Gear Rack

[MattM]

I have a project that requires a 14" DP 12 gear rack. Cutting a gear rack is no problem. The problem is my horizontal mill will only accommodate a 7" rack. Cutting the pinion is no problem.

Any suggestions? I wouldn't mind buying an OTC rack if I could find one.

 

[markba633csi]

Can you cut the rack in sections? Not clear why you are limited in length on your mill

 

[MattM]

The Y travel is only 7". I would like to have it all in one piece for ease of assembly. If successful I may be making more than one of these.

 

[RJSakowski]

If you cut a short section of rack for a reference. You can mate it with the previously cut rack and use it to index the rack to a new position for cutting additional teeth. Depending on your layout, it may take some ingenuity on your part to set up the reference rack.

McMaster Carr sells 12 d.p. rack in both 14.5º and 20º pressure angles.

 

[markba633csi]

Edit: my thinking was goofed up- never mind

 

[dbb-the-bruce]

I've cut gear rack on my lathe using a mandrel and a milling attachment on the carriage. Made a specific gauge block for the pitch. Set stop, cut tooth, use gage block to advance carriage to the next tooth. I guess that doing a full 14" would require a 28" plus bed and a really long mandrel. Or maybe work up a custom tail stock that would stay out of the way?

Would be a challenge to do. Just buy the rack unless you funds limited or like challenges.

 

[dbb-the-bruce]

So you orient the rack parallel with the table and cut the teeth with the Y axis. Move to the next tooth with the X axis.

It's a horizontal mill, I don't see how you could do this. Cutter is spinning on y axis.

Can't you do 7" and then flip the rack around and do the other 7? (something like that)

 

[MattM]

I would like the rack to be integral to the ram which is the heart of the machine. I suppose I could buy an OTC rack, cut a channel in the ram and fasten the rack in it someway.

I'm going to check McMaster Carr.

 

[f350ca]

Good excuse to uy a shaper.


The plates bolted to the table had dowel pins to index the stock to the predrilled holes in the rack. You could do the same across the table of your mill.

Greg

 

[dbb-the-bruce]

if you can find/afford one... There is another recent thread about this.
ps. If you are anywhere in the north east US and have a shaper for sale pm me.