Making holes in fence posts for the rails, looking for ideas

[plasticweld]

I was wondering if anyone has come up with a gasoline powered drill large enough to drill a three inch hole "top and bottom" in a locust post, that can be then be connected by a chain saw cut to make the opening for the rail.  I have been doing it with a carving chainsaw cut? I figured there must be a better, faster and safer way to do a lot of posts.  Doing a google search has yielded little. Figured I would ask here I can't be the only one trying to crack this nut...Thanks in advance

[GAB]

In reply to your question I offer the following:
There are drilling attachments made that mount to a chainsaw.  I've seen some in catalogs for tapping maple trees.  Would it be possible to use one of those with a Forstner bit of the right diameter and then finish the rail opening with a chainsaw?
That is my thought on the subject.
GAB

[longtime lurker]

There's a couple on manufacturers that make gas powered drills for that kind of thing, probably the best of them I ever used was a Tanaka in terms of reliability and getting the job done.

Google Atom Borer to get a look at the chainsaw attachment type, they're good but not as good as the engine driven drills. The chainsaw head type relies on you pulling backwards to engage reverse gear, and that can be difficult when the drill is pulling itself forward.

For just a few holes why not use a genset, and an electric drill?

3" is going to be tough whatever way you do it.  Take along a monkey wrench for winding bits back out when they bog down in the post.

[drobertson]

If you are talking about a production run for such as a business, there are ways to do it.  It will cost, but possible,  I worked for a timber outfit for a year sawing timbers that they ran down a line to be bored with close tolerance hole spacing and diameters.  Now these holes were not 3" dia. and the bits were costly, but lasted quite awhile.  They ran on electric motors with limit switches that triggered the drive when the cants were in position.  Pretty sure 3" dia. cutters will set you back, but if the end product works then there is potential.

[plasticweld]

If you are talking about a production run for such as a business, there are ways to do it.  It will cost, but possible,  I worked for a timber outfit for a year sawing timbers that they ran down a line to be bored with close tolerance hole spacing and diameters.  Now these holes were not 3" dia. and the bits were costly, but lasted quite awhile.  They ran on electric motors with limit switches that triggered the drive when the cants were in position.  Pretty sure 3" dia. cutters will set you back, but if the end product works then there is potential.

It is for business and for doing hundreds of posts, do you think there would be anyway to use a gas powered motor instead of electricity.  I don't have more than 220 volts where the saw mill is.  All of the big milling machines I looked at too 440

[tmarch]

A 3 inch forstner bit in drill press would be my first thought.  Could be ran off 120 or 240 depending on the motor.  A table with stops for making the holes at even spacing could be added easily and all the holes would be the same depth from the middle of the post by setting the stop.  I've done a few on a Shopsmith.

[Larry]

The only reason 440V and higher are used is to reduce cost.  230 volt should be fine for your application.

I second the idea of a drill press.  How deep does the hole need to be?  About the deepest most drill presses will go is 6" and that is with old USA iron.

Actually this may be a situation where a custom machine makes sense.  Poston40 make a drilling machine for a tenon cutter.  Do a search and you can find it.  Little modification of the design....

[Don_Papenburg]

Bridgeport ...........  Use a roughing cutter and it will put in the slot with rounded ends

Out in the field use the Milwaukee 18v battery drill  with the big battery  to drill the holes for the chain saw.

[MattJ]

I would think for hundreds of locust posts you will go through a lot of forstner bits.  That will be a slow go as well even with a drill press.  I bought a chain mortising attachment for a radial arm saw that works pretty quick from woodworker supply and then hooked it up to a $100 1970's radial arm saw from craigslist.

There are timber framing plunge chain mortisers that are portable and run off 110 that would knock square holes out all day long pretty accurately.  They are pricey though, probably near $1000 even used, and leave a square or rectangle hole.  Not sure if that would be OK.  I've used one in pine and a scrap oak piece in Jim Rodgers timber framing class and it would knock out a hole in seconds.   They also have indexing fences to ensure the hole is always in the same spot post to post.

[LittleJohn]

How about a 3" self feeding drill bit??

Just get ready to hang onto that drill  ;D I have a 1.5" and you have to hang on to that one with all your might

[Kbeitz]

I would set up a jig with a 3-4 hp briggs engine useing a mill hog to cut your hole.



 

[terrifictimbersllc]

How about a 3" self feeding drill bit??

Just get ready to hang onto that drill  ;D I have a 1.5" and you have to hang on to that one with all your might

If he's using a drill capable of 3" boring, and the bit stops turning, then he'll be turning.  Or his wrists will be and his body won't!  Or the work piece will be.

[North River Energy]

This drill will run off a small generator/110v.
Reduction drive, 3/4 chuck, (1/2" ratchet for scale).


 


 
Enough torque to be really dangerous.
I think it came from boatyard/navy surplus?


If this is an ongoing job, I'd look into something driven by a hydraulic motor, using an annular cutter.
http://www.hougen.com/cutters/heavy-duty-industrial-annular-cutters/hdindustrial-annular-cutters.html
Assuming the spindle assembly is rigid enough, you could cut the slot in steps by advancing the post rather than connecting two holes with saw cuts.
Or drill two holes, then connect using ganged electric chainsaws for one plunge cut.

If there are any surplus machinery dealers in your area, you might be able to find an old radial drill or milling machine to use as a base for this thing.
Also keep an eye on Craigslist for obsolete drilling machinery.

End design really depends on how fast each post need to be slotted, and how much time/money you want to dedicate toward a solution.

[drobertson]

You know Kbeitz has a pretty good idea, I'm not sure of the rpm's a little Honda or Briggs runs, but fixing up an adaptor on the engine shaft and tool holder,  maybe even have a jig that the engine can set in to secure while plunging, I see all kinds of options,  If gas has to work for now. Those cutters are a bit pricy but so is everything else these days, and can be re-sharpened by most tooling shops that provide the service.

[just_sawing]

The predrilled post sold in different places come out of MT and ID. Does anyone have video on how they do it?

[LittleJohn]

How about a roughing end mill??

[Grandedog]

     Howdy,
   I don't know if will help but, I did some round rails going into a round post by using a hole-saw. In the post, you can bottom it out and then knock the plug out to go deeper if needs be. In the rail, drill into the center (from the end of course) until it bottoms out. Then working from the outside of the rail, use a saw to crosscut the rail to intersect the bottom of the hole-saw cut.
   I know this wouldn't be very fast for a production situation but, it might give you some ideas.
   You didn't mention how wide of a groove you needed to make. There's a Groove Cutter made by Makita, it's a a model 3803A. They were discontinued a while ago but, if you can find one, they're fast. There's also a chainsaw attachment for cutting grooves, it's called a Log Master.
Regards
Gregg

[Ox]

How about using a chainsaw?  Two vertical cuts, then two diagonal cuts, then float/feather to clean up the ends.

[LAZERDAN]

Make something like this. Just a thought.

woodgears.ca/pantorouter/large_mortise

Even if you don't use it it's cool

                                                           
Pre-built all-metal pantorouter
OK I give up! Just copy and paste this it's cool            Lazerdan

[LittleJohn]

How about a jig and plunge router??  I have a feeling it could be set up fairly quickly and accurately