Circle Template

[Nac]

I need to make a couple templates to drill out large dia. circle in rock I will use this template to line up my rock drill to create a large hole. The hole dia. are 3'. 4', 5', 6', and 7' the drill bit dia is 5 1/8". I was thinking a 1" overlap would work. Just image a 5 1/8" hole overlapping each other to create a slot foe the 3'-7' holes. Once the first hole is drilled I can slide 5 1/8" pipe in the template and the hole to keep everything from moving.

[lotechman]

I know nothing about rock drills but the only way i could see a template would work would be if it was made from one half inch thick plate with corresponding holes burned in it 5 1/8 inch. That would be a very expensive piece of steel by the time you have it custom flame cut then tack welding pipe guides on each hole.
Can you drill a center hole then make yourself an arm that carries a short piece of pipe with a 5 1/8th inside diameter at one end and 5 1/8th OD at the other end? The one end could sit in your center hole and the short pipe on the other end locate your drill on the outside radius. You would use a lot less material since you would only need a chunk of say 4 inch square tubing for the arm each time for the radius.

[forhire]

Are you certain you are using the right tool for the job?

With a 1" over lap you'll have to drill 95 holes for a 3' hole. The diameter cut will only be 1.168" which is only 7% of your cut per hole. Your using 93% of your bore on waste. To wrap my head around this I rendered a 3' hole. See the attached image.

I don't know if you have enough material to index each hole using just the bores. You'd likely wander in a hurry.

What if you had some hoops rolled to diameter in each required size. Drill holes in the hoop and put two pins in your drill base. Then you can drill your hole, move the drill one hole and drill the next and so forth. Also, you could bolt the hoop to the rock making it more rigid. See the drawing below.

Good luck :p

[Nac]

Are you certain you are using the right tool for the job?

With a 1" over lap you'll have to drill 95 holes for a 3' hole. The diameter cut will only be 1.168" which is only 7% of your cut per hole. Your using 93% of your bore on waste. To wrap my head around this I rendered a 3' hole. See the attached image.

I don't know if you have enough material to index each hole using just the bores. You'd likely wander in a hurry.

What if you had some hoops rolled to diameter in each required size. Drill holes in the hoop and put two pins in your drill base. Then you can drill your hole, move the drill one hole and drill the next and so forth. Also, you could bolt the hoop to the rock making it more rigid. See the drawing below.

Good luck :p

Maybee my match is off but a 3' dia. circle has a circ/of 9'5 1/8" so drilling a 5 1/8" hole with a 1" overlap schouls be 28 holes. I could maybe have the template made with every other hole and then just slide the template 1 hole to drill in between. The reason I am looking to do it this way once I have a slot all the way around to remove the rest of the rock is easy with a another method. I can do this with the equipment I have insted of buying a couple 100,000.00 of new equipment.The other option is just drill a center hole and use a pice of steel as a pivot attached the my drill centralizer, slide a steel tube in the hole I just drilled and drill next to it. The steel tube is to keep the drill from walking into the existing hole.

[Nac]

Are you certain you are using the right tool for the job?

With a 1" over lap you'll have to drill 95 holes for a 3' hole. The diameter cut will only be 1.168" which is only 7% of your cut per hole. Your using 93% of your bore on waste. To wrap my head around this I rendered a 3' hole. See the attached image.

I don't know if you have enough material to index each hole using just the bores. You'd likely wander in a hurry.

What if you had some hoops rolled to diameter in each required size. Drill holes in the hoop and put two pins in your drill base. Then you can drill your hole, move the drill one hole and drill the next and so forth. Also, you could bolt the hoop to the rock making it more rigid. See the drawing below.

Good luck :p

Maybee my math is off but a 3' dia. circle has a circ. of 9' 5 1/8" so drilling a 5 1/8" hole with a 1" overlap schould be 28 holes. I could maybe have the template made with every other hole and then just slide the template 1 hole to drill in between. The reason I am looking to do it this way once I have a slot all the way around to remove the rest of the rock is easy with a another method. I can do this with the equipment I have insted of buying a couple $100,000.00 of new equipment.The other option is just drill a center hole and use a piece of steel as a pivot attached the my drill centralizer, slide a steel tube in the hole I just drilled and drill next to it. The steel tube is to keep the drill from walking into the existing hole.

