# I need help!!! top burr thread has jammed tight



## paul whu (Sep 25, 2014)

I was just casually cleaning out my grinder when disaster struck. Took it apart in the usual way, worm drive off and unscrewed it, gave it a good clean and proceeded to reassemble it. For the first part of it's journey the top section was easily winding into place. With about a centimetre to go it began to stiffen up a bit. I popped the worm drive adjuster back on thinking I would finish the job using that. Schoolboy error. it is now wedged tight.

I tried plugging it in hoping that I could free it up under it's own steam. It tries but can't spin. I'm mortified to say the least.

The machine in question is a Macap MXD 75mm on demand.

I am considering squirting a tiny drop of lube onto the threads but think I need advice before I destroy the grinder altogether.

Any ideas gratefully recieved


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## Yes Row (Jan 23, 2013)

@El carajillo is the man who seems a good bet, for my money

My advice, is try a bigger hammer?


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## paul whu (Sep 25, 2014)

NOOOOOOOOO!!!! Not the hammer.....not yet anyway!! Thanks for the tip though!


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## paul whu (Sep 25, 2014)

I have now separated the top burr set. Wasn't easy but have got them apart. However i still have an issue in that I can't get it to screw down beyond the same point as it got wedged before. There are 2 tiny dents in the thread which are obviously causing the problem. The damage is to the female section as it were.

I can still run the tip of an electrical screwdriver all around the thread at the point of the damage. The snug fit of the male section thread will not budge past this point however. Shall i try and somehow file this down with a sharp implement (the metal is obviously softish), Try and buy a new threaded insert or what???? I am sure others on here will have had this problem before. Any thoughts would be welcome.


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## GlennV (Mar 29, 2013)

You'll need a thread file, they can remove the excess material without any chance of making things worse. Is it the internal or external thread that's damaged? The ones that do internal threads as well as external are a bit more expensive.


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## h1udd (Sep 1, 2015)

If you are resigned to buying a new thread then you have nothing to loose by trying a repair ... Have you a tap and die set ? ... The blades on taps are good at mending massive threads with a little dexterity


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## paul whu (Sep 25, 2014)

Thanks Glennv. I'll check out Screwfix straight away.


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## GlennV (Mar 29, 2013)

It's probably a bit too specialist for screwfix I'm afraid. This is the one I got (for a similar problem originally!) - it's external threads only. They are a very clever piece of kit, and I've used it many times since.

http://www.ebay.co.uk/itm/-/171001963370?ssPageName=ADME:L:OU:GB:3160


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## paul whu (Sep 25, 2014)

Definitely worth a go, Thanks


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## El carajillo (Mar 16, 2013)

With the end of a small triangular file , you may be able to scrape off the damaged part of the thread as the metal is relatively soft. As it is the female part of the thread I do not think the "thread file" will work as they are for external threads Ie the male part.


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## NickdeBug (Jan 18, 2015)

I had the same problem with the MXD when I first got it.

Seems to be an easy one to cross theead









On Dave (coffeechap)'s advice i cleaned out the threads and then added it bit of vaseline. It was actually Aloe Vera lip balm with vaseline but it was the only vaguely similar stuff in the house.

Anyway, rethreaded with great care and not had a problem since.

I never take off the burrs anymore. To clean i just loosen the accessible matter from the burr with a toothpick and then stick the vacuum cleaner nozzle on it (again, based on Dave's advice).

Maybe I was lucky in that there was no obvious thread damage, but a bit of vaseline is worth a try.


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## GlennV (Mar 29, 2013)

Ones like this do internal threads too (its the part on the end). If this won't go deep enough then I'd use a tap, as h1udd suggested, or take it to a machine shop.

http://www.ebay.co.uk/itm/BGS-Tools-Thread-File-For-Internal-And-External-Threads-0-80-3-00-Metric-1922-/230907998858?hash=item35c330728a:g:dFUAAOSwEeFVDRRg

I wouldn't use vaseline, personally, if you're going to carry on removing the burr regularly. It attracts the coffee dust and turns into grinding paste, which wouldn't be good for the threads long term.


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## DavecUK (Aug 6, 2013)

I must admit this problem is one reason I like grinders such as the Ceado and Eureka range.


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## mremanxx (Dec 30, 2014)

What is the thread size Paul? I have taps, dies and thread chasers


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## Rhys (Dec 21, 2014)

Whatever method, be mindful to thoroughly vacuum the grind chamber as it'll have metal swarf particles in it afterwards. If it's only a small burr, try folding a bit of wet&dry paper in half and running that in the thread. Are the threads brass?


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## Rhys (Dec 21, 2014)

mremanxx said:


> What is the thread size Paul? I have taps, dies and thread chasers


Proably sounds the best bet


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## paul whu (Sep 25, 2014)

I am really grateful for all the help and advice offered. I have now fully sorted the issue using a kind of blend of the various ideas.

A tap and die set and a thread file were unavailable from toolstation and screwfix. I ended up with an engineers scribe and ran it back and forth along the thread in the dent for ages and ages. I then cleaned the threads with my Girlfriends toothbrush, added a tiny drop of Crisp and Dry and Hey Presto!!!!!!

I wasted about 150 g of beans dialling back in but I'm all set for my morning vice.

Once again a massive thanks for your advice


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## NickdeBug (Jan 18, 2015)

Glad to hear that it is sorted Paul.

It is an excellent grinder. Highly unlikely that the burrs will need changing based on standard domestic use, so I really recommend following Dave's advice and just clean using a vacuum cleaner tube from the top.


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## paul whu (Sep 25, 2014)

NickdeBug said:


> Glad to hear that it is sorted Paul.
> 
> It is an excellent grinder. Highly unlikely that the burrs will need changing based on standard domestic use, so I really recommend following Dave's advice and just clean using a vacuum cleaner tube from the top.


Maybe an idea to try Grindz. I have heard that they are effective. Funnily enough there wasn't a lot of retained grounds in the chamber and the burrs were looking shiny and sharp. There was a little gunk wedged beneath the lower burrs but hardly anything. I don't really know why I decided to strip it down today to be honest. Probably to get me out of going Christmas shopping.


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