dwentz
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- Dec 20, 2007
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I wanted to add a cam lock to the tail stock on my 7x10 mini lathe. There are many write ups on the net for this mod, LittleMachineshop.com even sells a conversion kit, but I wanted to build my own, and there is always room for improvement.
I did not work from plans, but had an idea of the improvements I wanted based on what other people had already done, and what supplies I had on hand. I am very happy with the results.
The first order of business was to mill the tailstock casting to accept the cam lock. As the far side of the casting is angled I milled the recess in the casting to accept a bushing for the handle to rotate on. This side of the casting was also square with the bottom so when I put it in the vise I indicated off of the top to get it close. The hole was centered and drilled while I had the casting set up in the vise. I also squared up the bottom of the casting for the cam lock housing body to rest on. No measurements were taken other than centering the hole. The hole is a little over 3/4 and was sized based on the material I had on hand for the bushing.
The resulting Hole on the other side. The small hole in the lower left was added later. It is for a stop to keep the cam lock lever from resting on the lathe bed
Here are the machined parts of the cam lock above, and a description of the parts below.
Handle:
This was turned from aluminum I had on hand. One side is drilled out 5/8 to match the cam.
The handle is 1/4 inch drill rod threaded 1/4 20 on each end. I cheated on the ball, I had it on hand.
Cam Housing:
The square cam housing has a 5/8's inch hole drilled clean trough that is centered to match the hole drilled in the tail stock casting. I did not take a photo of this setup, but when I made the round bushing to fit the tailstock I drilled a 1/4 inch hole in it first. Removed it from the lathe and installed it in the casting. This allowed me to center punch the cam housing. The block was then put in the mill and the hole was opened up to 5/8's to match the cam.
The larger hole in the cam housing is 7/8's and the cam piston which is 3/4 with a 5/8's inch hole drilled through for the cam to ride on.
Cam Piston:
The cam piston is 3/4 inch with a 5/8 inch hole drilled through. This allows the cam to be slipped through. The smaller section of the cam rides on the top of this hole to lock down the tail stock. The bottom the cam piston is drilled and threaded 5/16-18 to accept the bolt
Tail Stock Bushing:
The tail stock bushing fits into the hole drilled in the tailstock and supports the cam, as well as serving as a spacer for the cam housing.
Turn to match the hole in the tailstock, and make it a little longer so the handle will not rub on the tailstock casting. I faced the larger end to pad out the space from the inside of the casting to the cam housing.
Cam:
The cam is 5/8's with the cam section turned by putting a small 1/8 inch pad of aluminum between it and one of the jaws in the 3 jaw chuck. The cam was then turned. Again just winging it, nothing here is critical. Be sure to to make it wide enough for the cam piston to fit, but not too wide as to not allow the larger section to bit nicely in the cam housing. One end of the cam will have the handle attached, the other I cut a small grove and added a snap ring to hold it in place. The cam in the photo is actual pictured backwards to how it fits in the assembly. I did not notice it until after the photo was taken.
Tailstock Nut:
The tail stock nut was drilled to 5/16 clearance for the bolt that screws into the cam piston. I had to counter sink it a bit to allow the head of the bolt to clear the lathe bed casting. All corners are were rounded slightly to allow it to slide smoothly when installed on the lathe.
Stop Pin:
The stop pin is 3./16 drill rod threaded 10-32 on one end, and has s slot cut in the other for a flat blade screw driver. It fits on the tailstock casting to keep the handle and ball from laying on the bed of the lathe.
Spring:
The spring keeps the tailstock nut away from the lathe bed when the cam is not engaged.
I did not work from plans, but had an idea of the improvements I wanted based on what other people had already done, and what supplies I had on hand. I am very happy with the results.
The first order of business was to mill the tailstock casting to accept the cam lock. As the far side of the casting is angled I milled the recess in the casting to accept a bushing for the handle to rotate on. This side of the casting was also square with the bottom so when I put it in the vise I indicated off of the top to get it close. The hole was centered and drilled while I had the casting set up in the vise. I also squared up the bottom of the casting for the cam lock housing body to rest on. No measurements were taken other than centering the hole. The hole is a little over 3/4 and was sized based on the material I had on hand for the bushing.
The resulting Hole on the other side. The small hole in the lower left was added later. It is for a stop to keep the cam lock lever from resting on the lathe bed
Here are the machined parts of the cam lock above, and a description of the parts below.
Handle:
This was turned from aluminum I had on hand. One side is drilled out 5/8 to match the cam.
The handle is 1/4 inch drill rod threaded 1/4 20 on each end. I cheated on the ball, I had it on hand.
Cam Housing:
The square cam housing has a 5/8's inch hole drilled clean trough that is centered to match the hole drilled in the tail stock casting. I did not take a photo of this setup, but when I made the round bushing to fit the tailstock I drilled a 1/4 inch hole in it first. Removed it from the lathe and installed it in the casting. This allowed me to center punch the cam housing. The block was then put in the mill and the hole was opened up to 5/8's to match the cam.
The larger hole in the cam housing is 7/8's and the cam piston which is 3/4 with a 5/8's inch hole drilled through for the cam to ride on.
Cam Piston:
The cam piston is 3/4 inch with a 5/8 inch hole drilled through. This allows the cam to be slipped through. The smaller section of the cam rides on the top of this hole to lock down the tail stock. The bottom the cam piston is drilled and threaded 5/16-18 to accept the bolt
Tail Stock Bushing:
The tail stock bushing fits into the hole drilled in the tailstock and supports the cam, as well as serving as a spacer for the cam housing.
Turn to match the hole in the tailstock, and make it a little longer so the handle will not rub on the tailstock casting. I faced the larger end to pad out the space from the inside of the casting to the cam housing.
Cam:
The cam is 5/8's with the cam section turned by putting a small 1/8 inch pad of aluminum between it and one of the jaws in the 3 jaw chuck. The cam was then turned. Again just winging it, nothing here is critical. Be sure to to make it wide enough for the cam piston to fit, but not too wide as to not allow the larger section to bit nicely in the cam housing. One end of the cam will have the handle attached, the other I cut a small grove and added a snap ring to hold it in place. The cam in the photo is actual pictured backwards to how it fits in the assembly. I did not notice it until after the photo was taken.
Tailstock Nut:
The tail stock nut was drilled to 5/16 clearance for the bolt that screws into the cam piston. I had to counter sink it a bit to allow the head of the bolt to clear the lathe bed casting. All corners are were rounded slightly to allow it to slide smoothly when installed on the lathe.
Stop Pin:
The stop pin is 3./16 drill rod threaded 10-32 on one end, and has s slot cut in the other for a flat blade screw driver. It fits on the tailstock casting to keep the handle and ball from laying on the bed of the lathe.
Spring:
The spring keeps the tailstock nut away from the lathe bed when the cam is not engaged.
