# BP Power Feed Shaft Project w/?



## Kroll (Mar 9, 2020)

Guys I have hit snag on installing my PF for the X axis.My mill had the 8F PF that I guess gave up ghost sometimes back. Anyway removing it I now see that I need an extension shaft so that PF will work. Well I guess this would be a good project for me since just turning an OD is still a big challenge,but I also wish I had an ideal of the length that I need to make it. So this project is a guessing game that I am going to break down into sections so that I don't get loss. My first project for this shaft is just turn OD down to 13/16 or .812 Now simple right, well not for me. On some of my other projects it seems that I always over shoot and miss,so this time going to take it easy which I rough it down to size with carbide insert. Then using Doc's HSS tool that he sent me roughing on one end and finish on another.  I rough it down little more now I'm getting closer to the finish so switching to the finish end of the cutter and so far so good. Going to take it down just another thou and that should be it for the 13/16 which I will check with the coupling that connects lead screw to the extension shaft. Going to make shaft longer than what is needed since having to guess at length,but its trial & error which I hope no error


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## DavidR8 (Mar 9, 2020)

Are you supporting that with the tailstock?


Sent from my iPhone using Tapatalk


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## zamboni2354 (Mar 9, 2020)

DavidR8 said:


> Are you supporting that with the tailstock?
> 
> 
> Sent from my iPhone using Tapatalk


My thought when i saw the pic as well


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## markba633csi (Mar 9, 2020)

Yes skinny pieces longer than about 3" should be supported by a tailstock center, especially if your lathe is a bit worn and cuts taper

-mark


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## projectnut (Mar 9, 2020)

Before going any further I would strongly suggest relocating the shaft in the chuck.  Rule of thumb is a work piece can be extended no more than 5 times the diameter beyond the chuck before you'll get taper due to deflection.  First relocate it so less than 5X the diameter is sticking out.  Then  using a 60* center drill make a pocket in the end just large enough to accommodate a center.

Once the pocket is created you can extend the shaft with one end in the chuck and the other supported by a live center in the tailstock.  Now you have a sturdy fixture and the shaft won't deflect as you push against it with the tool.

As for the finished diameter I would first either create or purchase a coupling.  I made a coupling out of 1 1/2" diameter 6061 aluminum round stock. I cut off a 2" length then bored it ( actually drilled it) to .812".  I then put it in the mill and drilled and tapped 2, 5/16-18 holes for set screws.  The final step was to broach a 1/8" keyway under the set screw holes.  I knew a new coupler would be necessary when I took apart the assembly.  I'm not sure who made it, but it was a modified version of a Ruland 3/4" 2 piece coupling.   When the hole was rebored it was about .025" off center.  This caused the new shaft to wobble in the power feed bearing housing

As an FYI the original Ruland coupling would have needed to be modified again to work with the power feed.  It was 2 1/4" long, and even pushed back as far as possible on the lead screw it would still rub on the new mounting plate for the power freed.  Rather than attempt to resurrect that coupling given all it's problems, it was easier to just make a new one. 

Once you create or purchase a new coupling you can decide how much more if any needs to be removed from the shaft for it to fit into the coupling.

In my case I already had a shaft that worked for the manual setup.  It was a bit shorter than would have been optimal for the power feed, but I was able to reuse it.  It no longer butts up to the leadscrew in the coupling, and is a couple threads short of the nut fully engaging on the handle, but it does work.  My current plan is to use it as is until I'm satisfied with the performance of the power feed.  Once that's accomplished I'll remove the power feed, measure the existing shaft and determine how much longer the new one should be.  I'm thinking the optimal size will be only about 1`/2" longer than the existing one.

I probably should have measured the existing shaft when I had it out, but at that time I wasn't sure whether or not a new one would be necessary.  Leaving your shaft a little over length is a good plan at this time.  Once you get everything in place you can make a final measurement, cut and then thread the shaft.


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## Kroll (Mar 9, 2020)

Thanks guys I move the live center out of the way for pic, But as careful as I was when I was turning OD for the bushing that goes into the roller bearing I took off to much.That was my last piece so going to order myself some 7/8 1144, dang my bad luck. But this project is on hold for now so going to read all post and take all the advice make notes to keep by my lathe just as a reminder. Thanks Projectnut for the #'s and the details cause you and I have the same problem and same mill I believe. So going to read details and come up with a plan and make myself a drawing to look at instead of me guessing thinking I'm safe making a cut.


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## talvare (Mar 9, 2020)

You've said that you're having trouble with getting to your final dimension with out over-shooting and turning the part under size. I would suggest that when you make a cut that is within .001-.002 of your desired final dimension that you make a spring pass. That is make another cut without moving the cutting tool. You will generally find that it will cut another thousandth or so without changing the DOC. Sometimes, depending on the amount of flex you're getting in the part, it will continue to cut on two or three spring passes.
Just some food for thought.

