- Joined
- Oct 18, 2016
- Messages
- 2,872
When I removed the carriage on my Logan 200 a while ago, I noticed an uneven wear pattern on the front
gib where it contacts the bottom of the way. When I got around to looking at it
more carefully, I measured the spacers that are bolted between the gib and the carriage and discovered
they weren't the same length, with a difference of about .016". I checked my Logan parts list, which
showed they were the same p/n. A follow up email with Scott Logan confirmed that they should be the
same. So, I assumed that the difference in length was the problem, and shortened the longer spacer to
match the shorter part, which, because of the size of the notch milled in it's edge, appeared to be the
correct part. They are now the same length to less than .001".
I bolted the assembly back together, and found that spacer on the right (unworn) side is loose,
when the spacer on the worn side is snugged up. I was also able to slide a .006 feeler gauge into a
gap between the bed and the gib on the right hand side.
Here's a pic looking up, under the carriage at the gib as it's installed.
This pic shows the parts on the bench. The wear pattern can be seen on the left side of the gib. The right
side shows no wear at all. The amount of wear on the gib seems pretty small, though I
didn't have a good way to measure it. The gib has three points of contact: at the way, and under the spacers. All
three points were machined when the part was manufactured.
I decided to measure the gap between the two small contact points on the gib, and the carriage. The
pic below shows the gib clamped to the bed with spring clamps. The only tool I had to measure the gaps was
a spring caliper, which I carefully slid between the parts on each side, and then measured with a micrometer.
Not the best method, but I think I was consistent about how I did it. The gaps measured .514" on the left
side, and .523" on the right. (The spacers are .516" long.) So, it seems that the gib itself is the problem
and, I assume, was machined that way at the factory. It may be that someone put the longer spacer in
at some point without really solving the problem. So, what do I do? The only option I can think of is
to have the gib ground correctly, and then figure out what length spacers I would need. I think I'll
run this past Scott Logan next week, but I'm interested in what you guys think of this.
gib where it contacts the bottom of the way. When I got around to looking at it
more carefully, I measured the spacers that are bolted between the gib and the carriage and discovered
they weren't the same length, with a difference of about .016". I checked my Logan parts list, which
showed they were the same p/n. A follow up email with Scott Logan confirmed that they should be the
same. So, I assumed that the difference in length was the problem, and shortened the longer spacer to
match the shorter part, which, because of the size of the notch milled in it's edge, appeared to be the
correct part. They are now the same length to less than .001".
I bolted the assembly back together, and found that spacer on the right (unworn) side is loose,
when the spacer on the worn side is snugged up. I was also able to slide a .006 feeler gauge into a
gap between the bed and the gib on the right hand side.
Here's a pic looking up, under the carriage at the gib as it's installed.
This pic shows the parts on the bench. The wear pattern can be seen on the left side of the gib. The right
side shows no wear at all. The amount of wear on the gib seems pretty small, though I
didn't have a good way to measure it. The gib has three points of contact: at the way, and under the spacers. All
three points were machined when the part was manufactured.
I decided to measure the gap between the two small contact points on the gib, and the carriage. The
pic below shows the gib clamped to the bed with spring clamps. The only tool I had to measure the gaps was
a spring caliper, which I carefully slid between the parts on each side, and then measured with a micrometer.
Not the best method, but I think I was consistent about how I did it. The gaps measured .514" on the left
side, and .523" on the right. (The spacers are .516" long.) So, it seems that the gib itself is the problem
and, I assume, was machined that way at the factory. It may be that someone put the longer spacer in
at some point without really solving the problem. So, what do I do? The only option I can think of is
to have the gib ground correctly, and then figure out what length spacers I would need. I think I'll
run this past Scott Logan next week, but I'm interested in what you guys think of this.
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