Trouble with crush grind pepper mill mechanism

[Chuck Jones]

What kind of glue should I use to hold the PKCrushgrind insert in the cap? I used epoxy only to find out it will not adhere to the plastic.

I just finished the best looking pepper mill I've ever built and intended to donate it to a Relay for Life auction tomorrow night. It worked fine until I had the bright idea of putting peppercorns in it. Forget it! The first slightly hard peppercorn caused the cap to spin on the mechanism. This is the first time I've used the crush grind mechanism and unless I find out I did something stupid, it will be the last.

Any suggestions will be appreciated.

[robert hainstock]

I'm working on one of those now. I'll skip the epoxy thanks for the warning. I may try gorilla. That is some slippery stuff. :eek::eek::eek:
Bob

[Tim A. Mitchell]

I have not used one, but would have thought that epoxy woul have held well. Robert, just be carefull of the expansion on the Gorilla glue.

What is the top of the mechanism made of?

[Chuck Jones]

I have not used one, but would have thought that epoxy woul have held well. Robert, just be carefull of the expansion on the Gorilla glue.

What is the top of the mechanism made of?

"Plastic" I don't know what kind, but apparently one that epoxy doesn't work on. I haven't used much epoxy. I just followed the instructions. It list several types of plastic that it will not work on.

[Brian Brown]

When I used a crush grind mech., I assumed that I would have the same problem, and because I was short of time, I used a file to scratch up the top of the aluminum shaft where it would sit inside the cap. I then inserted the shaft into the plastic cap, and used it like a file or sandpaper to rough up the interior of the plastic cap. Then some 60 minute epoxy, and it seems to have held well. Maybe someone else has a better idea. I will keep watching this thread.

[Chuck Jones]

Brian,
The shaft is not turning inside the plastic insert; the insert is turning inside the wood (black walnut) cap. The epoxy held to the wood, but peeled right off the plastic insert. I may not be understanding what you meant... and my terminology is not very specific because I don't know for sure what they call these darned parts.

I'm thinking maybe I should have crammed a lot more epoxy in the gaps on the plastic cap and maybe let it set more than the couple hours that I let this one set. In any case I'm going to try that tonight while I'm making another mill with the old fashioned deluxe mechanism.

[M Toupin]

Rough the plastic up with 100 grit or so. Epoxy, like most glues, are a mechanical bond and need something to bite into.

I'd not recommend gluing the aluminum shaft to the cap unless you fill it with pepper corns first and you intend for it to be a single use mill...

Mike

[Lonnie Cook]

Since I've only made one Crushgrind grinder (salt), I'm no expert ...

I used the model without a shaft. The outer shell had vertical ribs. The inner part had three fingers. I drilled the body that held the mechanism the same diam as the outer shell, then filed valleys for the ribs. I carved dents in the other part for the fingers to pop into. Epoxy held the Crushgrind secure, but the mechanical connection of the ribs and fingers kept it from turning in the body, or popping out.

- Lonnie

[Rasmus Petersen]

Im looking forward to the solution, but i think that you should have let it cure longer.. i would say 24 hours before straining the bond. there are from i can se on the page at the danish makers several kinds of mecanisme, for insertion into wood plastic and metal.

[Cary Swoveland]

Chuck, here are some installation instructions prepared by Woodcraft:

http://www2.woodcraft.com/PDF/77c14.pdf

Hope this might help.

Cary

[Ken George]

I have made several of these and use CA on top and bottom. Never had a problem. Every one who has received one of these loves them. Don't give up!

[Charlie Schultz]

I've also made several and used epoxy (the 60 minute and 5 minute stuff) with no problems.

[Greg Savage]

I'd not recommend gluing the aluminum shaft to the cap unless you fill it with pepper corns first and you intend for it to be a single use mill...

Mike

If need be, CrushGrind mechanisms can be filled from the bottom.

Use epoxy after roughing up your plastic. It will work quite well. Don't use CA if it can be avoided....It can be very brittle and fail when grinding coarse sea salts.....Certain salts can place some incredible torque on the mechanism.

Gorilla glue will expand to a point where problems will arise due to the glue filling in around the top of the upper insert. This makes it difficult to insert the shaft.

[Chuck Jones]

I think the suggestions to rough up the plastic make sense. Unfortunately I didn't see that or think about it until I had already gobbed a bunch more glue onto the top insert for another try. I'm letting it set longer this time before I try to grind pepper with it.

Cary: My crush grind mechanism came from Packard. I believe it's different from the one referenced to in the Woodcraft instructions. I think I saw a brand name of "PKCrushGrind" on it.

In the meantime I made another mill last night for the auction using the older type mechanism.

Right after I started trying woodturning I turned 10-12 pepper mills for Christmas presents and it went like a breeze. My wife asked me to make a couple things for the Relay For Life auction and I thought a pepper mill will be quick and easy for one of the things.

First one I turned out of willow oak and after I finished it I looked at it and the shape was coyote ugly.

Turned the second one using walnut and it turned out quite nice. Couple days later it had a crack in it.

The third one was from sycamore and the wood was just plain blah.