[Nac]

Are you certain you are using the right tool for the job?

With a 1" over lap you'll have to drill 95 holes for a 3' hole. The diameter cut will only be 1.168" which is only 7% of your cut per hole. Your using 93% of your bore on waste. To wrap my head around this I rendered a 3' hole. See the attached image.

I don't know if you have enough material to index each hole using just the bores. You'd likely wander in a hurry.

What if you had some hoops rolled to diameter in each required size. Drill holes in the hoop and put two pins in your drill base. Then you can drill your hole, move the drill one hole and drill the next and so forth. Also, you could bolt the hoop to the rock making it more rigid. See the drawing below.

Good luck :p

Maybe my math is off but a 3' dia. circle has a circ. of 9' 5 1/8" so drilling a 5 1/8" hole with a 1" overlap schould be 28 holes. I could maybe have the template made with every other hole and then just slide the template 1 hole to drill in between. The reason I am looking to do it this way once I have a slot all the way around to remove the rest of the rock is easy with a another method. I can do this with the equipment I have insted of buying a couple $100,000.00 of new equipment.The other option is just drill a center hole and use a piece of steel as a pivot attached the my drill centralizer, slide a steel tube in the hole I just drilled and drill next to it. The steel tube is to keep the drill from walking into the existing hole.

[forhire]

Maybe my math is off but a 3' dia. circle has a circ. of 9' 5 1/8" so drilling a 5 1/8" hole with a 1" overlap schould be 28 holes. I could maybe have the template made with every other hole and then just slide the template 1 hole to drill in between. The reason I am looking to do it this way once I have a slot all the way around to remove the rest of the rock is easy with a another method. I can do this with the equipment I have insted of buying a couple $100,000.00 of new equipment.The other option is just drill a center hole and use a piece of steel as a pivot attached the my drill centralizer, slide a steel tube in the hole I just drilled and drill next to it. The steel tube is to keep the drill from walking into the existing hole.

My mistake. I figured each bore would move forward by 1". Your math makes a lot more sense :rolleyes:

New drawing with only 28 holes and a possible guide idea.

[Nac]

Yes that 2nd drawing of the guide looks like it would work. I wounder if you can change it to only 3/4" overlap and only a 4 3/4" hole. And the center positioning hole would also be 4 3/4". Would just have to make one for a 3', 4', 5', 6', and 7'.

[Nac]

Or maybe it can be made that the center roud is pined on to boyj ends and I can have difrent center rod lengths

[forhire]

Yes that 2nd drawing of the guide looks like it would work. I wounder if you can change it to only 3/4" overlap and only a 4 3/4" hole. And the center positioning hole would also be 4 3/4". Would just have to make one for a 3', 4', 5', 6', and 7'.


As drawn you'd need one for each size because the pipe index to the last hole and it's relationship to the new one is on a radius which would be different at different diameters.

Or maybe it can be made that the center round is pined on to both ends and I can have different center rod lengths

This would be ideal but requires a different design as noted above. I'll see what I can come up with.

[forhire]

Behold the bore-tractor :laugh:

I think this is a long the lines of what lotechman described.

Consists of a 42" arm with various 0.5" holes. Each 0.5" hole has a 0.25" index hole, these align the arm to the appropriate index hole on the 12" index plate. The 3' hole has 28 holes, 4' has 38 holes, 5' has 48 and so forth. the 7' hole uses 68 holes. This assumes 4.75" core drill with a 1" overlap. Might be able to get by with one or two less holes per circle which might save time and core drill life.

With little effort you could include an 8' circle by making the arm 4' long and adding one more row to the index. No need to telescope unless you don't have the space for the tail to rotate around.