same amount as the corner?

This is a very interesting thread. I'm hoping to buy a table this summer and am not against a good used gold crown if one came up locally and my father is a cabinet maker so this would be something I would like to takle if one came up. Otherwise I'm looking at a new Diamond.

 

[realkingcobra]

I got a quick question? Why 141? Aren't there some rules that require 142-143 (WPA Ithink) ?

This is a very interesting thread. I'm hoping to buy a table this summer and am not against a good used gold crown if one came up locally and my father is a cabinet maker so this would be something I would like to takle if one came up. Otherwise I'm looking at a new Diamond.

The BCA specs were wrote by a table manufacturer not the BCA, so who cares really. Second, Diamond in their efforts to create a standard size pocket openings on professional pool tables, they not only decided on 4 1/2" corner pockets and 5" side pockets, but we also had to take a look at the pocket openings in as far as the miter angles and down angles which effect how the pockets react to the balls being pocketed. It was decided that the 141 miter angles in the corner pockets played in such a way that they neither rejected well hit balls, nor accepted balls that really shouldn't get pocketed. Less than 141, getting to easy, greater than 141balls hit a little to hard get rejected. Then the down angle was determined to take out just enough speed of the balls being deflected downward towards the slate that it would give the ball a better chance of deflecting deeper into the throat of the pocket, making the balls with the deeper shelf, that down angle isn15 degrees. On a GC for example with the same miter angles and pocket opening, 15 degrees down makes the pocket play to soft, to easy, so a GC down angle angle better matches the Diamond deep shelf play ability if the down angle is reduced to 13, or even 12 degrees down, thereby increasing a slight bit more resistance to pocketing the balls to easy.

 

[TrxR]

The BCA specs were wrote by a table manufacturer not the BCA, so who cares really. Second, Diamond in their efforts to create a standard size pocket openings on professional pool tables, they not only decided on 4 1/2" corner pockets and 5" side pockets, but we also had to take a look at the pocket openings in as far as the miter angles and down angles which effect how the pockets react to the balls being pocketed. It was decided that the 141 miter angles in the corner pockets played in such a way that they neither rejected well hit balls, nor accepted balls that really shouldn't get pocketed. Less than 141, getting to easy, greater than 141balls hit a little to hard get rejected. Then the down angle was determined to take out just enough speed of the balls being deflected downward towards the slate that it would give the ball a better chance of deflecting deeper into the throat of the pocket, making the balls with the deeper shelf, that down angle isn15 degrees. On a GC for example with the same miter angles and pocket opening, 15 degrees down makes the pocket play to soft, to easy, so a GC down angle angle better matches the Diamond deep shelf play ability if the down angle is reduced to 13, or even 12 degrees down, thereby increasing a slight bit more resistance to pocketing the balls to easy.

Can the down angle be changed when extending the subrails?

Also what angle is recommended for the side pockets?

Thanks, you wealth of info is greatly appreciated.

 

[coolidge]

Speaking of other people who like to spend your money (cough) RKC (cough)

 

[realkingcobra]

Can the down angle be changed when extending the subrails?

Also what angle is recommended for the side pockets?

Thanks, you wealth of info is greatly appreciated.

Yes, thats when you set the miter angles and down angles, after the rails have been extended what kind of table are you talking about, I have no idea.

 

[realkingcobra]

Speaking of other people who like to spend your money (cough) RKC (cough)

View attachment 622428

What, only 1??

 

[TrxR]

Yes, thats when you set the miter angles and down angles, after the rails have been extended what kind of table are you talking about, I have no idea.

It would be a gold crown if I can find one local.

 

[realkingcobra]

Can the down angle be changed when extending the subrails?

Also what angle is recommended for the side pockets?

Thanks, you wealth of info is greatly appreciated.

102 or 12 degrees, all depends on how you're looking at it but on a chop saw with a sanding disk, its 12 degrees miter and 13 degrees down angle

 

[The_JV]

Yes, thats when you set the miter angles and down angles, after the rails have been extended what kind of table are you talking about, I have no idea.

So when determining the down angle. Is there more aspects to consider than just the shelf depth from point to point...?

I finally have my miters laid out and need to figure out my down angle. My thought was to measure shelf depth and compare that number to the minimum which seems to be 12 degrees (GC) and the maximum of 15 degrees (Diamond).

Again, the goal is to be unforgiving but fair.

 

[The_JV]

Speaking of other people who like to spend your money (cough) RKC (cough)

View attachment 622428

Very nice... I ended up with a much cheaper version, but probably ended up costing me the same. I didn't buy from the cheapest place.

It's a shame I don't have my old school "pattern maker's" together as I could have used it for this rail work with far greater ease. This one isn't mine, I have the same model beast sitting for a motor rewind in my garage.

 

[coolidge]

Very nice... I ended up with a much cheaper version, but probably ended up costing me the same. I didn't buy from the cheapest place.

It's a shame I don't have my old school "pattern maker's" together as I could have used it for this rail work with far greater ease. This one isn't mine, I have the same model beast sitting for a motor rewind in my garage.
View attachment 622505

Is that an Oliver?? Those are beasts. Alas as I'm approaching 60 years of age I opted for the Sawstop safety feature. Really missing the capacity of a 12 inch blade though.

 

[The_JV]

Is that an Oliver?? Those are beasts. Alas as I'm approaching 60 years of age I opted for the Sawstop safety feature. Really missing the capacity of a 12 inch blade though.

Wadkin PK... It takes an 18" blade but I can't recall off hand what the cut capacity is.

I didn't realize it when I grabbed that pic off google, but that one has an extended slide. Mine is the standard model.

 

[tomatoshooter]

I opted for the Sawstop safety feature.

I've never personally tested one but the demonstrations are impressive. Table saws are pretty dangerous. Even with the pusher stick, you are still moving towards fast moving sharp things.

 

[dendweller]

I've never personally tested one but the demonstrations are impressive. Table saws are pretty dangerous. Even with the pusher stick, you are still moving towards fast moving sharp things.

Pretty sure it's expensive to test, my brother has one, said if you put a hot dog in it it stops, problem is, the blade is sacrificed. Worth it to save a finger, not the hot dog.