For the forth one I used black walnut and decided to experiment with the crush grind mechanism. Everyone absolutely loves the look of this one. We also thought we liked the mechanism until I tried to grind some pepper.

For the fifth try I used black walnut and the older type mechanism. It turned out pretty decent and maybe someone we don't know will buy it before anything happens. I hope the glue holds on number four. If not I have a decent backup.

What I lack in skill I make up for in tenacity.

Thanks for all the suggestions and help.

[Chuck Jones]

As stated earlier, I reglued the mechanism into the cap with a "gob" of epoxy and let it cure for about 24 hours. It appears to be holding, but I was not confident enough to donate that mill to the RFL auction. It all turned out for the better; my wife likes it and wants to keep it anyway.

Not sure what I've learned from all this. Had lots of people try to help including here and at Packard Woodworks. I like the ceramic grinder and I like not having to put the shaft through the cap, but it all seems a little too imprecise to draw much conclusion. If I try another one I'll try a combination of the suggestions you folks made:

1. Ignore the instructions and don't remove the little vertical ribs.

2. If the mechanism is too tight with the ribs, file some groves inside the cap (and in the base if necessary).

3. Rough up the plastic and use a lot of epoxy on both the top and bottom mechanisms

4. Let the glue cure at least overnight.

5. Give it to someone who isn't likely to actually use it... just kidding!



(Black Walnut - 11" x 2 1/4")

[tommy smith garner]

I'm working on one of those now. I'll skip the epoxy thanks for the warning. I may try gorilla. That is some slippery stuff. :eek::eek::eek:
Bob

I'v made several using the crushgrind and epoxy. i used the clear kind that you push out from two barrel syringes and mix, made by loctite, never had the 1st problem with slippage...look carefully to see just where the wood will contact the mechanism when inserted and spread the glue fairly thick making sure to not contact the area where the shaft enters the mechanism. give it a full 24 hrs before using. http://www.woodturnerscatalog.com/woodturners/Images/pdfs/crush_grinder.pdf also cut the shaft so it will go all the way thru the top piece just barely when you place the top on, if it just barely enters the top piece the there is not enough friction to hold it securely when you turn hard...you will have to give a little push to get it thru, when you pick up the mill by the top only the cap should remain in place, if it sips off you are not deep enough.

[tommy smith garner]

I agree that it seems a bit much also, may just go back to the old style myself.

[Greg Just]

I have made lots of these and always used Loctite 2 part epoxy and never had a problem. The 60 minute version has better holding power than the 5 minute. I would not give up. Also, Make sure you are drilling the recommend size holes otherwise this can contribute to a failure.

[Mike Golka]

I have made over 30 of these and used 5 minute epoxy on all of them with no issues. Some are over 5 years old and see daily use. As Greg stated the size of the hole is very important, the plastic insert should fit snugly into the hole.

[Chuck Jones]

I find it amazing that this thread pops up again after 4 years. Gotta watch what I say.:)

Since then I have completely sworn off the crush grinds because of all the problems I've had. However I have seen several interesting suggestions recently that might work... including Tommy's suggestion of making sure the stem pushes through the top piece far enough to hold. I just went to the kitchen to look at a pepper (#4 in my earlier post) mill and a salt mill. The pepper mill is okay. The salt mill is a disaster. Every time someone picks it up by the top the bottom falls into the soup or whatever. Guess what? The stem is not as long as the one on the pepper mill.

There is an article on this issue in Woodturning Design a couple issues back. Sorry I can't put my hands on the magazine at the moment. It's by a fellow from the UK and quite extensive. Worth reading if anyone is still interested in using a crush grind and still having problems.

[Bernie Weishapl]

Funny this came up again after 4 yrs. Watch what you say as it could come back to haunt you.:D:rolleyes: I will say like Mike G. I have made 30 of the crush grinds pairs and have never had a problem with them using epoxy. My sister has my first set of salt and pepper mills which are 6 yrs old. I just used them sunday as we had dinner with them. Solid as the day I made them. I think Greg hit the nail when he said accurate holes are the key.

[John King]

When properly installed, the CrushGrind@ mechanism requires no epoxy or similar adhesive. Here’s the deal.

Most, but not all, instructions for making CrushGrind@ mills provided by US suppliers specify 1) a 1 9/16” diameter hole in the mill body for the grinding mechanism, 2) removal of the spring clips from the grinding mechanism and 3) use of epoxy (or similar) to secure the grinding mechanism in the mill body. These same instructions specify 1) a 15/16” diameter hole in the mill cap for the stopper, 2) removal of the spring clips from the stopper and 3) use of epoxy (or similar) to secure the stopper in the mill cap. One can make a very nice pepper/salt/spice mill using these instructions. But there is a better way! It’s the no epoxy required way.

The manufacturer’s recommendation for the diameter of the hole in the mill body for the CrushGrind@ mechanism is 38mm (1.496”). I am good with calling that 1½” (1.500”). The manufacturer’s recommendation for the diameter of the hole in the mill cap for the stopper is 22mm (0.866”). I am good with calling that 7/8” (0.875”).

