Do you know how to take this off?

[canadianoptician]

We are trying to take off the head where the lap is being held on our Coburn 5000 cylinder machine. I have taken the top screw out. The head is stuck on the post. I have also removed the front pincher plate.

we have the manual but it is not very clear.

I have attached some photos

Any help would be much appreciated.

[Leo Hadley Jr]

Its been a while, but I believe there is a large nut under the table that requires a special wrench. The nut forces the table up off the shaft.

[canadianoptician]

Under the table?
So open the front door and reach under??

[lensmanmd]

We are trying to take off the head where the lap is being held on our Coburn 5000 cylinder machine. I have taken the top screw out. The head is stuck on the post. I have also removed the front pincher plate.

we have the manual but it is not very clear.

I have attached some photos

Any help would be much appreciated.

[ATTACH=CONFIG]15143[/ATTACH][ATTACH=CONFIG]15143[/ATTACH]

I haven’t worked on a Coburn finer/polisher for close to 2 decades. But, if memory serves me well, there is a 2-1/2”, or so, nut underneath that requires a spanner wrench. You will most likely need to
drench that nut with liquid wrench to free it up. There’s always a mallet as a last resort.

[Leo Hadley Jr]

No, Under the table in the sink.
Its a large nut that goes up and down the shaft. You didn't need to remove the pincher plate.

[Leo Hadley Jr]

Under the table?
So open the front door and reach under??

No, Under the table in the sink.
Its a large nut that goes up and down the shaft. You didn't need to remove the pincher plate.

[canadianoptician]

Under this?

[Leo Hadley Jr]

Under the table?
So open the front door and reach under??

You can stick your fingers under the table and baffle and you will feel it.
When you loosen the nut with spanner wrench, you will be pushing the table up the shaft. Before reinstalling, put the nut all the way down.
I highly recommed spraying some PB Blaster or penetrating oil down the table hole to loosen it up. It looks to be in really bad condition.
You also need to change those pins!!!
Needs 100% maintenance to get it back to good running condition.

[Leo Hadley Jr]

Under this?

[ATTACH=CONFIG]15144[/ATTACH]

Under the rubber baffles. You can touch it with your fingers from above

[canadianoptician]

Thank you very much! I will try that

[Leo Hadley Jr]

Thank you very much! I will try that

You will need the spanner wrench, new baffles, pins, and the axis block to get it all perfect.
If you want to call me tomorrow, I could probably walk you through what I remember. Its been almost 20 years since I've done it.

[PRECISIONLAB]

To remove lap table first remove the allen bolt collar on to the table. Next use a "jack bolt" and screw into top of table and tighten until the lap table breaks loose. It's usually a 10mm similar to this which should be available at your local hardware store. See the threads by the top of lap table.


Metric tap bolts, Stainless steel 18-8 (A-2), 10mm x 1.5mm x 100mm - Bolt Depot

The larger bolt referenced requiring the spanner wrench is actually securing the bearing in place and is not holding the lap table directly.

[Leo Hadley Jr]

YES!!! I remember the jack bolt! Thanks... Its been a long time for me

[Don Gilman]

To remove lap table first remove the allen bolt collar on to the table. Next use a "jack bolt" and screw into top of table and tighten until the lap table breaks loose. It's usually a 10mm similar to this which should be available at your local hardware store. See the threads by the top of lap table.


Metric tap bolts, Stainless steel 18-8 (A-2), 10mm x 1.5mm x 100mm - Bolt Depot

The larger bolt referenced requiring the spanner wrench is actually securing the bearing in place and is not holding the lap table directly.

This looks very similar to the lap table on our FastGrind machine and precision lab is correct. You need a jacking screw which will screw in and bottom out on the shaft. Continue turning it and in theory the lab holder will move up. as mentioned by others a lot of liquid wrench and a couple wacks on either side will help to break it loose. Last resort heat the holder but you will ruin the baffles.