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10K Leadscrew Reverse Lever Installed on 9" ABC

FTF Engineering

Hot Rolled
Joined
Oct 30, 2003
Location
Philadelphia, PA
I recently installed a 10K leadscrew reverse lever onto my 9" Model A and thought I would share some pics I took during the process.

This is the 10K reverse lever that I started with.

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Here's the plate I made that spaces the 10K gears out where they belong. This one is my template made out of aluminum for ease of machining, but I intend to replace it with a steel version.

2.jpg


I calculated the required thickness of the plate by measuring and subtracting the difference between the locating surfaces of the 10K and the original 9" reverse lever. I came up with 0.355 and that's how thick I made the plate. However, after making it to 0.355, I discovered that the geometry is a little more complicated than that and the spring loaded pin for forward/neutral/reverse didn't end up in the center of the edge of the plate. I ended up making a washer to space the gear assembly out a little farther from the headstock to compensate and I'll make my final plate a little thicker to fix this and make the washer unnecessary.

I came up with the following to drill the locator holes for Fwd/Neut/Rev. First, I took the pull knob off the 10K lever:

3.jpg


The knob is held on by a pin which was filed flush at the factory. The pin is not tapered but it can be hard to find.

Next, I made two drill guide bushings each one 1.60" long with an OD of 3/8. One of the guides has a 1/8" hole through and the other has a 1/4" hole through and they look like this. The tape on the drill bits is my fancy depth guide.

4.jpg


The bushing slips into the hole where the pull knob goes and acts as a guide for the drill bit to locate the holes. In use it looks like this:

5.jpg


In order to establish the correct gear lash, I slipped a piece of universally available precision gear mesh determining shim (AKA newspaper) between the gears and then held the assembly in place with a bar clamp (not shown in the photo) around the headstock while I drilled the holes. First the smaller pilot hole, and then the final 1/4" hole.

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7.jpg


Here's the finished template and it works great. I hope to have the steel one made soon. Don't mind the extra mounting hole. I had to move it once because I screwed up.

8.jpg


Hope that helps! -Bruce
 
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Bruce: Thanks alot, that really helps. Nice work! How thick is your plate and washer total? Do you think that if you just keep the Alu. plate it would hold up OK? The reasion I ask is that I have some Alu. on hand but I would need to hunt up some steel. Gary P. Hansen
 
Hi Gary,

Glad to help. Hope this makes your job a little easier.

I don't remember offhand how thick the washer was, but I'll check later on today and post again tonight.

In theory, there should be a "perfect" plate thickness whereby the holes would end up centered in the final project. I'll take some measurements and calculate that as well.

I think if you used a good hard grade of aluminum it would hold up OK. Since I wasn't planning to use it forever, I just grabbed something out of my scrap box that was close to the correct size. I have no idea what grade mine was but I could tell from the machining that it wasn't a high grade. I'm certainly no materials expert, but 6061-T6 would probably last for a good long time. Eventually the holes will waller out, but I think I would be dust by the time that happened.

Something I didn't mention before was that the large hole where the reverse lever goes through the plate is an unusual size (something like 1.06"). Of course, I didn't have a drill that size, so I started with a large round disk of aluminum and bored that large hole on the lathe. I mounted the disk off center in my four jaw chuck and bored the hole to size. I didn't take any pictures of this part of the process but it was pretty simple. The neat part about doing it that way was I was also able to face the disk to thickness on the lathe. Of course, knowing what I do now, I would have done a little less facing and left the plate thicker...
The smaller hole I put in with a drill bit in the drill press.

Something else I didn't mention before is that the hex headed bolt that holds the assy to the headstock was modified to fit. The head of this bolt has to fit between the handle and the plate and the head on a normal bolt was to thick and hit the change lever. To deal with this, I chucked the bolt up in the lathe and faced the head to make it a lower profile so it would fit under the handle.

Hope that helps some more and I'll get the rest of those measurements for you later.

-Bruce
 
I measured the washer and got 0.045. With that in mind, a plate thickness of 0.400 should do you pretty well.

