Posted by Ron V on April 27, 2006 at 21:27:14:
In Reply to: Re: Problem with Fellows 36-6 posted by REA on April 25, 2006 at 22:52:29:
Once again thank you for your time. I’m sure you’ve got better things to do.
I can't understand why you think that cutter rub is happening when I have already mentioned in several of my posts that there is no evidence of cutter rub on the cutter itself. For the rather pronounced groves the cutter maybe leaving behind I would have thought that there would be obvious rub marks on the teeth of the cutter. I have seen evidence of cutter rub on cutters before and it's not easy to miss.
The marks being left behind are being produced consistently over the entire tooth gap profile. What you seem to be suggesting is that the marks would be being left behind on one flank. Is this correct?
To prove if we were getting cutter rub we stroked the ram down through a cut cycle, of a job that was going through the finishing cut, and held the ram at the lower T.D.C. point. The table at this stage had fully backed off. We then sprayed ink over the tooth gap area and then allowed the ram to continue on through to the upper T.D.C. We did this several times, each time removing the ink and then re-spraying the area. There seemed to be no evidence of cutter rub on the return stroke of the ram any where in the generated zone of the tooth gap.
I have already mentioned that we checked the float of the cutter ram, axially, radialy, and circularly in my first post. These checks were made with the ram in the lower T.D.C. position.
I have also already mentioned that we checked the four point bearing in my first post. We have a service manual for a 6A so have been using this as a crude way of finding out all the things we should be checking.
I feel like I’m repeating myself. Are you fully reading my posts? Are they too long? Would you like me to condense them for you so don’t have to wade through my ramblings on? Do you think I’m not explaining myself properly?
I asked a question in my last post and was wondering if could comment please. “Our Fellows 6A uses a spring loaded drive to the lower worm set. I guess it has as a sort of cushioning/dampening effect so as to isolate the “intermittent driving” of the indexing mechanism, due to the table relieving, from the rest of the machine. The 36-6 doesn’t seem to utilize this it seems to be a solid, positive drive with no dampening. Why would both machines be so different in their indexing drive trains and yet are so similar in the way they operate? Should the 36-6 have a dampening mechanism as the 6A?”
What is interesting in comparing the amount of wear between the two machines is that the 6A is in, I guess a pretty worn out state compared to the 36-6. And yet, we are doing some jobs in the 36 that we use to do in the 6A and the 6A never left these marks.
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