# Making A Flat On A Shaft



## HolyHarp (Aug 21, 2015)

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.


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## mikey (Aug 21, 2015)

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.


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## Charles Spencer (Aug 21, 2015)

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.


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## Jeff M (Aug 21, 2015)

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.


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## Fabrickator (Aug 21, 2015)

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.


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## Round in circles (Aug 21, 2015)

mikey said:


> 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 "?


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## Round in circles (Aug 21, 2015)

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 ).


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## HolyHarp (Aug 23, 2015)

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.


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## Wheresmywrench? (Aug 23, 2015)

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.


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## aametalmaster (Aug 23, 2015)

HolyHarp said:


> 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


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## HolyHarp (Aug 24, 2015)

That's an interesting way to adjust your tool post height.  I never thought of that.  Thanks for expanding my thinking.


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## Round in circles (Aug 24, 2015)

aametalmaster said:


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



  Now that has stirred the old grey matter  Bob.

I guess that it would not be too difficult to use a home made shallow aluminium vee block and one of the empty QCTP tool holders plus a G or F clamp to be able to raise and lower  something held in such a clamping system .


Sort of make a mini temporary lathe mill for you not only get travel across and back and forth over  the lathe bed you can get about 1.5  " vertical travel fairly easy by adjusting the tool holder height with the adjusting screws.

Thinking aloud.
I'm going to give that a go to see If I can get the flats I need , either on the QCTP or better still , I have a surplus  mono block tool holder  in machined steel similar to your tool holder.


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## aametalmaster (Aug 24, 2015)

I have milled like that for years. In fact I don't even use my little mill its easier in the lathe. I made a small angle plate that takes place of the compound and I use it for whatever my tool post can't handle which is perfect for keyways..Bob


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## Round in circles (Aug 24, 2015)

It's 23.34 hrs Uk time I've been up since 05'10 hrs this morning , how the hell do you expect me to go to sleep with all that stuff twirling round in my head.

 I've just had a thunk about using a bit of 1/2inch  steel plate and  putting in two high tensile 16 mm studs in it where the pinch bolts hold your frame anchoring it to the compound slot or the cross slide slot with one piece two studded plate  suitably  sized and precision fitted in the slots .

I can readily see that having a tower on each long stud made up of of precision flat washers or quality precision nuts  to set diameters would allow me to move work up & down very easily . It may also lead to some " U " bolts being used to clamp round bar to a back plate that goes on the stud tower  or drilled out square bar with holes and thread holes where needed.


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## Bill Gruby (Aug 24, 2015)

The Filing Rest is a very simple method. There is a kit for making one from Hemingway in the UK.


http://www.hemingwaykits.com/acatalog/Precision_Filing_Rest.html

 "Billy G"


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## David S (Aug 25, 2015)

Mine isn't as fancy as Bill's link, but it works for me.  I use the adjustment in the QCTP to vary the height.
David


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## Bill Gruby (Aug 25, 2015)

That one is cute David. I'll bet it works just fine.

 "Billy G"


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## RJSakowski (Aug 25, 2015)

Bill Gruby said:


> The Filing Rest is a very simple method. There is a kit for making one from Hemingway in the UK.
> 
> 
> http://www.hemingwaykits.com/acatalog/Precision_Filing_Rest.html
> ...


That's an interesting tool, Billy G, 

It looks like a great solution for those who don't have milling capability.  I have always like hand filing.  There is a certain satisfaction that comes from the intimate contact with your work that you can't achieve with power tools.

Bob


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## chips&more (Aug 25, 2015)

Thanks for the link, I have not seen that file rest design before. If you do any kind of watch/clock repair with a like lathe. The file rest is a must have accessory for it...Dave.


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## Andre (Aug 25, 2015)

When using a file to create a flat, I find it helps to rough it out then use a sharpie to mark the flat. Once marked, file just the center of the flat. Re-dye, then keep aiming for only filing the center of the flat. Should get it close for a set screw flat, and since it'll probably be in a pulley nobody will see it.


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## tq60 (Aug 25, 2015)

You also can place round stock in lathe bigger than on of shaft then bore through with a slip fit the size of the shaft.

Use a sharp hss cutter in tool post to scribe alignment marks on face of stock by just moving tool same as facing but with stock stopped.

On one make scratch along side.

Tip of cutter must be on center.

Maybe face first so you can get the tip on center then make marks and bore last.

Use square from bed and rotate 90 degrees and mark again.

Use vice on drill press to hold and use scratches to verify square and place side scratch top.

Center punch on scratch and carefully drill hole into center bore.

Set screws usually have pointed tip so select a drill that has same size to make a landing or seat and drill hole with that size.

Slide shaft into your sleeve and test to verify it is landing on center.

Now drill the seat and the set screw will land in seat and the fit will be great.

You can do same without the sleeve to use as a guide but the sleeve makes it easy to repeat without much work and you can practice your skills and make a tool at same time.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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