Can turn pens but peppermills taking my life!!!

[siric]

Hi,

I am trying my hand at turning peppermills and have used two different processes but get the same (Bad) results!!

1.

Turn the entire blank and mark it with tenon, base, tenon, spigot, top, tenon. Turn down tenons, and part off.
Mount base and drill 1 5/8" and then 1 1/16 holes.
Mount top and turn down spigot to fit hole in base.
Drill 7mm hole through top.
Mount base on jam chuck, attach top and hold with live centre.
Turn entire mill to shape.

2.
Cut the square blank before-hand into base and top and then continue from step 2 above.


In both cases when I am done, the top has a cam like action when turned. It is perfect in one position, but as soon as it is turned, is goes out of alignment with the base.

Turns out that the holes at the top of the base are a little off-centre (have no idea why), so I mounted the base with that side on the jam chuck and cleaned up the outside. Turned it around, reattached top and brought up live centre and just turned the top to match the bottom, but the problem, although greatly reduced, still exists.

Would appreciate any assistance in getting to the bottom of this as I figure what what I have seen, it should not be this difficult!!

Thanks

Steve

 

[Charlie_W]

I am not a peppermill expert and not seeing exactly how you are chucking the individual parts or if there is something off about the Chuck, I will give this advise: after you have established your center tenon and recess on the two mating parts, put both parts together on the lathe, line up the grain, pull up the tail enter and finish turn the outside to final size/shape...with both pieces together.

If you are using the drilled hole as part of the tenon, that could be throwing you off as the drill may drift when drilling through the mill.

Sometimes a chuck that does not screw up tight against the shoulder on the headstock spindle can cause a chuck to wobble slightly. That is magnified as you move farther from the headstock.

Hope this helps.

 

[siric]

When I remount the base blank I use jam chuck to hold it from the inside and bring up a live center to the other end. I figure that this should give me a perfectly round base with the hole in the center.

I will try to use the Jimmie Gill method of doing the base and top separately measuring to see when I have gotten the same dimension.

Will try and report.

Thanks

 

[TellicoTurning]

Steve,
Not sure that my method will point you in the right direction or not... there are a number of vids on Youtube about doing mills and Ed Brown has a good tutorial... think it's in the library here, if not, might be on his exotic blanks site... check it out.

I only do the CrushGrind mills... I don't like the ones with the knurl knob on the top.. personal preference and I think the CG's allow for more creative designs...

I start with a 3x3 x ? what ever blank I need...
I generally allow about 2 1/2 inches +/- of length of the top,
First I turn the square blank round, then measure off what ever length I need for the top... I use 3 drill bits for my pepper mills... a 1 3/4" at the very bottom, then a 1 9/16 for the through hole and 9/16 for the top that holds the piece that turns the shaft...
The crush grinds are all ceramic grinders and have a 6", 10" or 18" pentagon shaft(depending on which you buy - I generally use the 10" and cut to fit).

Once I have the blank rounded, I measure off and mark that part that will be the top. I turn a tenon to hold the top in my chuck for when I drill the top.... and I cut another tenon just past the part so I can also hold the body in my chuck

I deviate from the directions slightly here since I don't use the drill bit that the directions calls for as the through hole....
Once I've decided the length for the top, I then allow another 3/8" to 1/2" of length for a tenon that will fit down into the through hole to keep the top from wobbling plus 1/8" for the parting tool. Once I've determined the top, I turn the tenon on the top down to size - just a hair under 1 9/16 so it will fit inside the through hold of the body and turn smoothly, then part the body part off the top.

I work with the blank with the part that will be the top towards the headstock.. again my preference, you can work in either direction. Once the body is parted away, I drill the hole for the top piece 9/16" about 1 1/2" deep into the top and then set the top aside for later.

I put the body in the chuck with the top part towards the headstock... then drill the 1 3/4 hold about 1/2-5/8 deep... just deep enough to clear the bottom part of the mechanism. I then switch to the 1 9/16 drill bit on an extension bit so I can drill straight through from the bottom to the top.... only if I have a body that will be longer than my drill bit extension do I try to drill to the center from either end... a number of people do swap ends and drill so that the holes meet in the middle... just my preference to not do so....

Once the through hole is finished, I have a jam chuck that fits into the 1 9/16 hole on the head stock and another that fits on a live center on the bottom end of the mill body.... with these in place, I turn up the speed on the lathe to about 1500 (again my preference of speed) and shape the body. Once that is shaped and sanded, I set it aside to do the top.

I have a set of pin jaws that will fit inside the 9/16 hold, (I usually move the tail stock up with a live center that will hold the blank on the pin jaws -- I don't always trust them to hold -- then shape the top to size and shape... you will want to make certain that the blank is flat and flush agains the chuck so that the top will turn true....otherwise you'll get that cam effect... if you part true this should be the rule and you'll not need true up.

This method is used for the crush/grind mills, but should work pretty much the same for the standard traditional mills as well... you'll just have the through hold for the shaft in the top/knurl nut that I don't.

My biggest problems with the standard traditional mills is I'm not always true with my dimensions, whereas the crush/grind allows me to worry about the design/shape of the mill and not the dimensions... I can cut the aluminium shaft to length to fit my mills.

Hope this helps... Pepper mills are a lot of fun.