We need to drill into and tap(5/8 -11) the ends of our 2.25" diameter 1018 steel shaft, it is 48 inches long. What would the best way to fixture it on the bridgeport be?
I was thinking setting the end of the shaft on the floor and bolting it to an angle plate, do we have some? What would the best way to bolt the shaft against the plate be? (I forgot to measure, but I think the quil height about 5’ from ground?)
This help?
What about a metal lathe? Is there a pass-through for it to stick out of the back of the head of the metal lathe at DMS?
I have a friend with a metal lathe that has that capability which helps when dealing with longer pieces.
The lathe only has a ~1" through bore, can’t do it without a steady rest (which I assume we don’t have), plus I don’t think the bed is long enough for the shaft plus tail stock. Otherwise a lathe would be the best tool for the job
What is the piece going to mate to, and how accurate does the location of both holes need to be. Jusging from what I have been reading about your trebuchet it is unlikely to need a tremendous degree of accuracy. In which case you don’t need a mill or even a drill press to drill a nice perpendicular hole and tap it.
I would take a small block of steel and drill several clearance holes in it (say 3/16, 5/16, 7/16, thread clearance.) The scribe and center punch the hole location. You then use the block to align the drill bits and drill with a hand drill. You can also use the block to keep the tap perpendicular as well.
The above process, with care, can produce accuracies you are unlikely to beat with jury rigged setups on the Bridgeport.
Good point, there are some holes that will matter, but these specific ones are just extra end stops to be sure the weights don’t fall off, so it just has to hold on a 3-4" diameter washer
Even when the accuracy matters, with large parts you are better off producing accurate jigs and using hand tools then trying to jury rig the Bridgeport to work with the piece in many cases.
Just be sure to use a small enough step in the drill sizes to accomodate the hand drills. If someone has an AC powered hand drill, that will certainly work better then the battery ones. If you do this with a battery drill, I expect you may need to change the battery several times, given the size of the drills you will be using.
Before you build something special, check out the Kurt Sidewinder that we have. Their promotional video alleges that you can hold something vertically off of the back of the ways/bed.
IMHO the best way to drill the hole would be to swing the Clausing around 180° and hold the shaft in a vise. Assuming you mounted the vise so as to over hang the end of your monster table. It’s much easier to do this w/ the drill press than the Bridgeport.
Also, there is a center square in the machine shop toolbox. Scribe 2 lines across the end of the stock and you have the middle.
Only if the shaft is truly round. Since most stock, epsecially of this size, is out of round it is best to draw more then two lines to narrow down the actual center if it matters.
Sure seems easier to do a hole through for a clevis pin ( a class iv trailer reciever pin should work, be cheap, readily available)…
Here there is no extra room on the end of the shaft for a pin, the concrete weights will take up basically all of the 16 inches of shaft sticking out past the upright.
Ended up drilling by hand as the bridgeport head is only about 4’ 4" off the ground, not enough height to stand bar on the floor and still fit a drillbit in.
It worked ok for this, but it is surprisingly hard to drill a perpendicular hole into solid steel by hand, here the straight edge is indicating how much of an angle I drilled at.
We might want to get a couple drill guides, aka “egg cups” with the various drill size inserts. Simple, work great, and hopefully won’t be lost in a week.
