Tightness and backlash in a Criterion DBL-202

1

11andrew11

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HI All,

I picked up a Criterion DBL-202 and DBL-103 in a local machine shop auction. I haven't used them yet, but I did take them both completely apart, cleaned them, and lubricated them with Vactra 2.

These are my first boring heads, so I'm not sure how tight the ways are supposed to be. Both move smoothly throughout their travel range, however the DBL-202 exhibits just a bit of tightness as the bar holder travels the 1/4" nearest to the 0 mark. Also, there is a small squeak in that range. I've lubricated the ways and the dial, but this continues. I've completely loosened the gib screws and also tried them with minor torque. Just looking at the ways, I can see that the ways on the body are slightly narrower at the dial end, when compared to the opposite end of the ways.

Is this normal? I wouldn't have thought about it except tha the DBL-103 does not exhibit this same tightness.

Also, what is a reasonable amount of backlash for a boring head? The DBL-103 has about 5 ticks and the DBL-202 has about 15. It would appear that backlash occurs as the dial wears in the two groves.

Thanks,

Andrew
 
As far as tightness of the dovetail, they should normally be pretty snug and have some resistance felt on the screw. Tighten the center gib screw when using.

Squeak? That's not right. Time to tear down again and find out where the problem is at.

The backlash seem pretty normal.
 
JimDawson said:
As far as tightness of the dovetail, they should normally be pretty snug and have some resistance felt on the screw. Tighten the center gib screw when using.

Squeak? That's not right. Time to tear down again and find out where the problem is at.

The backlash seem pretty normal.
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Thank you Jim. I really appreciate it.

I figured out the strange squeaking issue. It was coming from the allen wrench, which was a T-type wrench with a rubberized handle. I tried a different L-type and it did not squeak. I also tried a socket wrench and it didn't squeak either. Back to the T-type wrench and it squeaked. I think perhaps it was the harmonics of the T-wrench that was making the squeaking sound.
 
Just so you know, the recommended lubricant for Criterion heads was grease, not way oil. SuperLube is a good synthetic grease that works well and does not harden or cake with age.

The two outer gib screws are intended to give a very slight drag when the leadscrew is turned. Back off on all three and bring one end screw in until you can feel a very slight drag on the leadscrew. Repeat for the other end screw. The two end screws do not need to be touched unless play develops. The center screw is only used to lock the position of the sliding part of the head; it is not used to adjust gib contact.

Backlash is not an issue if you turn clockwise to advance the head. The leadscrew is a class 3A thread and if you advance CW and then lock the center gib screw there should be no backlash at all.
 
mikey said:
Just so you know, the recommended lubricant for Criterion heads was grease, not way oil. SuperLube is a good synthetic grease that works well and does not harden or cake with age.
Click to expand...
Awesome! Thanks so much. Is there more than one type of SuperLube and, if so, which would you recommend?
 
A little bit goes a long way so don't overdo it.
 
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