Keystone Cut Tile Radius Measurements

[ceramictec]

Hey all, I called Jack (Hamilton) earlier today to ask him about radius measurements since he talked about it on another thread, but he was driving and couldn't talk much since Cali has a new headset law.
told me it was probably good to post a thread asking for help.

so for all you "good" mathematicians out there.....

I have a radius/circle in a bank foyer I need to figure out how much to cut off the
top & bottom of the tile to make a keystone so 60 tile will make this radius/circle.

I'm finishing another job now and was trying to cut these and do a dry layout in my driveway but cant since it would be difficult and time consuming to place each one to fit and mark. so I'm at least trying to figure out the measurements for this so I can make a jig and cut them all prior.

there are 60 tile needing to make this circle.
each tile is 11 3/4"
grout joints will be 3/16" to 1/4"
inside radius is 8'-6"
outside radius is 9'-6"

they have a nail at the center of the lobby already and they built the soffit above off it.
I will use it and draw a inside and outside line with those measurements and lay the 60 keystone cut tile in it.


help?!?!

[crete51]

brian inside circumference is 3.14x 17-0 =53.38 or 53-4 1/2 inches divided by 60 tiles =10 5/8 nches tight 1/8 mor off each side for grout =10 3/8..tiles now 11 3/4 so 11/16 off each bottom side of each tile................................ top circumference is 59.59 feet divided by 60 tile = 11 7/8 inches tiles are 11 3/4 inches.... pretty close..so each tile 11/16 at bottom to nothing at top on each side... still might want to try a portion in the drive way

[dhagin]

I used 8'-6" and 9'-6" radii to center of grout joint. Used 1/4" nominal grout joint.

Tile inside width ~ 10-7/16+
Outside width ~ 11-11/16-

looks like fun. looks like we're on the right track here.

[tilelayer]

[ob1kanobee]

I saw a tool at Home Depot where they hang the speed squares and they have this tool, I think it is a protractor or something and it comes with a computer disc that gives you the tile measurements for that which you are seeking. Keyston dimensions..............I think I'll buy the tool and return it after I copy the disc. LOL

Actually maybe not, since I think the tool was the jig as well.

[crete51]

i think give or take a.....1/16th we got it

[K_Tile]

This thread helped me out!

Grab some of this and this

Enjoy!

http://www.johnbridge.com/vbulletin/...=circle+border

[ceramictec]

that thread got me more confused. I didn't take geometry and trig in school so his hurts my head. guess I should have played less sports.

but thanks guys.

so now I need to take the difference of 11 3/4" and 10-7/16" and divide by 2
and then 11 3/4" and 11-11/16" and divide by 2 and take that off of each side top and bottom....?

[crete51]

thats already subtracted brian and we were within a 1/16 of each othr ..5/8"or 11/16" off the bottom to nothin at top both sides leaves 10 3/8 at bot 113/4 at top

[ceramictec]

ahh ok,

so the Architect probably already had a sample tile measurement and put it into his cad-cam and made the circles outside radius to fit 60 tile.
it was just up to me (us) to figure out what to take off the inside/bottom.

Thanks

[Jim wood]

I use an Anglizer. I typed in your numbers with 1/4 joint, it shows 11 3/8 top cut and 10 5/16 bottom cut, but it also says you need 68 tiles. Hope this helps.

[dhagin]

take 1/16+" off each side of outer edge
and 5/8+ off of each side of inner edge

1/8 of that circle would be 7.5 tiles. I'd probably cut 8 of any 11-3/4" tiles and lay that much out, at least.

[ceramictec]

I use an Anglizer. I typed in your numbers with 1/4 joint, it shows 11 3/8 top cut and 10 5/16 bottom cut, but it also says you need 68 tiles. Hope this helps.

he is showing 60 on the print.....now i'm lost again....lol

1/8 of that circle would be 7.5 tiles. I'd probably cut 8 of any 11-3/4" tiles and lay that much out, at least.

I'll have to mark out the inside line and outside on an open flat area, then divide it with 2 chalk lines in 1/4's and cut the 8 tile with your measurements and see how it goes.



now I need Tool Guy - KG to support these numbers with his approval and I'm straight

[dhagin]

wow Kevin, that thread was......aaaaa..........dense. I think i need an adult beverage after that

can't wait to see the finished product Brian.

[ceramictec]

thanks