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| Modifying a Grizzly 9 X 19 (G4000) |
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| bogstandard:
Bernd, Grinding on a lathe is one of those controversial subjects where people have a lot of myths, phobias and conjecture. Passed along by old wives tales and people with nothing better to do. I personally think tales are spread because the people haven't had the know how or courage to try it for themselves, and so come up with all sorts of arguments for not doing it. Once you get into it, you will realise it is just another, although a slightly different machining technique, that once you have learned how to do it correctly, you will come back to doing time and again. I have been doing toolpost grinding as long as I have been machining, and I have yet to see a machine with any of the symptoms it is supposed to create that weren't caused by natural wear and tear on a well used machine. If you take the time to catch the majority of the dust, do a good clean down afterwards and keep your machine well lubricated, I will guarantee your bed won't fall in half overnight as some people seem to think will happen. It is no more dangerous to your machine than hard skin dust off cast iron or turning any glass filled plastics, which in my mind will cause a lot more damage than grinding dust. John |
| Bernd:
John, Back when I was working for the company they had many style grinding machines. So I've seen my share of different kinds of grinding form spindle noses to tapered bores. From standard cylidrical grinders to flat material grinders. The one thing I've never seen done in home work shop is when it comes to grinding is using a vacunm system. Although a bit dangerous of you suck in a lite spark since it'll set the rest of the swarf on fire. I've got some ideas furmenting in the back of my mind. I hope to try it out on this project. And of course the old cover all the ways trick is helpful to. I hope to see some progress on this project in the next few weeks. But first I need to reread your thread on Darren's lathe. I don't think I'll post a blow by blow buld since you've already done that. Think I'll just highlight perhaps what I needed to do different to make things work. I'll reference my writing back to that thread. Bernd |
| Darren:
Why don't grinding machines fail early if it's a problem? You may reply that the ways are covered, but have you ever notice where grinding dust gets to in the workshop? Everywhere, like sand on a beach.... |
| Bernd:
I was going to get started again with the Grizzly lathe project I had started back in September. I was going to start making the gibs for the carriage. But after close inspection on the bottom of the carriage, especially were the surfaces rub on the ways, I need to make a decision as to weather I should leave it as is or try to clean up the bad machining job that was done on this part. First an over view of the whole bottom of the carriage. The V groove that is to the left is the front on the carriage. The flat surface is toward the back. Notice how rough the flat part is and the shiny marks were the carriage rides on the ways of the lathe. You'll also notice two dark lines on either side of the V groove in the lower left of the picture. These are the contact points between the carriage and the ways. Here are two close ups of the flat way on the carriage. The first is of the whole length. The second is a close up of just one section showing the bright line of wear and the circular lines of the cutter. The last picture is of the V way showing the shiny area which is in contact with the V of the way on the bed. Notice how uneven the wear is and the lousy finish on a surface that rubs on the V of the bed? Now my dilemma is, should I leave the bottom of the ways alone or should I try and machine them to some form of smoothness. I haven't checked to see if the V way is a true 90 degree angle. The worst I can do is totally screw it up and I'll have to throw the carriage away. I can leave it alone, or I could get lucky and do a good job of fixing it. I look to the membership for suggestions. Bog's what do you think. Can it be saved or should I use it as is? Bernd |
| andyf:
Bernd, you might find a bit of help and encouragement here: http://www.fignoggle.com/machines/7x12lathe/kahale-martinapmachine-7x12/lathe1.htm which is a write-up (never finished) by Marty Nissen on how he sorted out all the sliding surfaces on a 7x12. Some of the pix are a bit mixed up with the text, but you will get the general idea. Jose Meneses in Portugal picked up the baton and ran with it: http://www.toolsandmods.com/saddle.html In each case, hours of hand work seem to be involved, to keep you warm during the long winter months. Andy |
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