Jeddly Posted March 18, 2012 Share Posted March 18, 2012 Hi, after doing some research, I decided to just build a KMG clone. The thing is closing on the backstretch, and I am having an issue with my tooling arm. I have used a wilton square wheel grinder before, and really like the interchangeability of tool rests and wheels/platens. So, my arm is drilled and tapped at the end, a half inch hole for tools/wheels, and I slit the bar with a portaband. My problem is that the pinch bolt will not lock the half inch bolt I am goint to use for wheels and such. After this failure, I decided to widen the gap with a cutoff wheel on my 4.5" grinder. Still no pinch. Any idears? Edited for pics cause everyone loves em. Quote Link to comment Share on other sites More sharing options...
John B Posted March 18, 2012 Share Posted March 18, 2012 Think about extending the slot beyond the spindle slightly as this may give more movement when you tighten the clamp screw, another alternative, clamp bolt fits direct onto spindle, (use a soft pellet between bolt end and spindle to help stop marring, or a flat on the spindle) Quote Link to comment Share on other sites More sharing options...
Jeddly Posted March 18, 2012 Author Share Posted March 18, 2012 Thanks John. I had not thought of extending the slit past the axle hole. It makes sense. I don't really gather what the soft pellet comment was intending though. Quote Link to comment Share on other sites More sharing options...
bigfootnampa Posted March 18, 2012 Share Posted March 18, 2012 Also I assume that you have a slip fit on the top half of the bolt hole? Because if that were threaded top and bottom the bolt wouldn't pull the top part down when tightened. Quote Link to comment Share on other sites More sharing options...
r smith Posted March 18, 2012 Share Posted March 18, 2012 Try using a piece of cold roll bar instead of the bolt. I would bet your hole is oversize and bolts are undersize so round bar may take up the slop. Quote Link to comment Share on other sites More sharing options...
Larry H Posted March 18, 2012 Share Posted March 18, 2012 If cutting the slot further doesn't do it, cut it far enough to drill another hole and separate the top half completely, using two bolts Quote Link to comment Share on other sites More sharing options...
Jeddly Posted March 18, 2012 Author Share Posted March 18, 2012 The top portion of the pinch bolt hole is drilled oversize, compared to the threads on the lower portion. I'll try the round bar deal this evening. Thanks for the input fellas!! Edit: Would the arm being 1080 have anything to do with it? Quote Link to comment Share on other sites More sharing options...
bigfootnampa Posted March 18, 2012 Share Posted March 18, 2012 1080 has some bearing as it will be stiffer steel but I think that you'll get a good pinch if you extend that slot another inch. Quote Link to comment Share on other sites More sharing options...
r smith Posted March 18, 2012 Share Posted March 18, 2012 How much oversize did you drill your hole? The bigger it is the more egg shaped it will be when clamping on a smaller shaft, depends on the relation between shaft and hole.... ;) Quote Link to comment Share on other sites More sharing options...
John B Posted March 19, 2012 Share Posted March 19, 2012 Thanks John. I had not thought of extending the slit past the axle hole. It makes sense. I don't really gather what the soft pellet comment was intending though. Soft pellet would stop the end of the securing bolt from marring the shaft it is clamping, so it will still slide easily in the housing. If you lock a bolt up onto the shaft it usually marks it, by using the pellet/pad it damages that instead of the shaft Quote Link to comment Share on other sites More sharing options...
Jeddly Posted March 19, 2012 Author Share Posted March 19, 2012 Ah, like a sacrificial sleeve of sorts. I getcha. The hole was driled with a 1/2" drill bit, and I forgot about the oversize business of bolts. I put a piece of 1/2" bar stock in it and seems to pinch better. After that I cut the slit past the hole another 3/4". Seemed to do the trick. Thanks for all the advice guys. I appreciate it alot. Quote Link to comment Share on other sites More sharing options...
r smith Posted March 19, 2012 Share Posted March 19, 2012 Great, glad it worked :D Quote Link to comment Share on other sites More sharing options...
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