I also calculated the thickness that should end up resulting in the holes being centered in the edge of the plate and came up with 0.410.

When I get the chance, I'll try to take some additional pics of this area and maybe make up a drawing showing how I calculated that 0.410 plate thickness.

Hope that helps and please let me know if there are any other questions.

-Bruce
 
Bruce,

Thanks for taking the time to document your project. Looks good! I like that type of reversing mechanism much better than the older style (though the modification seems a bit radical for my '47). I got spoiled by my 10K, which had the knob-style lever as well.

Nice work!

Paula
 
"... I slipped a piece of universally available precision gear mesh determining shim (AKA newspaper) between the gears ..."

For super-precision lathes, one needs a super-precision shim.

"Funny cigarette" paper might be a good choice.

Come to think of it, in some areas, perhaps in the Humboldt County area of California, and in Southern Oregon, such cigarette paper may be more readily available than newspaper ;) .
 
10K Leadscrew Reverse Lever - My experience

Though I was reluctant at first, Bruce’s story has inspired me to do the same thing for my 9A lathe. It didn’t take much use of the lathe with the old style lever to realize how much I missed the convenience of the one on my 10k. I managed to find a suitable lever assembly on eBay, and wound up paying $43.00:

REVLVR3-1.jpg


The only problem with it was that it had a 16-tooth stud gear (for B and C models), rather than the 20-tooth, which my lathe needs. But since I was planning to use the original gears from my lathe anyway, this didn’t matter. The original gears are in much better shape.

The first thing I did was disassemble the reverse lever and clean it up. Removing the inner gear from the idler shaft can be a bit of a challenge -- it’s a fairly heavy press fit. In order to avoid damaging the threads on the end of the shaft, I made a small CRS cap, just under 9/16” dia. on the outside, and tapped 7/16-14 inside. It was just about all my little one-ton arbor press could handle to press the shaft out of the gear.

Disassembling the detent pin/knurled knob mechanism might be a problem only in that the pin which holds the knob to the pin is often very difficult to find on the O.D. of the knob. A clue can be had by looking into the center drilled hole in the end of the detent pin. The center of the locking pin should be slightly visible, giving an approximate location of where to look on the outside of the knob.

After disassembling the pin/knob, I stripped the old paint from the lever, re-painted it to match my lathe, and replaced the oil wicks. There should be a total of eight separate wicks, (3) of which are rectangular strips, and (5) that are 1/8” round. NOTE: when reassembling the twin gears, take care to assure that the wicks on the idler shaft-bolts line up with the feeder wicks on the face of the bracket. Also, make sure that the alignment doesn’t shift when tightening up the nuts on the shaft-bolts.

The first part to make was the detent plate. While Bruce made his out of aluminum to start with, his success led me to throw caution to the wind, and go straight to the steel. Besides, I had a ready scrap of 1/2 x 4” CRS, 4-1/2” long, and no suitable aluminum scraps to speak of. I wasn’t sure yet how large the detent plate should be, but I knew that my half-inch CRS plate would be ample, so I just chucked it up in the four-jaw. I had already determined that a thickness of .43” would center the detent holes, so I began facing the plate to thickness. I made a cleanup pass on one side before turning the plate over, and facing to the finished thickness:

PLATE1.jpg


The next step was to drill and bore for the the shank of the reverse bracket. Since I had plenty of plate to work with, I just located the hole right in the center of the plate. I used several size drill bits to get to 1”, and then a boring bar for final sizing:

PLATE2.jpg


I wanted the detent plate to more-or-less cover the existing boss on the headstock, and of course also provide the correct arc for the detent pin holes. I made a template on heavy paper to trace the outline onto the plate. I came up with a radius of 2-9/32” for the area where the detent pin holes would be drilled. I applied Dykem to the plate, and used the shank of the bracket to align the paper template on the plate. Then I traced around the template with a scriber:

PLATE3.jpg


Here’s what the detent plate looked like after sawing (Note that I left more material at the detent pin hole area, to make sure that it didn’t get undercut):

