My dremel 1680 starts out quiet but by the end of the cut banging like crazy

https://bels.soe.ucsc.edu/sites/default/files/Dremel%20Model%20160%20Scroll%20Saw%20Manual.pdf

Black is positive(+) and white negative(-).
Circuit board should be marked.

Neil, drilling it out will work, if you have access to a die grinder, or dremel tool with a small carbide bit, the nut could be cut fairly deep and finish splitting with a chisel.
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."

You will have to remove the plastic cap on the end of the tool where the tips go in. Then screw on the cutting guide.

go to this link might help you find out why... kenmore quiet pak 2 washer drum banging around Google Search

Check and replace brushes as necessary. Also, check that the actual electrical switch is functional. I had to add a drop of crazy glue on the tip of the interior plastic handle housing that supports/puts pressure on the electrical switch to keep it in position. The off/on thumb slider actually extends well into the housing and activates the electric switch by moving back and forth. Over time, the plastic wears and does not plunge the on off switch button. A drop of glue on the tip of the plastic post extends it & causes enough pressure to make the electric switch to function again. Brushes (filed to fit) and glue = good as new Dremel :o)

you can contact the service provider......

Lubrication

ARM BEARINGS

Lubricate the arm bearings with oil after 10 hours of use.

Re-oil after every 50 hours of use or whenever there is a

squeak coming from the bearings.

TO LUBRICATE

1. Turn saw on its side (Fig. 18).

2. Remove rubber plug to expose bronze bearing.

3. Squirt a generous amount of SAE 20 oil around the shaft

end and bronze bearing.

4. Let the oil soak in overnight in this condition.

5. Next day repeat the above procedure for the opposite
side of the saw.



You can get the manual on the link below. scrool down to product details to get it.

http://www.amazon.com/Dremel-1680-6-Horsepower-Benchtop-Variable/dp/B0000302YQ

Good Luck

Go to Dremel.com and they have a toll free number that you can call and also look at a break down for this tool, they will be able to help you with this problem. If I have helped youu with your question would you please rate this response accordingly. Thank you

REFERENCE M/N: 395 - Type 3 - Dremel does not have the parts listing on their site for some reason. I actually have the original I saved from 1988!
The part number for the Nylon Coupler is:
Illustration Code Number: 5
Description: Flex Coupling
Part Number: 529430970

This is all from Drawing (Form) Number:5296074 10-88