internal 6side

[Lorenz]

hello,

How can I make an internal 6 side in alluminium?
I have make an sketch (in mm.) from the idea in autocad:


(click for enlarge the picture and when the link is opened, click again on the picture)

the point is, I have to make it without a milling machine!
I can make it with a lathe, but i don't have a milling machine.

I was thinking.. i can drill some smal holes on every point on the internal 6 side.
than turn the circel in the 6side so far as possible?
and the rest with handtools?

i mean this way:


first the green small holes, and than turning out the big hole? than the handtools?

or is there a trick for doing things like this?

thanks!

greetings from Holland

 

[bob ward]

Lorenz, your proposed method of doing this in a lathe, ie no mill, is about all you can do.

To clean up the sides after drilling, make up a sharp ended tool the same height as the side of the hex and mount it in the tool post. Set the tool in the carriage so it will take a very fine cut off the inside of the hex, run the tool through the hex, take it back out, wind it over a little on the cross slide and repeat.

Sort of like cutting internal keyways as mentioned in this thread. http://www.homemodelenginemachinist.com/index.php?topic=3179.0

The tricky part is accurately indexing the hex by 60° to cut the next side, but even if you are doing it by eye, it won't be any more inaccurate than hand filing out the remaining material.

 

[joeby]

Lorenz,

Bob has already summed it up for the most part; but I would suppose that you have a mating part to this?

You could go ahead as planned by drilling the corners and boring out close to size. Lay out the hex beforehand.

Start working out to your layout lines with a file, intentionally tapering the flats so the hex is smaller on the back side until the mating part will start into the hole. You can then work at filing away the taper, not touching the front edge where the part fits, using your mating part as a gage.

Takes time, but you can normally see your contact points as a line around the inside of the hole. Use these as a guide and you can end up with a fairly close fitting part.

Kevin

 

[Metal Butcher]

I made a spider handle hub for my millimg vice that needed a hexagonal hole to fit over the odd size end of the vises screw. I machined down a piece of steel into a hex to match the dimensions of the screws end on the vise. I moved the table on my mill the width of the spider hub width and milled the hex down .010". moved over again and lowerd the cut again. I ended up with a six sided one time use broach that I hammered through a round pre-drilled block of aluminum to make the hub for my vise "spider handle". If it started to jam up I backed it out and filled out the burr created by the broaches cutting edges. To create a useable cutting edge on the broach the milling was done using a dovetail cutter.

There are probably better ways, but I got the job finished and enjoy the three knob spider handle on my vise. Its easy to spin the vise open quickly for cleaning out swarf.

I went back and re-read you post saying you do not have milling machine. No problem, you can use a file to create the steps just about as fast as the mill would when you consider the set up and time spent on indexing. You would need to start with the proper size hex.

-MB

 

[Richard1]

If you have access to a press make a 6 sided broach and push it though the hole that you have already drilled and bored as in your second image. I have done this in smaller sizes just using a bit cut off the end of an Allen key.

Richard.

 

[Powder keg]

I needed an odd sized internal hexagon for part of a drive mechanism for a riding lawn mower one time. I cut a socket apart and welded it into the part I made. Worked perfect)

 

[Lorenz]

thanks for the usefull reactions!

now I know that this is the way for make it without a milling machine!

it's clearly,

thanks for the reaktions!

greetings.