Mounting L00 Adapter Plate To Chuck

[Joe Pitz]

Hello all,

When I purchased my lathe it had a 5C collect adapter mounted to the 6" 3 jaw chuck.
Several folks here on the forum indicated that this was not a safe way to mount the chuck and that I should change the mounting to an adapter. Since my lathe has a L00 spindle I picked up a 6" L00 adapter plate.

It just arrived yesterday, I have a few questions. Please refer to the below images.

The adapter has a step lathed on the mounting surface. The chuck has an relief also on the mating surface.

Unfortunately the step in the adapter is larger than the relief in the chuck.

The bolt holes in the adapter are way on the outside of the adapter and look that they are too wide to mount to the holes in the chuck.

The questions are, should I return the adapter plate?

Or should I turn the step down on the adapter to match the relief on the chuck?

Then drill holes in the adapter to match the holes in the chuck or drill new holes in the chuck and adapter plate?

What is the correct procedure to mount the adapter to the chuck to the run out is near .000"?

Here are the pics.

Thanks

Joe

 

[kd4gij]

Mount the adapter to your spindle and face it and machine the register to a snug fit for the collet chuck. Then drill the adapter to match your chuck.

 

[JimDawson]

The step on the adapter is called a register, the good news is that it is larger than the register pocket on the chuck. They are made oversize so you can custom fit to your chuck on your lathe.

Mount up the adapter on your spindle, then turn the resister for a very snug fit on your chuck. The width of the register should be a few thousandths less than the depth of the register pocket on the chuck, do not let it bottom. Face the flat surfaces on the adapter so those surfaces are true to your lathe. The chuck should fit tight to surface outside of the register.

Once that machining is complete, the it's a matter of drilling (and counter boring if needed) the mounting holes. It looks like you have a choice of a 3 or 4 bolt mount, the chuck seems to have both patterns. I might be temped to use the C5 adapter as a jig to transfer the hole location.

I'm a little confused about the C5 adapter, it seems to have threaded holes in the 4-bolt pattern as does the chuck. Not sure how the chuck was originally attached. I also see some divots in the chuck mounting surfaces, stone, file, or sand those raised areas flat. Just knock off the high spots.
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[Joe Pitz]

Thanks kd4gij,

Should I attempt use existing holes in the chuck or drill new holes directly through the adapter into the chuck?

If the answer is to match the existing holes, then should I disassemble the chuck and use a transfer punch to mark the drill holes?

What is the most accurate method.

Thanks

Joe

 

[Joe Pitz]

Thanks Jim,

It appears that the 4 bolts were just screwed into the chuck,, they were hard to remove as they were tight fitting.

Thanks

Joe

 

[JimDawson]

Disassembling the chuck would be a good option, it will give you a chance to clean it while you have it apart. Put a witness mark on the outside so you make sure the two halves go back together in the same orientation. Use some gear oil on all of the moving parts when you reassemble it, and stand out of the way when you first turn it on or you will get an oil bath. If the jaws and slots are not numbered then number them before you disassemble.

It does not look like the 4-bolt pattern is drilled through the back, but the 3-bolt pattern looks like it might be. You may not be able to use a transfer punch on the 4-bolt pattern without drilling the holes through after you get the chuck apart.

 

[Joe Pitz]

Jim, another issue,

On the L00 adapter the threaded hub that mounts to the spindle has a quite large diameter. I laid it on the chuck and the hub is just a bit too large as it covers part of the widest existing holes in the chuck.

See image.

Could you drill holes into the outer ring of the chuck to mount the adapter, shown on the previous images, with the hex bolts on the outer ring of the chuck?

Thanks

Joe

 

[JimDawson]

I might be tempted to use 3 of the existing bolts in the chuck outer rim if I couldn't use the inner bolt circle. Just get some longer bolts. Use either grade 8 hex bolts or socket head cap screws, which ever fits the application best. Make sure the new bolts are long enough, but not so long as to bottom. Buy long, and cut them off if you need to.

 

[Joe Pitz]

If the outer bolt holes are not drilled all the way through the chuck, (can't use a transfer punch) what is the preferred method to mark the holes in the adapter plate for accurate drilling.

Thanks

Joe

 

[JimDawson]

The outer bolts are through drilled. The have to be, they hold the two chuck halves together.

But they do make a blind hole transfer punch set.