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3rd December 2014, 10:09 AM #46Try not to be late, but never be early.
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I'm making the cranks out of 12mm mild steel bar. There are six of them so I made a jig to get them roughly the same. To true them I put one end in the chuck of the pedestal drill and at slowest speed chalk the high spot. I have found that the end in the chuck is the one to adjust to remove the run out at the other end.
Geoff.
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3rd December 2014 10:09 AM # ADSGoogle Adsense Advertisement
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30th December 2014, 10:47 AM #47Try not to be late, but never be early.
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I've made a mock up of the machine. With the two feed shafts that Michael made and the two connecting shafts and six bosses to hold the augers made by a friend down at Harvey. Still lacking the drive gears but I've connected a brace to the end of the second crank temporarily. The original machine has five cranks with provision for a sixth and evidence of wear to show that a sixth bit was there at some time, so I've set this one up with six cranks.
Over the Christmas period I've had a few visitors give their opinions and one is that the machine was possibly mounted vertically boring downwards into the post.
For the mock up I have fitted three 1/2" bits with a sleeve in the boss to take up the slack between the shank of the bit and the ID of the boss. The original probably had 1/2" augers with their eye removed as the shank of a couple I've got are the approximate diameter (3/8") as the hole in the boss.
Every time I walk past it I can't resist giving the crank a few turns, the action of the connecting rods is mesmerising, (simple things amuse etc.)
The difficult part next is to determine how the feed engagement mechanism was made. Being a fairly unsophisticated tool I'll have to ensure that whatever the solution it has to be fairly simple.
As previously discussed Michaels feed screws are dual purpose. If we accept that the machine was mounted vertically, the coarse LH thread with pin drive engaged and crank turned backwards lowers the auger bits to engage the post. At this point the pin drive is disengaged and the 3/4" UNC half nut drive is engaged and turning the handle in the correct direction helps drive the auger bits through the post. Once the post is drilled the UNC is disengaged and the pin drive reengaged and still turning the crank in the correct direction the bits are raised from the post ready for another one.
Clear as mud? Well I understand how it's going to work, the trick will be to make this part of it compatible with the style of the rest of it. Folks, I'm still on the lookout for the two cogs 26 and 10 teeth, I've had some offers of machining them or casting them and will look at those options if I'm unable to locate them at a clearing sale or the like, over the next few months.
Cheers,
Geoff.
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30th June 2015, 10:11 AM #48Try not to be late, but never be early.
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Update.
A couple of days ago Michael G asked me how I was getting on with this project. Well not a lot has happened since December. I've made a pair of thread followers that would allow the machine to move forward and backward (up and down) and have also found a pair of cogs of the correct tooth number. The followers were made by drilling and tapping a 3/4 UNC hole in a piece of steel. A second 3/4 hole was bored adjacent to the first and the land between the two holes cut out with a hack saw. Then it was careful use of a file to where the threaded rod, when inserted, could be moved from engaging the threaded section accross to the smooth section. Next step was to drill and tap a hole in the end of the steel block to accept a 1/4 screw with the end filed down to engage in the coarse thread in the rod.
The two blocks are attached to a carriage that allows me to demonstrate the principle of how I think the machine was used. If it was operated vertically I imagine that it would have been counterweighted to neutralise the weight of the contraption on the raising /lowering mechanism. Whether the drilling heads were raised and lowered to engage a post in a static carrier or the machine immovable and the post carriage raised and lowered, I'm not sure, but I'm leaning towards the former. Varying weights of the posts being bored would make it impossible to effectively counterweight the post carrier.
The three photos sort of illustrate the above.
Cheers,
Geoff.
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30th June 2015, 06:02 PM #49Senior Member
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Looks good Geoff. Original solution to engaging the different threads, I like it.
Do you know what machine the gears came from?
I put the word out around here and also checked out every old machine and junk pile that the owners would let me have access to and came up with nothing.
I would be interested to know how well it works when it is finished.Regards
Bradford
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1st July 2015, 09:03 AM #50Try not to be late, but never be early.
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Hi Bradford,
I picked up the two gears from a farmer between Toodyay and Bindoon, he had boxes of them in his shed, not exactly the same but right number of teeth. In discussion with my wife's cousin at Busselton last week he's sure the originals are off a hand winch.
Since I saw you I've been to a number of clearing sales and turned up a blank as well.
Cheers,
Geoff.
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