Ted


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## Kroll (Mar 9, 2020)

Good news guys I am back in business.Had to dig little more but found 1" 1144,just have to turn OD little more but I do need the practice.Thanks Ted for passing that info about spring pass.That is something that I need to do so that I can keep from over shooting.Most of my problems is the inexperience at lathe. With these tips they will help out lot. So pics to come guys,thanks again


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## Shootymacshootface (Mar 9, 2020)

What talvare said, but I would make a few spring passes with say, .020 or more to go to get the feel of things. Variables like the diameter of the work, hardness, how deep of a cut you are taking, and sharpness of the tool will all have effect on how much comes off with a spring pass. You can creep up on you dimension from a distance and not spoil anything. Plus it will help you to get to know your lathe.


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## Lo-Fi (Mar 9, 2020)

Worth mentioning that spring passes don't always leave the best finish, particularly with carbide. I've taken to running spring passes as I go figuring how much spring I've got for a particular cut in whatever material, then shooting for the final dimension with a ~15 thou cut. I've achieved some lovely finished straight off the tool that way, but never off a spring pass as final. Thought I'd throw that in as it's something I've recently learned on my machine.


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## Kroll (Mar 10, 2020)

After reading this again I feel like ya'll know me cause that is what I was doing and getting a bad finish even of my rough passes. Terrible! Thanks for all this info,so in afternoon I went back at it,figuring how much that I need to take off to get finish OD. So being little on nervous side I minus .020 # on how many passes which I now taking about .030 per pass which got me to within I think .030. So I made one more pass with carbide insert then switch to the HSS that Doc gave me. Guys I have to say which I know finish is not a challenge for most but for me it is. But this time it looks good and finish is so smooth,which this is a first for me. Yahooo But I still need to take off .002 so at that point I shut it down for the day cause I wanted to be able to sleep. Today first going to turn the OD down for that bushing,then again check the fit for the coupling. Pic is for entertainment only Again guys thanks all this things sure makes a difference


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## Mike_Mac (Mar 10, 2020)

Hi, I'm no expert on lathe work, but if I want a really nice finish after turning, I spin the part in the lathe and use some emery cloth strip to clean up the surface. It is possibly not the thing to do, but it works for me.


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## Kroll (Mar 10, 2020)

Mac,two minds think alike. I don't know if its consider a sin in machinist world but I needed to remove just a tad off the OD. I just did not want to tap the gear on nor the bushing. So I use some fine emery cloth to bring it down just so that I could slide the bushing and the gear on and call it good. So far so good,the bushing is on but still need to adjust the length for it. Do the same for the gear,which my plan is to use the parting tool just to square up the shoulders for both. Taking a break and to collect my thoughts and to check my game plan and to look at the drawing that came with PF


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## Mike_Mac (Mar 10, 2020)

It took me ages to get used to machining down to a given diameter. Once you get to know your lathe better you will master it. I have recently made 8 off bronze bushes. The material was expensive to buy and I didn't want to have any 'duff ones'. The first two I messed up with the boring to the correct diameter (too large) but then it all worked out OK with the rest and I had about a 2" length of material left.


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## DavidR8 (Mar 10, 2020)

Kroll said:


> Mac,two minds think alike. I don't know if its consider a sin in machinist world but I needed to remove just a tad off the OD. I just did not want to tap the gear on nor the bushing. So I use some fine emery cloth to bring it down just so that I could slide the bushing and the gear on and call it good. So far so good,the bushing is on but still need to adjust the length for it. Do the same for the gear,which my plan is to use the parting tool just to square up the shoulders for both. Taking a break and to collect my thoughts and to check my game plan and to look at the drawing that came with PF


Well done! that looks really great and if the fit is nice I'd call that a success!


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## markba633csi (Mar 10, 2020)

It's very common practice to use a file or emery cloth to bring a shaft to a precise dimension- I do it fairly often myself since my lathe is a "noodle" (Atlas, very wiggly and springy)
-Mark


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## Kroll (Mar 10, 2020)

Thanks guys, not counting my chickens yet but! So far so good,going to thread(using die) for the nut to hold the handle next then I be able to at least get one end at correct length. I know this is my chance to thread for first time using the lathe but that is an unproven area for my lathe. I need to practice first.


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## Mike_Mac (Mar 11, 2020)

Single point threading on the lathe is more accurate than using a die. Have a practise on some scrap first. It concerned me at first, cutting threads on the lathe, now I have started enjoying it. Have a look at a few videos, rather than just one video. There seem to be some different ideas on the subject out there. Pick one that works the best for you and your machine.

This guy has been a good  mentor for me and he has helped me a lot with my machining queries.









						My 1910 Mitchell "parts car" project
					






					forums.aaca.org
				




He has very old machines, but does some fantastic work on them.


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## Kroll (Mar 11, 2020)

Guys small steps for me,I believe that I am finish with this end of the shaft and it looks like all is good. Now I have to cut the shaft to length plus little then fine tune the length. Hope that the shims will help with fine tuning. Any advice,I'm on break right now


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## Kroll (Mar 11, 2020)

Projectnut-When you made your coupling does it but up against the roller bearing?I just measure length for my coupling it looks like it needs to be 3” long to butt against roller bearing.One I have is to short if this is case,so another project I guess


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## projectnut (Mar 11, 2020)

Kroll said:


> Projectnut-When you made your coupling does it but up against the roller bearing?I just measure length for my coupling it looks like it needs to be 3” long to butt against roller bearing.One I have is to short if this is case,so another project I guess



No.  My coupling sits tight against the threads on the lead screw and leaves about 1/4" of the shaft showing between it and the back of the plate the power feed is attached to.  The coupling I replaced was 2 1/4" long and would rub against the back of the mounting plate.  I don't see any need to extend the coupling through the plate to the  bearing.


