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[4]

Shop Made Axa Toolpost Cross Drilling Fixture

January Project of the Month [3]
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JPMacG

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#31
Thanks Mike. I need one of these myself!

Are the bearings pressed onto the shaft? Or is the shaft a slip fit into the bearing inner races and you drill by pushing on the drill?
 

Ulma Doctor

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#32
Thanks Mike. I need one of these myself!
Are the bearings pressed onto the shaft? Or is the shaft a slip fit into the bearing inner races and you drill by pushing on the drill?
Hi JPMacG,
Yes Sir, the bearings are a light press fit- .001" interference to the shaft
i froze the shaft and slightly warmed the bearings with a heat gun- approx 100*F and pushed them together by hand
after temperature equalization the bearings are effectively, press fit.
the clamp bushing is responsible for holding the assembly for use
 

JPMacG

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#34
For the toolpost fixture I found a little 1/4 inch capacity chuck in my collection of junk. It looks to be high quality and has no sign of damage. It mounts with a 3/8-24 thread. It is branded "Chicago" and is US made.

I cut a 3/8-24 thread on the end of a piece of 3/8" round stock and, with the stock still on my lathe, I mounted the chuck. I was surprised to find that the chuck wobbles badly. So I cut another thread, this time making it a snug fit to the threads of the chuck. It still wobbles badly.

So my question is, how are these types of chucks kept true? I see photos that show chuck mandrels with a flat below the threaded stud and it appears that the chuck is supposed to seat against the flat. Should I use larger stock and provide a similar flat on my part?
 

Randall Marx

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#35
Yes, Jon, I would think one should have a threaded shank with a shoulder for the chuck to seat against. Also, see if there is a recess in the chuck that would go over an unthreaded portion of the mounting shank, that could seat on a register between the threads and the shoulder. I'm thinking of something like the register on a threaded lathe spindle nose.
Another thought is this: does the chuck body wobble or is it a test bar (like a dowel pin) that wobbles when chucked? Might pay to check with a dowel pin or drill bit if you haven't yet. If a drill bit runs true but the chuck body wobbles, I wouldn't worry about it.
Either way, please let us know what you come up with.
-Randall
 

JPMacG

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#36
Thanks Randall. Yes, that was it. I made another part out of 5/8" round stock with a flat for the chuck to seat on. The flat made a huge difference. The wobble is gone.
 

JPMacG

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#38
Had a chance to finish my cross-drilling fixture last weekend. It works well. I used it to make a replacement part - a shaft with through holes oriented at 90 degrees - for the powered feed on my mill. I have a bit of runout on the drive side of the fixture, so the drill vibrates a bit. But the chuck runs true.

Cross-Drill-Fixture.JPG
 

benmychree

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#40
That's a cool project, Mike. I can think of a couple instances where I could use such a tool.

Did you use the back gears to lock the spindle or do you have a slick indexer for the spindle?
There is a dividing head that mounts into the back end of a lathe spindle, made by Master Mill, I think It has a expanding bushing to grip the ID of the spindle and a torque arm to hold the body stationary; I have one, but never have used it; It would be used in conjunction with their powered milling attachment. I was fortunate to be asked to participate in a estate sale, to price some of the machine related items; the place was a real treasure trove, the man had been a college machine shop teacher and in that capacity was able to "survey" surplus for the school; as it turned out, it was whatever quantity for the school and at least two for him; in his SDA community, most of the prospective buyers were a pretty thrifty lot, so much left over that we got for very cheap, including most of the Master lathe milling setup, and I also found missing items on e bay, so have nearly all of it. Now, if I could just figure out a job to do with it!
 

middle.road

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#41
Cross Drilling Fixture from an AXA Boring Tool Holder!
i had an idea to make a cross drilling fixture for my shenwai 1236 lathes' AXA clone toolpost.
an old 19.2 craftsman drill is powering the works.:grin:
estimated total project cost= under $5 (i had everything on hand and had to assign a nominal cost:cool 2:)
thanks for looking!
(/me dusting off thread) Just saw this, I hope you made several of these to give out as gifts next Christmas, since I didn't find one in my stocking this Christmas. :grin:
Here's mine. A Foredom type hand piece driven by a flexshaft going back to a 3600RPM old KitchenAid dishwasher motor.
(Can't find a pict of the motor...) Rube Goldberg has got nuthin' on me!
I wonder if I can re-do this into the holder style you used...
1516411705168.png
Grinder mode, before I got the Dumore. Actually worked out for finish grinding the ends of 1/2" Dia. rods to size. (NOT with that wheel...)
1516411828616.png
 