No epoxy (or similar) is required to secure the grinding mechanism in the mill body and the stopper in the mill cap if 1) the CrushGrind@ manufacture’s recommendations for mill body and mill cap hole diameters are used and 2) a groove is cut in the mill body and the mill cap to accept the spring clips on the grinding mechanism and stopper.

Sorby makes a groove cutting tool for CrushGrind@ mechanisms. The part number is 895CGH. This tool can be purchased from Brian Fitzsimmons at Constable Woodcrafts (www.constablewoodcrafts.co.uk (http://www.constablewoodcrafts.co.uk/)). It’s a must have tool if one is going to install the CrushGrind@ mechanism in pepper/salt/spice mills using the spring clips and no epoxy.

With the grinding mechanism and stopper press fit into the mill body and cap, respectively, and the spring clips locked into the mill body and cap grooves, epoxy is not required for a secure fit.

An excellent set of instructions for making a pepper/salt/spice mill using the CrushGrind@ mechanism can be found in Turning Salt & Pepper Shakers and Mills by Chris West, “Drilling and Fitting a CrushGrind@ Mechanism,” p 132.

In my opinion, the CrushGrind@ mechanism is far superior to the stainless steel grinding mechanisms. It can be used to grind pepper, salt and spices. The grind can be adjusted from course to very fine. It’s made of non-corrosive ceramic. There is a 25 year guarantee on the ceramic parts inside the CrushGrind@ mechanism.

Give it a try. I think you will like it. – John

[Charles Bjorgen]

That's a very informative reply, John. I wish that tool was available here in the U.S. I like the Crush Grind mechanism and so far have cut off the clips and used epoxy. Would like to avoid those steps. Thanks.

[Chuck Jones]

John that is definitely a new approach. But there are two basic problems that I have experienced. The first is addressed by your post. The other is the problem with the cap slipping off the shaft. Tommy suggested that one needs to make sure the stem is left long enough to extend well through the cap. Have you had this problem? If so any thoughts?

[John King]

Chuck - The mill shaft must be long enough to extend through the stopper. See photo below. Make sure you drill the stopper hole in the mill cap deep enough to accept the mill shaft. I drill 7/8" diameter hole 3/4" deep for the stopper. Then I drill 1/2" diameter hole 3/4" for the top of the stopper and the mill shaft that extends beyond the top of the stopper. Total hole depth is 1 1/2". When the stopper grips the mill shaft in this manner, no problem with picking the mill up by the cap.
236414

[Gregory Heard]

I have not personally used it but Woodcraft sells a Crush grind groove cutting tool simliar to the Sorby tool. It is made by pinnacle. Do a search on "Pinnacle Cryogenic Pepper Mill Tool"

[Dale Coons]

Or, if you have a hollowing tool, make a short cutter--and set it perpendicular to the shaft. It will fit in the drilled hole, and make a groove just like the 'official' tools. I made one from a piece of scrap rod that I had. That also works and is free if you have the other stuff. For that matter, a sharpened hex key might also work. Figuring out how far up to make the groove is the challenge--too high, and you can always move it down. To low, and you're back to epoxy, which is why I think epoxy gets recommended in the first place.

[alan ball]

Try watching this youtube video and all will be explained

https://www.youtube.com/watch?v=XdPQ7sfZeeU

[Steve Schlumpf]

This thread is almost 5 years old! DO NOT start adding on suggestions for what Chuck can do to fix the problem!

[Chuck Ellis]

I find it amazing that this thread pops up again after 4 years. Gotta watch what I say.:)

Since then I have completely sworn off the crush grinds because of all the problems I've had. However I have seen several interesting suggestions recently that might work... including Tommy's suggestion of making sure the stem pushes through the top piece far enough to hold. I just went to the kitchen to look at a pepper (#4 in my earlier post) mill and a salt mill. The pepper mill is okay. The salt mill is a disaster. Every time someone picks it up by the top the bottom falls into the soup or whatever. Guess what? The stem is not as long as the one on the pepper mill.

There is an article on this issue in Woodturning Design a couple issues back. Sorry I can't put my hands on the magazine at the moment. It's by a fellow from the UK and quite extensive. Worth reading if anyone is still interested in using a crush grind and still having problems.

Chuck,
I'm going to make this thread pop-up again after another 4 years (+/-) .... I read your opening post (the thread popped up on another search I was doing about pepper mills.... I make the Crush/Grind peppermills almost exclusively ... I do make some of the little crank operated mills as well)... I've only had one mill in the last 10 years where the piece popped out of the head piece...and I had use CA to glue that in... Epoxy has never failed me..... I do one other thing that both PSI and Woodturners catalog don't mention.... when I get the top drilled for the drive unit, I cut a groove inside the head piece to take the little tabs on the drive piece... I still use the epoxy, but the tabs catch on the edge of the groove and won't allow the piece to come out. One of the tool makers, Sorby I think, makes a tool just for this purpose, but I have a recess tool that came with my thread chasers that I use... I have a couple of marks on the tool to indicate the depth I need to go to make the groove... the groove does need to have vertical/square sides.

I also cut a similar groove in the bottom of the mill to take the grinder's tabs...