PLATE4.jpg


In order to finish the contour of the plate, I used a 3 x 21” DeWalt belt sander mounted in a stationary stand. It did a very nice job. The next step was to drill and counterbore for the mounting holes. I elected to use two 1/4” bolts instead of using the existing 3/8” threaded hole in the headstock. I didn’t like the location or size of the 3/8” hole, and felt that two smaller bolts, spread out a bit, would provide a more secure mounting. Here’s a picture of the plate mounted to the headstock, ready for drilling the detent pin holes:

PLATE6.jpg


For drilling the holes, I used the same brass bushing method that Bruce described above, only difference being that I cheaped out and used a single bushing for both hole sizes, enlarging the 1/8” hole to 1/4”. I also used Bruce’s “universally available precision gear mesh determining shim” to set the position of the reverse bracket. To hold the bracket in position for drilling, however, I was able to utilize a nifty arrangement. Some of you might remember that I installed a ball-nose spring detent for my original lever, and the handy 5/16-18 tapped hole provided an ideal location for a setscrew to hold the bracket in position while I drilled the holes.

To locate the hole for the neutral position, I simply measured between the two outer hole positions, and marked a point equidistant between them. I was a bit surprised how close together the three holes wound up being. I gave them a generous countersink to facilitate shifting from one position to the other.

It all worked out very well! Here are a couple of pictures showing the finished product:

FINLEVR1.jpg


FINLEVR.jpg


Thanks, Bruce, for providing the inspiration. This improvement will make my lathe just that much more pleasant to use!

Paula
 
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Paula, any chance you made a drawing for the detent cam on this project. I would love to make the cam while trying to find the reverse lever. I have bid several times on ebay but stopped the bidding when they approached $60, but I will eventually get one. Heck a CAD drawing would be perfect but even a pencil drawing with dimensions would be great.

Thanks!!

Great looking project, I can't take mine apart long enough to make it look as nice as yours. I use the thing way to much, always making antique Jeep parts for friends.
 
Yes, I have a drawing of the detent plate profile (see below). The dimensions are more or less arbitrary, and I suggest you verify them with your lathe. And your reverse lever bracket, when you get it. I was kind of surprised to see how high these levers were selling for on eBay. I think the reason I got mine as reasonably as I did was because of the 16-tooth stud gear.

Oh, one other thing... I don't have dimensions for the two 1/4-20 SHCS. I just placed them by eye. You could eyeball the locations close enough from the picture, if you decide to use that configuration.

Paula

DETENT2-1.jpg


[ 05-19-2007, 12:30 PM: Message edited by: Paula ]
 
Paula,

Superb work. Now that you've figured out how to make it look good, I can go back and finish mine. Like I said before, this is going to be my M.O. on any upcoming project. :D

So, for your two 1/4" cap screws, did you actually drill and tap into your headstock casting? That was something I avoided by using the existing mounting hole. Yeah, it probably isn't as secure of a mounting scheme, but I can tell you that I filed mine to fit and there isn't a lot of play in there. My headstock already has enough extraneous holes in it!!

To hold the bracket in position for drilling, however, I was able to utilize a nifty arrangement. Some of you might remember that I installed a ball-nose spring detent for my original lever, and the handy 5/16-18 tapped hole provided an ideal location for a setscrew to hold the bracket in position while I drilled the holes.
Hummmph. I used a big a$$ Jorgensen bar clamp from one end of the headstock to the other. Bubba told me he was proud of the ingenuity.
bubba.gif


Your mention of marking and drilling the holes reminds me... First time I was doing this, I made the mistake of centering the lever such that the gap between each of the two gears on the lever and the spindle gear was the same and then proceeded to drill my neutral hole. Problem was that when I then went to drill the other two holes, I found that the geometry makes it such that the neutral hole isn't anywhere near the center between the two other holes. I don't remember for sure, but it may have even overlapped with one of the other two holes. Really pissed me off too because I even went so far as to use a feeler gauge to get the gaps juuuuust right only to find out that it doesn't work that way. HAHA!!