Ulma Doctor

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#42
(/me dusting off thread) Just saw this, I hope you made several of these to give out as gifts next Christmas, since I didn't find one in my stocking this Christmas. :grin:
Here's mine. A Foredom type hand piece driven by a flexshaft going back to a 3600RPM old KitchenAid dishwasher motor.
(Can't find a pict of the motor...) Rube Goldberg has got nuthin' on me!
I wonder if I can re-do this into the holder style you used...
Grinder mode, before I got the Dumore. Actually worked out for finish grinding the ends of 1/2" Dia. rods to size. (NOT with that wheel...)
Thanks for looking!
i didn't think to make extras, but i should! :grin:
nice work!
i should steal your idea :)
 

Tozguy

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#43
Great ideas folks. Could anyone give me the bearing numbers?
My BXA sized boring bar holder is for 3/4'' bars. The i.d. of your bearings seems to be 3/8''. Is that the largest I.D. available?
Thanks for your help.
 

Ulma Doctor

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#44
Great ideas folks. Could anyone give me the bearing numbers?
My BXA sized boring bar holder is for 3/4'' bars. The i.d. of your bearings seems to be 3/8''. Is that the largest I.D. available?
Thanks for your help.
Hi Tozguy,

I used R4 bearings 5/8" OD x 1/4" ID x .196" thick

you may be able to use R4a bearings their dimensions are 3/4" OD X 1/4" ID X .281" wide

you may be able to work with a 6800 metric bearing 19mm OD X 10mm ID X 5mm wide (but the OD will be slightly smaller than 3/4")
 

mattthemuppet2

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#47
these are surprisingly useful. I made one ages back as more of a practice in making dovetails and I've used it far more than I would have expected. My lathe (Atlas 618) also has an indexer built into the bull gear, so I can use the lathe like a dividing head (sort of) for doing bolt circles :)
 

Tozguy

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#48
You are very welcome!
i'd like to see your version ! :grin:
Could not find any ball bearings of the size I wanted (minimum 3/8ths. shaft). so had a look at needle bearings. Then realized that bushings should work. So went that route, cost of $4 for two .75/.50 x .75 porous bushings.

Had great enjoyment from getting things concentric with minimum clearances. Realized that the bushings are 'compressible' ie. the bushing/shaft clearance can be reduced by torquing the two clamp screws in the BXA holder.
 

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Last edited:

fixit

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#49
Cross Drilling Fixture from an AXA Boring Tool Holder!
i had an idea to make a cross drilling fixture for my shenwai 1236 lathes' AXA clone toolpost.
View attachment 187318


i machined the shaft from 3/8" 12L14 hex shaft and single point threaded the drill chuck end to 3/8-24 to accept an old but new Jacobs short 1/4" capacity chuck.

View attachment 187320
i left just enough of the hex so that i can put a 3/8" wrench on the spindle to remove the drillchuck
the shaft is supported by 2 mini bearings, one inboard, one out board.

View attachment 187324

View attachment 187331
the clamping action of the sleeve in the boring bar holder is sufficient to keep the shaft in place during the cross drilling operations.


View attachment 187333

View attachment 187334

View attachment 187335

an old 19.2 craftsman drill is powering the works.:grin:
estimated total project cost= under $5 (i had everything on hand and had to assign a nominal cost:cool 2:)
thanks for looking!

You should patient that
 

mattthemuppet2

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#50
Could not find any ball bearings of the size I wanted (minimum 3/8ths. shaft). so had a look at needle bearings. Then realized that bushings should work. So went that route, cost of $4 for two .75/.50 x .75 porous bushings.

Had great enjoyment from getting things concentric with minimum clearances. Realized that the bushings are 'compressible' ie. the bushing/shaft clearance can be reduced by torquing the two cinch screws in the BXA holder.
that's what I did too, works fine for me. I added a small oiling port in the holder I made, sealed with a set screw, to add some oil every now and then.
 
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