Vn12 Bent Knee Feed Screw

[tq60]

Carefull with pressing as it may snap!

Think crank shaft from engine...

Text books shows huge press but now how we did it back in the day...

As a punk in 78 we straightened crank shafts that were welded and cam shafts for grinding.

Both are brittle so to speak but easy to do.

You place in v blocks or between centers and get a dial indicator to measure.

You will need a smaller to me dion ball pin hammer and a good chisel with a good v edge

There is one difficult thing to remember here...When you hit it the shaft will move TOWARDS the hammer!.

Place in centers and locate the high spot.

Place the high spot down then along the edge of the end of threads on any shoulders on top side hold chisel and gently tap it.

You are making a small v and that action relieves stress along with expanding the metal.

You tap about a third the way around and go slow as it takes practice.

We did 20 or so cams a day like this and they move quite a bit.

Remember to be gentle and measure often as the shaft moves with every smak.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

 

[gcaldicott]

Thanks for the help everyone. I had good success straightening the feed screw by making an aluminum block bored to fit the small end of the shaft and slit so that when clamped in the vise it held tight. I used two vises on my Jig borer table. One vise clamped the block/shaft in place and the other vise was used to put controlled force on the shaft to bend it back straight. I got it within .002" and called it good.

Here is the setup I used.


Greg

 

[gcaldicott]

Can someone please explain how inserting images is supposed to work. Half the time it works and the other half it doesn't...frustrating!

 

[gcaldicott]

 

[HMF]

All I do to insert images is hit the "Upload a File" button to upload a file with the image.

Choose the image file and it will upload.

Go to the place in your post where you want it.


Choose either Thumbnail or Full Image to the right of where it says "Attached Files" below the post.

So if I want the Thumbnail image here--->

I go there with the cursor and click on Thumbnail.

 

[FOMOGO]

Nice solution Greg. I was picturing a heavier screw in my mind. Cheers, Mike

 

[Cal Haines]

Thanks for the help everyone. I had good success straightening the feed screw by making an aluminum block bored to fit the small end of the shaft and slit so that when clamped in the vise it held tight. I used two vises on my Jig borer table. One vise clamped the block/shaft in place and the other vise was used to put controlled force on the shaft to bend it back straight. I got it within .002" and called it good.

Here is the setup I used.


Greg

Greg,

Nice job on the leadscrew!

I don't know what's going on with your photos. But when I do a reply to your message, the photo is there. ???! But then once I post the reply, the photo is gone again. . . .