[HELP] Concentric Turning To A Bore

[EdK]

(04-16-2014, 10:12 PM)TomG Wrote: Ed,

I would face the stock to length and drill and ream the 17mm hole. Then I would chuck a piece of stock and turn a stub arbor with a shoulder with a snug fit in the the reamed hole. Then you can slip the part on the stub arbor, center drill the opposite end and support it with a center to finish the O.D. This way there is no indicating to be done and the I.D. and O.D. will be perfectly concentric.

Tom

This is exactly the way I envisioned doing it, to the letter. I just wanted to make sure I wasn't over engineering the process so I thought I'd get some ideas from you guys.

Ed

[EdK]

(04-17-2014, 06:37 AM)TomG Wrote: I use that technique quite a lot Ken and it works well. You are correct though, it does require a close fit on the bore, which is pretty easy with the reamed part as a gauge. I would personally bore and turn that end in the same set-up and then flip and indicate for the other end, but Ed stated that he wanted to use a reamer it so making a stub arbor or pressing a mandrel in the bore would be the best option.

Tom

I don't necessarily want to use a reamer. I was just voicing my opinion on how I thought I should do it. Plus, I have a 17mm reamer already. If boring is a better way to go then I don't have anything against boring instead of reaming.

Thanks for all of the ideas guys.

Ed

[EdK]

(04-17-2014, 06:37 AM)TomG Wrote: ...I would personally bore and turn that end in the same set-up and then flip and indicate for the other end, ....

Tom

This is the method I'm leaning towards. Oh, and by the way, I do have a 4-jaw chuck.

Ed

[TomG]

Oops! Looks like Greg beat me to it.

[henryarnold]

Ed,

I did the same adapter for my mill. I turned and threaded the outside diameters and then used a boring bar to do a very close tolerance inside bore. I also added two set screws to the shaft and slot for the gear.

   
[attachment=8157]
   
   
   
   

[EdK]

Thanks Henry. It's your version that I'm copying. I bought the power feed long ago and did the drawings based on your design long ago also. I really want to get this done since it would be so handy. Do you find the set screws are holding just fine? I was thinking of using a roll pin to pin the adapter to the leadscrew.

Ed

[henryarnold]

(04-18-2014, 03:55 PM)EdK Wrote: Thanks Henry. It's your version that I'm copying. I bought the power feed long ago and did the drawings based on your design long ago also. I really want to get this done since it would be so handy. Do you find the set screws are holding just fine? I was thinking of using a roll pin to pin the adapter to the leadscrew.

Ed

Ed,
My installation has been in use for two years and I have had no problems. I was able to get a very close fit on the bore which is important. The set screws hold fine. I didn't consider any other method of holding the adapter in place. My original handle had a roll pin through the shaft but in typical off shore fashion it ws drilled off center and crooked. I would have been tough to put a hole in my adapter to match the crooked feed screw hole.

I must confess, I started three adapters and messed up the first two before I got one that was good. When I was threading the third adapter, I was very nervous because it would have been easy to mess up yet another one and loose hours of work. I should also mention that I had to fiddle with the spacing of the gear using the assortment of shim washers supplied with the power feed. I use the power feed ALL the time and it makes a much better fly cutter finish than I can do by hand cranking.

Have fun mounting your power feed. You'll love it once you you get it going.
Henry Arnold

[henryarnold]

Ed,

One other thing that is important. Your large dameter length of 3.250 is fairly critical once you mount the adpater to your lead screw because it sets the mesh of the pinon gear to the ring gear. To a point you can move the ring gear out using the supplied shims but it should be close. I had to remove my adpater and take just a small amount off the face of the large diameter to move the ring gear in just a bit. I ended up only needing a small amount of shim.

Henry

[EdK]

(04-18-2014, 04:20 PM)henryarnold Wrote: Ed,

One other thing that is important. Your large dameter length of 3.250 is fairly critical once you mount the adpater to your lead screw because it sets the mesh of the pinon gear to the ring gear. To a point you can move the ring gear out using the supplied shims but it should be close. I had to remove my adpater and take just a small amount off the face of the large diameter to move the ring gear in just a bit. I ended up only needing a small amount of shim.

Henry

Yup, I realized that yesterday while I was staring at the drawings so I got the power feed out and took some measurements and had to change some dimensions on my drawings.

I need to fix my cross slide movement problem before I tackle this project though.

Ed