- Joined
- Feb 8, 2014
- Messages
- 11,177
OK.... On with the show.
So the final part of the first drill fixture is the end stop, so grab a chunk of aluminum and chew it out. I would have done this in the vice except the next operation needs just the table again, so I grabbed another piece of MDF that had been used for some other parts and just screwed this piece down. Nothing too special, 3x1.5x0.25'' aluminum.
First manually slice off the excess
Then profile and machine the step, and done.
Then on to the next fixture. This one is to drill another couple of parts.
2 pieces of 3/4 MDF screwed together 6.25x22.5''
Drill bushings come in from both the sides and the top. With the exception of the double bushing plate, the drill bushings will be 1/4-20x3/4 set screws with a 1/8'' hole drilled through. These will be threaded into the tapped holes in the MDF. The double bushing (on the left) is a chunk of 4150 because that's the closest thing I had to tool steel on the shelf.
I had a piece of coated particle board in my stack of stuff that was just the right size for this part, and it was already drilled and C-sunk to mount on the table.
Then I screwed down the piece of 10x24 MDF to the particle board, then drilled the pilot holes for the top piece. These are over width because I have a number of pieces of MDF cut into 10x48 pieces just to fit my mill table.
0,0 is at the top right corner of the finished part, not the raw material, and will remain there for the of this job. I located this point on the particle board and made sure that the raw material covered that so there material to remove to finish. The nice thing about having the raw material oversize and them machining all sides is that location is not critical, you only need to make sure that you are going to remove material all around.
Then overlaid the top piece and ran the drill pattern again, and screwed the top piece down. Now I'm ready to make sawdust.
This time I'm actually using a router bit for it's intended purpose.
So chew off the outside to size.........
(I'm still amazed at the fast shutter with the flash on my cheap little point and shoot camera, that spindle is turning about 3200 RPM, no motion blur at all)
And then cut out the inside. Again actually using a router bit, 1/4'' this time. Now the inside and outside profiles are finished, time to drill & tap for the drill bushings.
So now need to put the holes in the sides, so I'll get out my 90 degree angle drill bits and ........ Oh, wait a minute
Now I have a problem. The truth is at this point in the job I was still deciding on how I was going to put the side holes in. I actually stopped here for the night and decided to sleep on it.
So I came up with a plan, put another screw in at roughly the point of the scribe.
Then make a saw cut to separate the sides. Now I have two removable pieces that are easy to work with.
Then while I still had the base screwed down, I pocketed the double drill bushing pocket.
When I profiled the outside with the 1/2'' router bit, I purposely went a bit deep to get a clean edge and it left a very nice 1/2'' channel, this worked out well for the next operation.
Grab some 1/2'' square lathe tool bits, pop them in the channel as backstops, and instant part location, same 0,0 as the rest of the job. Hold down with a couple of screws and washers, along with a piece of scrap and instant fixture.
And done, drilled & tapped, did the same with the end piece.
So the last piece is the double drill bushing. This one is going to require the vice back on the table.
As I said earlier, the closest thing I had to tool steel is some 3/4 thick 4150. The drill bushing is 0.250'' thick so going to need to remove about 2/3 of the raw thickness.
That will be a job for tomorrow.
So the final part of the first drill fixture is the end stop, so grab a chunk of aluminum and chew it out. I would have done this in the vice except the next operation needs just the table again, so I grabbed another piece of MDF that had been used for some other parts and just screwed this piece down. Nothing too special, 3x1.5x0.25'' aluminum.
First manually slice off the excess
Then profile and machine the step, and done.
Then on to the next fixture. This one is to drill another couple of parts.
2 pieces of 3/4 MDF screwed together 6.25x22.5''
Drill bushings come in from both the sides and the top. With the exception of the double bushing plate, the drill bushings will be 1/4-20x3/4 set screws with a 1/8'' hole drilled through. These will be threaded into the tapped holes in the MDF. The double bushing (on the left) is a chunk of 4150 because that's the closest thing I had to tool steel on the shelf.
I had a piece of coated particle board in my stack of stuff that was just the right size for this part, and it was already drilled and C-sunk to mount on the table.
Then I screwed down the piece of 10x24 MDF to the particle board, then drilled the pilot holes for the top piece. These are over width because I have a number of pieces of MDF cut into 10x48 pieces just to fit my mill table.
0,0 is at the top right corner of the finished part, not the raw material, and will remain there for the of this job. I located this point on the particle board and made sure that the raw material covered that so there material to remove to finish. The nice thing about having the raw material oversize and them machining all sides is that location is not critical, you only need to make sure that you are going to remove material all around.
Then overlaid the top piece and ran the drill pattern again, and screwed the top piece down. Now I'm ready to make sawdust.
This time I'm actually using a router bit for it's intended purpose.
So chew off the outside to size.........
(I'm still amazed at the fast shutter with the flash on my cheap little point and shoot camera, that spindle is turning about 3200 RPM, no motion blur at all)
And then cut out the inside. Again actually using a router bit, 1/4'' this time. Now the inside and outside profiles are finished, time to drill & tap for the drill bushings.
So now need to put the holes in the sides, so I'll get out my 90 degree angle drill bits and ........ Oh, wait a minute
Now I have a problem. The truth is at this point in the job I was still deciding on how I was going to put the side holes in. I actually stopped here for the night and decided to sleep on it.So I came up with a plan, put another screw in at roughly the point of the scribe.
Then make a saw cut to separate the sides. Now I have two removable pieces that are easy to work with.
Then while I still had the base screwed down, I pocketed the double drill bushing pocket.
When I profiled the outside with the 1/2'' router bit, I purposely went a bit deep to get a clean edge and it left a very nice 1/2'' channel, this worked out well for the next operation.
Grab some 1/2'' square lathe tool bits, pop them in the channel as backstops, and instant part location, same 0,0 as the rest of the job. Hold down with a couple of screws and washers, along with a piece of scrap and instant fixture.
And done, drilled & tapped, did the same with the end piece.
So the last piece is the double drill bushing. This one is going to require the vice back on the table.
As I said earlier, the closest thing I had to tool steel is some 3/4 thick 4150. The drill bushing is 0.250'' thick so going to need to remove about 2/3 of the raw thickness.
That will be a job for tomorrow.
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I was able to drill about 5/8 deep reliably, but that last 1/8 inch proved to be a PITA, I suspect that the screw was harder at the end than through the rest of the body. 4 screws and 4 drill bits later I gave up and went with some softer screws.
Now back to my rotary parts counter project.
