View Full Version : 4 spur center
ralphtaff
03-25-2009, 11:25 AM
I have a problem with the 4 spur center staying on in the wood.it keeps spinning on the wood. this happens on all the wood i try. i hade a school wood shop teacher look at my center and he said it was ok, i made sure it was on real good. could i have that much wobble in the shaft of the markv that it is causing this?
greitz
03-25-2009, 11:33 AM
Maybe the wood you're using is so hard that the spurs can't dig in deep enough? Rick Davis showed us that for very hard woods, you might need to saw two perpendicular slots in the end of the blank to get the spurs deep enough.
Gary
Did you have a pilot hole for the point?
JPG40504
03-25-2009, 11:37 AM
Maybe the wood you're using is so hard that the spurs can't dig in deep enough? Rick Davis showed us that for very hard woods, you might need to saw two perpendicular slots in the end of the blank to get the spurs deep enough.
Gary
OR not 'driving' it in far enough. Cross sawing WILL help. Drilling a (small)pilot for the point MIGHT help. Are you putting enough pressure from the quill?
ralphtaff
03-25-2009, 09:12 PM
Who knows? i thought so but maybe not. i have done all of the above. a teacher at the school i work at has a shop smith and he does not have any trouble with his on the same type of wood. we both get it from the junk pile at the school. he is going to let me use his spur center and see if maybe i need a new one. i just did not want to buy a new one then still have the same problem. will let you all know what i find out.
Do the points of both centers line up?
charlese
03-25-2009, 11:10 PM
I have a problem with the 4 spur center staying on in the wood.it keeps spinning on the wood. this happens on all the wood i try. i hade a school wood shop teacher look at my center and he said it was ok, i made sure it was on real good. could i have that much wobble in the shaft of the markv that it is causing this?
Sorry Ralph, I haven't had this problem whenever I follow Shopsmith's written instructions. (I have occasionally tried to get away from these steps, but the center slips, as you describe and I have to go back to the basics.)
They say to first drill a 1/8" hole in the center of each end of the blank. The hole should be 1/4" deep. Second saw perpendicular slots that cross at the pilot hole. I will use either the bandsaw or a Japanese pull saw to make these slots. These slots should be about 1/8" deep and wide enough to accept the 4 spurs.
These instructions cannot be found in PTWFE, but in the Shopsmith Instruction Manual. (in the White plastic notebook)
I turn hardwoods, but if turning pine, spruce or Western red cedar, I would try to get by without the slots, but would drill the holes.
ralphtaff
03-26-2009, 10:05 AM
after reading all the posts at several different forums imayby my problem is the speed. To make a long story short, i have one speed to change speed i have to change pullys so with a 2 inch pully at the motor and a 4 inch pully at the shaft i get about 862 rpm that does good on the ring master and out of round bowls about 8 to 10 inch. so for a spindle i am probably to slow? what say you all.i can reverse the pullya and get 3450 rpm, wouyld that be better? or to fast?i have 1.75 pully,2inch,2.5inch,4inch and 6inchpully.