Table restoration - dowel screw woes

[Camo16]

Hi all,

New to the forum, so first off hi to everyone!

I'm almost finished on the restoration of a Hans Olsen/Frem Rolje table and have come across an unexpected hitch - I need a dowel screw that's 9mm wide, the original one was missing, and I can't find anything that's the right size out there

Wondering if anyone knows where I might be able to find one? Danish, so I'm guessing it's not a weird Imperial size?

Ta all!

 

[Cabinetman]

Hi, not at all sure really exactly what you’re trying to do, but if you can’t get one you can drill a hole and screw threaded bar into it, you may need to experiment a little to get the right tolerance fit and length of hole needed for it to grip sufficiently. Probably the nearest bar you will get is 10 mm – would that matter? I did this recently to hold a very heavy desk together and it worked a treat, two nuts on the threaded bar tightened against each other to get the bar into the hole. Ian
Edit, manners Ian, welcome to the forum.

 

[Phil Pascoe]

If it's missing, the hole may well be stripped away. As ^^^ but the threaded rod, headless/bolt could be epoxied in making sure any dust is removed and the epoxy worked around the hole well.

 

[--Tom--]

What screws onto the threaded section? May be a case of get a 3/8 and see if it works.

 

[Camo16]

Hi all, thanks for your comments - I've tried and M8 and 3/8 (too small) and M10 (too wide). Here's what it's supposed to screw into:

Was thinking of using the 3/8 which is closest and wrapping something around it?

Cheers!

 

[TheUnicorn]

am I right in saying you are attaching a leg? so is it a hanger bolt, with machine thread one side and wood thread the other?

 

[--Tom--]

Finding a replacement to fit that threaded insert if it isn’t a standard thread is going to be difficult. May be a case of drill out the insert and then fit a new m10 one so you can use an m10 dowel screw

 

[Cabinetman]

Is that a threaded metal insert in the " whatever it is you’re screwing into "?
I’m sorry but I really do feel we are pi ddling in the dark here,
Tom just said something very sensible.

 

[TheUnicorn]

I wonder whether something like this could be used to adapt to a size below
https://www.amazon.co.uk/QWSX-threa...eywords=m8+to+m9+sleeve&qid=1607641861&sr=8-1

 

[TheUnicorn]

never tried this, but I'm wondering whether you could wind a piece of solder into the tread of an m8 bolt, heat carefully, then screw into your m9 socket.

 

[OldWood]

My feeling looking at that thread that it is too course for a metric of that diameter. Have you got someone you know who has a digital caliper and thread guages such that the pitch, or threads per inch, can be found and hence from tables work out what thread it is. You are looking for a small metal working shop or a metal working enthusiastic amateur. I'm an amateur who inherited the guages from his Dad, and am unfortunately no where near Liverpool.

+1 to Tom as unless it it is UNC or something relatively common, even getting the thread details may not get you any further forward.

 

[Phil Pascoe]

Get a piece of 3/8th threaded rod, degrease it and the insert and clean the dirt out of hole in the leg (ensuring the hole will accept the non tapered rod). Fill both sides with epoxy and devise a way of holding it in place while the epoxy sets.
It's a table - it's not exactly a stressed connection.

 

[Camo16]

Hi all, thanks so much for your replies and great ideas. Apologies, as a newbie, for totally failing to provide the full context. Here's the whole back of the Roundette table. Three dowel screws are ok, the fourth is missing:

Metal screw inserts countersunk into the four leg holes.

Some really useful ideas, thanks again!

 

[pe2dave]

I wonder whether something like this could be used to adapt to a size below
https://www.amazon.co.uk/QWSX-threa...eywords=m8+to+m9+sleeve&qid=1607641861&sr=8-1

If they take it down ?? one mm? then it sounds perfect - use an M8 if that's strong enough.

 

[Phil Pascoe]

Not if the insert isn't metric. It would need to start off at 10mm to reduce it to 8mm, anyway.

 

[pe2dave]

Never used them Phil, I guess one mm is asking a bit much.
Do they cut a thread when being inserted please?
Thinking drill out to 8.5, then insert one?

 

[Phil Pascoe]

No, they screw in to an existing thread (often a damaged one).
I used one on my Jacob's chuck on my lathe. The threaded morse taper was 10mm, but I couldn't get a 10mm rod through the tailstock so had to use an 8mm one. They have an end bent across the diameter at the end which the insertion tool (screwdriver in my case) fits, which breaks off when the helicoil is in place. You can see it in the picture.
I guaranteed that never again will I need one - I bought a set.

 

[Camo16]

That looks really interesting - so I could just insert an M9 to M8 and then use an M8 dowel screw? That sounds like a fantastic option!

 

[Phil Pascoe]

10mm to 8mm, yes. 9mm to 8mm, no - there wouldn't be enough material between the two.

You could of course tap it to 10mm then reduce it to 8mm. It might be rough enough going metric from imperial, but it would be OK for your purpose. Make sure if you buy them you get the correct size - I bough some too small as I was going by the internal size and they go by the external.

Incidentally - if anyone knows more than I do, feel free to correct me.

 

[J-G]

Incidentally - if anyone knows more than I do, feel free to correct me.

You're pretty much correct Phil but the devil is in the detail.
Helicoil threads are not what you would normally consider a 'standard' thread form ... ie. the form isn't Whit. UNC or ISO ... as far as I can recall it is a 60º form, but of course it is a larger diameter so you can't just use a larger 'standard' tap to prepare the hole, you need proper 'Helicoil' Taps.

The original purpose of the Helicoil system was is to provide a better quality thread in Aluminium castings (engines) rather than repairing damaged threads - though naturally they can also be used for that as long as you first drill out to the 'Helicoil' root dia. and then re-tap the hole with the appropriate 'Helicoil' Tap.

It is quite some years since I had any real dealings with taps/dies/threading though it used to be my 'bread & butter' and time does take it's toll but the basics don't leave the memory