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## Kroll (Mar 11, 2020)

Thank goodness,I was getting nervous.Back to plan A. Thanks for responding so quickly,off this week hoping to finish this


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## Kroll (Mar 11, 2020)

Guys now that I know that don’t need make another coupling it’s time move on to next step.Thats figuring out the shims that goes between roller bearing and the brass gear.How does person tell when it’s good fit? Na I’m not almost finish,I still have cut key ways for the new shaft at coupling and the key way for brass gear. Cutting key ways be first for me so going watch few YouTube’s before give it try.


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## Kroll (Mar 11, 2020)

Guys after reading Projectnut response I am clear to go. Then thinking about my question if you look on shaft there is a .812 OD then for the bushing that fits in the roller bearings OD is .790 I believe so that shoulder is what keeps the bushing from working its way towards the coupling. Today I was able to fit the new shaft with the coupling using the taper pin to connect the two.Thank goodness for DRO's and guys here who help me with that project. So for bout 10th time install the PF with all the parts, so what is left for me to do is cut the key way for the brass gear then drill a hole for a roll pin for the handle to the shaft. Finally pretty up the end where the nut goes. In this pic I power it up just to hear it run,so far so good.


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## Kroll (Mar 12, 2020)

What a way to start the day,well setting up to cut the key way in shaft which I was thinking that its 1/8 but its not. Checking it with my key set and nothing fits,so close but so far. So I get my gage block set(that's missing few) started checking and the .119 is a winner. But wait, .119 what kind of size is that .119 so I went metric shopping found nothing. So that leaves me with broaching an 1/8 key way but I don't think my set is for that deep of a key way. Checking


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## projectnut (Mar 14, 2020)

One more update on the X power feed on my Bridgeport.  When unpacking all the pieces I was growling that it seemed I was missing a couple.  After searching high and low I finally did find everything I needed.  On the you tube installation clip they show about a 1" black spacer that fits between the brass gear and the handle.  On the later models the brass gear is extended and the spacer is unnecessary.  

That was fairly obvious, but it still seemed the extension shaft from the original lead screw to the manual crank handle was a bit too short.  I finally found the replacement nut that secures the handle to the shaft hiding in the corner of the box.  With the power feed the handle no longer sits flush with the threads, but slightly overlaps them.  When I was using the original nut to secure the handle there would be a few threads left showing due to the repositioning of the handle.  The new nut actually slides inside the bore of the handle, so when it's properly installed there are no unused threads.


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## mmcmdl (Mar 14, 2020)

Kroll said:


> 119 is a winner.



3mm .


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## Kroll (Mar 15, 2020)

I be dang metric,McMaster sells them. Correction,smallest one they sell is 4mm. Wonder why 3mm, why not something more normal? Thanks never gave mm a thought.


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## mmcmdl (Mar 15, 2020)

You need one ?


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## Kroll (Mar 15, 2020)

Good morning mmcmdl, not sir I am going to broach it to 1/8 which is the size that I mill in shaft for a key way. Broaching is kinda new to me so looking forward to this. I done it once with 3/16 but that was couple yrs ago,so get to do this again Thank you for your offer


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## mmcmdl (Mar 15, 2020)

OK . We got whatever you need if not . I'll lend them out .


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## Lo-Fi (Mar 15, 2020)

Thought about making an arbor that fits the ID nicely and flush with the surface, drilling straight down between them so you end up with a semi circle keyway, then finishing square with a file? I've shaped similar single point with the lathe topslide and mill quill feed too.


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## Kroll (Mar 19, 2020)

Good morning guys,progress has been made.My broaching set showed up so I went to work.First thing I had to do is make bushing the length of the bore.Which that took while cause I wanted it to fit (for change) Well I be finally made this then mill for broach but I went bout .020 to deep.Ok I was going to make shims since learning little more about broaching key way.So one of these is .062,and others are.020.I only used the 3 .020 shims so all is good.Going put these in pack put them in my box till next time.Guys the key was little to big so did some wet sanding till all slide together.Dang this little part was lot work but I’m smiling.Guy thanks for all help suggestions on my other post,so now it’s time to decide is I should pin the handle or mill flat spot for set screw.


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## Kroll (Mar 19, 2020)

Guys,I think I am finish. Taken it for little test drive listening for sound of grinding gears but don't hear it. I think I just started with 3 spacers then turn it by hand seems good so I went with that. After putting all together I send table one way then another and change speeds. Sounds good,but I really don't know one way or the other. I just need to install the switch for table stops then support the wiring then I will be 100% finish. This is one little project that really tested me in several area's but with ya'll help all went well. Slow but I wasn't punching clock on this project. And for once I made a shaft that had to fit,and there is no sloppy fit  so that is good.


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