Looking for a rare chuck key

[Rich2502Participant @rich2502]

I’m looking for a Rohm S10 key with 7mm spigot , they are rare as the usual one is 6mm , has anyone got this key that fits nothing hanging about in a drawer ?  I have the one old model of Makita angle drill that uses it .

 

 

 

[peak4Participant @peak4]

Could you find one with a larger pin and turn it down, alternatively is there a Jacobs one which could be modified?
What chuck is it for?

[JasonBModerator @jasonb]

Could you just sleeve a 6mm one?

[Bo’sunParticipant @bosun58570]

Both peak4 and Jason’s ideas are valid, providing the teeth mesh correctly.  A tricky one until the spigot has been modified either way.

[Bo’sun]

On Bo’sun Said:

A tricky one until the spigot has been modified either way.

By my calculations 2 27/64 wraps of insulation tape on the 6mm spigot should bring it to 7mm, allowing a test fit to be made.

[JasonBModerator @jasonb]

You have got thicker tape than me😉

[bernard towersParticipant @bernardtowers37738]

Its on ZORO

[Howard LewisParticipant @howardlewis46836]

As suggested, turn down the 6 mm spigot to 5 mm and fit a sleeve which can THEN be turned down to 7 mm, (still only 1 mm wall).

OR if you can find a key where the gear is suitable, but with a larger spigot, turn than down to 7 mm

Howard

[Chris CrewParticipant @chriscrew66644]

I am looking for to rare chuck keys too. One for a Burnerd KC07 multi-size collet chuck and the other for a Burnerd KC10 multi-size collet chuck. Or, if anyone could advise me what the details are of the bevel gear on the closing ring of these chucks is I could possibly obtain a gear and make suitable keys.

[Chris Crew]

On Chris Crew Said:

One for a Burnerd KC07 multi-size collet chuck and the other for a Burnerd KC10 multi-size collet chuck.

I have just reverse engineered the key for a KC15 chuck. Clearly this is not what you need, but it might give you some ideas on how to proceed. For info., the KC15 key is 12 teeth and 12DP at the large end. The bevel gear on a KC15 chuck has 51 teeth.

I had a key to measure so that made the process faster but I think you could get the same result even without a key.

Measure the OD and count the number of teeth on the bevel gear on the chuck. You might have to dismantle it for the next measurement, but measure the angle (to the nearest two degrees would do) of the tooth tips relative to the axis of the chuck. That would be a starting point for the pitch cone angle of the bevel gear.

With those two measurements we can take a first stab at the number of teeth on the key and its DP. Using those numbers, it is easy to 3D model some likely candidates and 3D print them. Then you just try them one by one to see which is best or go around the loop again if none are suitable. Once you have the best fit plastic one of known specification, you can make a metal one.

It is vanishingly unlikely you will find a gear on sale anywhere that will fit. Bevel gears work as a pair so for gears meshing at a right angle the cone angle on the key must be the complement of that of the gear on the chuck. These two angles are determined by the tooth ratio of the pair.

Look at HPC’s range of bevel gears for a starting point. The sell single gears to suit 1:1 ratio and pairs of gears to suit maybe 1:2 and other simple ratios. The KC15 chuck is a low ratio and an odd one at that (4:17).

 

[old martParticipant @oldmart]

I had the similar problem with a pin that was undersize on the chuck and cut off the pin, removed the tommybar so it would chuck up in the lathe and drilled into the body of the key to press in a pin that was a nice fit in the chuck. The pin may have been stepped in diameter, I forget the details. Unfortunately that key has gone missing and won’t turn up until well after I give up looking for it.

[old mart]

On old mart Said:

…removed the tommy bar so it would chuck up in the lathe

I am trying to picture it in my mind but I think it might be possible to do similar without removing the bar if you had a six jaw chuck with two opposite jaws removed. Just putting it forward as an idea. The relative diameters of key and bar would influence if it would work.

[Author]

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