Concete coring - weep holes in retaining wall

I am looking at renting a handheld coring drill and 4 " coring bit to drill some ( about 12 ) weep holes in a 8" poured retaining wall ( all easy access) . The wall is also face with brick where I want to to drill about 3 more holes . How long would this take with a hand held wet coring drill per hole ? .
As far at as the economics - A local concrete cutting contract wants about $5/inch of depth for a 4 inch diameter hole - t $40/hole for the unfaced portion, $60/hole for the brick faced portion . I can rent the rig for about $135 /day ( includes at Hilti handheld wet drill with a 4" X 12" coring bit w/unlimited wear included .
Can I save any substantial $ by doing the job myself and is it simple .
Recommendations and tips are appreciated . -thanks
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Did you make sure the bit is included in that price. If you have to buy a bit, that in itself makes it worth paying the pro. They cost over $100
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The bit (and unlimited wear during the rental period ) is included in the rental price.
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With a larger frame mounted wet core drill, I would budget 30 minutes per hole. Much of this time is for bolting up the frame work; the actual drilling, if the bit does not get hung up, would take 5-10 minutes, and additional time to remove the core and take down the frame. The frame functions like a drill press and allows you to keep steady controlled pressure on the bit. With the hand held in the horizontal, you will have to be the drill press. The bit needs a fair amount of pressure to maximize the cutting speed of the drill and a generous amount of water to cool and clear the bit. You will probably be wet, muddy, and tired.
The bits are expensive and a 4" bit is close to the maximum capability of a hand held drill. The core bit can get in a bind if the drill does not keep running straight. There is the potential to lose the bit and the hole if a sliver of reinforcing steel wedges the core drill in the hole. I am not trying to scare you away from the project, but rather give you as much information as possible before making your decision.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

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snipped-for-privacy@my-deja.com wrote:

4" diameter seems over kill for weep holes. Smaller holes would be a lot easier - say a 1" masonry bit & a hammer drill. I assume you have some sort of filtering medium behind the wall (i.e. landscape cloth), & gravel, which may try to ooze through. 4" holes may also be inviting to vermin.
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- rkpatt758 -

- Nehmo - If you just want weep holes on an existing wall, why bother making them 4" in diameter? Why not just get a rotary hammer and make 1" (or even less) holes?
--
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* Nehmo Sergheyev *
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