cutting keyway on long shaft

[territorialmill]

Need to cut keyways on each end of 1/2 X 60" jack shaft that will ride on gear racks on plasma table. So the keyways have to be dead on in alignment. Shifting gear racks back and forth to get alignment doesn't seem to be best option. Any ideas on set-up/cutting would be greatly appreciated.

[Geof]

The simplest approach could be to make two 30" shafts with a keyway at one end and a split coupling in the middle to permit alignment of everything.

If you have to cut the keyway because there is no room for a coupling one way to align it is clamp a length of flat bar across at the middle of the shaft; you might need to make something to do this because the flat bar needs to be held on tight. Use a good machinist level to level this flat bar for each end and your precision is as good as you can align the level.

Alternatively you align the flat bar with a dial on a rigid support clamped onto your machine.

[mxtras]

What machine are you cutting the keyways on?

To do something like this on a standard Bridgeport, if you use two vises at the extreme edges of the table, you could rotate the turret and extend the ram to address such a length in one set-up but to get it spot on whould be a challenge to say the least and would take forever to properly set-up.

Have you investigated taper lock hubs for your pinions? Might be worth a look instead of using keys.

Scott

[One of Many]

One suggestion would be to make up some 1x1x6 blocks with a hole that the rod can pass through and a set screw to grip the rod. Place 3-4 blocks along the rod set on a common flat surface, then lock them all in position. Cut one end key, then flip the rod around to cut the other end, using the blocks as the alignment index.

You can do the same with V-blocks if you have several of the same size.

If the key way cut into the pinion gears are not indexed the exact same in relation to the teeth, it may make this a wasted of effort. As an alternative, you could place everything together with Keyless pinion gears, then after alignment, drill and tap into the end of the shaft/gear for a set screw where a key would normally go.

DC

[HuFlungDung]

On a small shaft, you can, if you have one, take a precision V block and clamp it to the top of your shaft, outboard of the table. Take your precision machinist's level and level across the V block.

Leave the V block in place.

Cut one keyway.

Then, reposition the shaft, relevel the V-block and cut the second keyway.

[mxtras]

Originally Posted by One of Many .... As an alternative, you could place everything together with Keyless pinion gears, then after alignment, drill and tap into the end of the shaft/gear for a set screw where a key would normally go. DC

Or drill and ream the intersection of the diameters between the pinion and the shaft (ID of pinion, OD of shaft) and tap in a solid pin.

Scott

[Geof]

Originally Posted by HuFlungDung ....Take your precision machinist's level and level across the V block. Leave the V block in place. Cut one keyway. Then, reposition the shaft, relevel the V-block and cut the second keyway.

Plagiarist.

[HuFlungDung]

I was eating breakfast, and didn't see a few posts after I started typing a reply, honest

[Geof]

Originally Posted by HuFlungDung I was eating breakfast, and didn't see a few posts after I started typing a reply, honest

You are how many times zones earlier than me but you have breakfast later!!! I wish I could afford to sleep in like that!!!!

[territorialmill]

Taper lock hub. Couldn't find them in that small of dia. Will look some more. Coupler - easiest- would need to be tight to avoid whipping at hi rpm-might work best if placed next to bearing block or gear. Like the idea of v-block-Like the idea of the challenge. Honestly, had to read that suggestion several times to figure out what was being said. As hobbiest with no formal training and, up to now, no one to ask for advise, I really do appreciate your suggestions. Thanks guys-I'll be back.........

[Geof]

Originally Posted by territorialmill ...Coupler - easiest- would need to be tight to avoid whipping at hi rpm-...

If you are driving a pinion fast enough to worry about a shaft whipping I don't want to stand near the end of the machine!!!!

[ctate2000]

Sorry, I typed an answer that was already given. It has been deleted. Clamping to v block and rotating was my answer.