Making A Flat On A Shaft

[HolyHarp]

How do you make a nice flat on a shaft (a landing place for a set screw)? I know I can grind or file -- these methods work OK but don't look so nice and are not too consistent. I don't have a mill - That's probably the nicest way to make a flat. I just have a lathe.

 

[mikey]

A filing rest is probably what you're looking for. A long time ago I had to do what you are looking to do and simply drilled a hole in the edge of a block of wood. Then I cut part of the thickness of and sanded it flat. With the rod in the hole and the block clamped in a vise it was stable enough to let me file the rod down to the surface of the wood and I got a fairly good flat. Good old pre-mill days.

 

[Charles Spencer]

Do you have a boring bar holder that will fit the shaft? Or any way of holding the shaft on the center line such as an angle plate?

If so then you can use an end mill in a collet to make your flat.

 

[Jeff M]

The first milling machine was made on a lathe. You can mill from the spindle like Charles says. Lock your carriage and move your compound all the way out somewhat snug to get the most rigidity you can. If you have a QCTP you can put the shaft in any toolholder that it will fit. Just make sure your cutting edge is straight up. I would reccommend as small an endmill you can use to cover the flat width as the smaller the endmill, the less it grabs/pulls.

 

[Fabrickator]

Use your lathe. Depending on the size of the shaft and length of the flat, you mount a cheap milling tool bit (3/8"?) in the chuck and mount the shaft on the cross-feed and/or on the compound and mill it off. I've done this before and it works great.

Now, if the shaft is 2" O.D. it will be too high to match the center height of the lathe chuck/tool bit. But for a normal 1/2" to 1", it should be fine depending on the size of your lathe.

 

[Round in circles]

A filing rest is probably what you're looking for. A long time ago I had to do what you are looking to do and simply drilled a hole in the edge of a block of wood. Then I cut part of the thickness of and sanded it flat. With the rod in the hole and the block clamped in a vise it was stable enough to let me file the rod down to the surface of the wood and I got a fairly good flat. Good old pre-mill days.

A few weeks ago I was at a the Welsh National Slate Mine Museum here in Wales UK . In their still working machine shop they had a circa 1903 Cincinnati vertical mill /drill that weighed in at about 17 ton it stood about 12 feet tall , the table was big enough to sleep on .... are you that old "?

 

[Round in circles]

Thanks for the ideas of cutting the flats on round bar .. I'll be doing just that fairly soon , hopefully when I make a new spindle & new carriers ( with roller bearings this time ) for my cross shaft ).

 

[HolyHarp]

There are some great ideas here. I don't have a QCTP or angle plate (some day . . . ). I like the hole in wooden block idea - very simple. It must be a different hole for each shaft size. I'm tempted to put a vertical split in the wood so that it clamps the shaft so it won't turn. Thanks machinists.

 

[Wheresmywrench?]

You could also use 2 pieces of angle iron and a couple bolts and fashion a vice like clamp that will adjust to different diameters of shaft. Just drop in a couple inserts for width and depth of slot and away you go. Could be a little more useful in your local.

 

[aametalmaster]

How do you make a nice flat on a shaft (a landing place for a set screw)? I know I can grind or file -- these methods work OK but don't look so nice and are not too consistent. I don't have a mill - That's probably the nicest way to make a flat. I just have a lathe.

Here is how I do it with my lathe...Bob