What you should do is locate the two drive holes FIRST and then go back and center the neutral hole between them. The gaps between the three gears at the spindle won't all be even, but there will be enough clearance that it will be in neutral nonetheless. That's the lesson I learned that resulted in the second mounting hole in mine. Thankfully I had enough meat that I could cut off the mistake, spin it counterclockwise some, and try it again. Sorry I didn't mention that before and thankfully you didn't fall into that trap like I did.

Again, looks great and glad I could help in any way. You're going to love it.

-Bruce
 
I was kind of surprised to see how high these levers were selling for on eBay. I think the reason I got mine as reasonably as I did was because of the 16-tooth stud gear.
It's not because of the gear!! It's because everyone is snatching up the 10K levers and putting them on their older 9" lathes.

Whew... Glad I got to this one before market got all hot. :D
 
Whoa hold on there a minute.

What kind of drafting program does Paula use
that can spit out a .jpg file?

I've been trying to find that one for years
now. All I can get out of microcadam is
either bmps, dxf files, or postscript files.

Jim
 
Jim,

It's KeyCreator (Cadkey). But it actually saves the image as a .tif file. Then I open it in my image processor and save it as a .jpg file.

Paula
 
So, for your two 1/4" cap screws, did you actually drill and tap into your headstock casting? ...My headstock already has enough extraneous holes in it!!
Yes, I drilled and tapped the headstock.
Shock-and-Awe.gif
Well, there goes the museum artifact status.
Oh_Well.gif


Regarding the detent hole location for the neutral position, I'm sorry you got bit on this! I was aware of it already from when I was setting up the spring detent on the original lever. It's due to the twin gears being different distances from the pivot point. Still, I didn't really think about it till after I drilled the two outside holes, and noticed how close together they wound up. I guess it's a good thing I drilled them first!

Paula
 
Paula do you like the key creator? I'm still using my Cadkey 98, love it but it is kinda outdated now for some of the solid modeling stuff. I use Solid works and solid edge at work but still prefer my Cadkey for general drawing. My old Cadkey will save it as a gif or bmp along with all the other traditional cad files
 
Yes, I learned the hard way that locating the two drive holes first is the way to go. No problem on mine though... That's why it's a template. HAHA! I'll probably still be using that "template" ten years from now.

And you know... We're all going to have to stop calling this a "10K reverse lever" since South Bend started putting it on the 9" lathes as well in the 1960's. :D

Wasn't there someone else who recently did this mod as well?

garyphansen, Didn't you do this modification? And if so, were there any other pitfalls that weren't covered already?

-Bruce
 
Yes, I did. I think I paid about $43. on E-bay for my reversing lever. The forward gear of my new reversing lever was badly worn so I replaced it with the reverse gear from my origianl lever. I made one out of AL first then used it as a pattern to make one out of steel. (I think the one I made out of AL actually worked better. I adjusted my dimensions on the steel one maybe a little too much!) There is a little more gear noise in forward than in reverse.

Before I made the forward-reverse bracket I made an AL face plate to attach the bracket to for machining the outside diamater radius and boring out the 1.06" dia hole. I attached the bracket to my face plate using the same counter bored hole and a scoket head screw I used to attach the bracket to the lathe. (I drilled and tapped my face plate. Yes, I know I should have attached the bracket to the face plate in more than one place but it worked out all right anyway.) I think I chucked the screw in the lathe and used carbied to cut the bottom of the screw head back so the counter bored hole in the bracket did not need to be so deep. Anyway, the head of the screw is even with the surface of the bracket when it is installed on the lathe.

My brackets are not nearly as fancy as Paula's. Think of a 2"X3" rectangle with one of the 2" ends being a 2.125" radius.

The modification works great. My lathe does not jump out of gear anymore. Gary P. Hansen
 
"We're all going to have to stop calling this a "10K reverse lever" since South Bend started putting it on the 9" lathes as well in the 1960's."

My 1964 SBL 9A has this lever. I just took it for granted all 9's had it as well.

Jeff
 








 
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