Suggestions for captive/caged nuts

[BladeRunner]

Hi All,

It's been a while since I've been here.

I've dusted off the woodworking gear as I have a few projects coming up - mostly due to the arrival of both a grandson and granddaughter.

However, I've also recently bought a telescope which is too big and heavy to manage by myself so I built a rough and ready dolly out of some cheap 70 x 35 pine. The casters are easily detachable as I want to remove them when I position the scope and lower it to the ground for stability.

So the last piece of the puzzle is to arrange for four "jacks" which will allow me to raise the dolly enough to remove the casters and then wind them out until it settles on the ground. The telescope weighs 40kg.

I was inspired by a very well designed and engineered steel example I saw online. This uses what looks like M10 or M12 bolts with nuts MIG welded to the underside of the steel sections to serve as the jacks. In fact they look rather like they came from g-clamps.

Since I can't weld nuts to timber, my first thought was to use threaded inserts. The biggest I can get locally are M6. I tested one of these and it seemed to lift around 13kg easily but M6 bolts just look a bit thin to my eye. I don't think t-nuts are the answer either.

Hopefully I've explained this adequately. I'd be grateful for any suggestions regarding a way to add some jacks to the dolly.

Paul.

[jmk89]

Elraco (https://elraco.com.au/index.php/insert-nuts-c-24_1111_3794) have 10mm (3/8") threaded inserts that might work for you.

[BladeRunner]

Thanks Jeremy,

They would certainly do the job. Freight charges make them a touch expensive but at least I know where to get some if all else fails.

Thanks for the link.

[jmk89]

Freight charges make them a touch expensive....

True.I find that I can always find some 'shop supplies'(e.g. glue,screws,hinges,etc)
Keeps the freight cost down per $ spent :U

[elanjacobs]

Check Häfele, I think they have up to M12

[BladeRunner]

Keeps the freight cost down per $ spent :U

Now that's an idea. The freight is a flat rate. Bound to be something else I can use.

[BladeRunner]

Check Häfele, I think they have up to M12

There seems to be a minimum quantity of 100. But they illustrate what makes it interesting to find these things. There are several names for the same object - insert nut, threaded insert and Hafele calls it a screw-in sleeve.

Thanks.

[Uncle Al]

If you go down the threaded insert route, use the flanged ones, they are much stronger than the plain ones which tend to split where the Allen key fits in.
Tee nuts are available in 3/8" from Bunnings etc, not sure if they are made in any larger threads.
Check the fastener supply companies around your area, or a furniture components supplier, or even a small furniture manufacturer who may sell you a small quantity if you ask nicely.
Do you really need to remove the castors?, wouldn't it be easier just to jack them up off the ground a millimetre or two with the jacking bolts.
At 40Kg, your telescope seems like a pretty serious bit of gear, is it a Mead brand?

Alan...

[Lappa]

http://www.thewoodworks.com.au/shop/hardware/knock-down-hardware/insert-threaded-brass-detail

Have both 8mm and 3/8"

[Glennet]

This company lists lots of items which would do the job, particularly the T nuts:Flexliner | Levelling Feet (http://levellingfeet.com.au/index.html)

[Bohdan]

Just fit regular hex nuts into the timber by drilling a short hole and chiselling out the hex shape. If the hex hole is slightly undersize you will have to force the nuts into the timber and it will hold quite well but if your not happy with the grip a touch of epoxy will make it permanent.

[BladeRunner]

If you go down the threaded insert route, use the flanged ones, they are much stronger than the plain ones which tend to split where the Allen key fits in.
Tee nuts are available in 3/8" from Bunnings etc, not sure if they are made in any larger threads.
Check the fastener supply companies around your area, or a furniture components supplier, or even a small furniture manufacturer who may sell you a small quantity if you ask nicely.
Do you really need to remove the castors?, wouldn't it be easier just to jack them up off the ground a millimetre or two with the jacking bolts.
At 40Kg, your telescope seems like a pretty serious bit of gear, is it a Mead brand?

Alan...

Hi Alan,
Yes, the M6 insert I tried is flanged.
I called the local specialty fastener shop yesterday and they normally stock them but are out of stock. He suggested a local furniture hardware supplier but I haven't found them yet.
Maybe I'll try the 3/8" T-nuts. There's not going to be a great deal of torque on them. No reason it needs to be metric.

I've already made the casters removable. But the metal version I saw online uses proper rubber wheels (which were out of budget for me) which he removes but then uses the jacks to level the scope. My scope has no particular need to be exactly level. I'll see how it feels when I get the jacks fitted - your suggestion may be reasonable.

The scope is a Skywatcher 12" collapsible dobsonian. I probably should have bought the 10" version (which I can carry around) and saved all the trouble but "Aperture is King" with newtonian telescopes. :)

Thanks for the suggestions.

[BladeRunner]

Knock Down Hardware : Insert, Threaded, Brass (http://www.thewoodworks.com.au/shop/hardware/knock-down-hardware/insert-threaded-brass-detail)

Have both 8mm and 3/8"

Thanks Lappa.

There's plenty of other bits and pieces to make the postage charges reasonable.

[BladeRunner]

This company lists lots of items which would do the job, particularly the T nuts:Flexliner | Levelling Feet (http://levellingfeet.com.au/index.html)

Thanks Glen,

Lost of interesting hardware there. The "weld-on" T-nuts look good.

[Boringgeoff]

Paul,
if it was me I'd cut four pieces of 50 or 40mm x 3 mm flat bar, bore a hole in the centre appropriate to the nuts you want to use, weld the nuts on then bore four screw holes in the flat to connect to the underside of the dolly. The centre hole should be bored slightly oversize, a short bolt that suits the nut holds it in place while you weld it. A wrap of paper round the bolt where it goes through the hole will ensure the nut is central.
Cheers,
Geoff.

[BladeRunner]

Just fit regular hex nuts into the timber by drilling a short hole and chiselling out the hex shape. If the hex hole is slightly undersize you will have to force the nuts into the timber and it will hold quite well but if your not happy with the grip a touch of epoxy will make it permanent.

Good suggestion, Bohdan. It's a bit more work but certainly avoids the need for any special hardware. My smallest chisel would still push me to a bigger size nut but that doesn't matter.

[BladeRunner]

Paul,
if it was me I'd cut four pieces of 50 or 40mm x 3 mm flat bar, bore a hole in the centre appropriate to the nuts you want to use, weld the nuts on then bore four screw holes in the flat to connect to the underside of the dolly. The centre hole should be bored slightly oversize, a short bolt that suits the nut holds it in place while you weld it. A wrap of paper round the bolt where it goes through the hole will ensure the nut is central.
Cheers,
Geoff.

Thanks Geoff,

That's a very neat way to do it. I have no way to weld it but one of my friends has a MIG.

[Glennet]

Good suggestion, Bohdan. It's a bit more work but certainly avoids the need for any special hardware. My smallest chisel would still push me to a bigger size nut but that doesn't matter.You only need to hold two opposite flats, like a spanner, so a slot would do.

[swk]

Paul,
if it was me I'd cut four pieces of 50 or 40mm x 3 mm flat bar, bore a hole in the centre appropriate to the nuts you want to use, weld the nuts on then bore four screw holes in the flat to connect to the underside of the dolly. The centre hole should be bored slightly oversize, a short bolt that suits the nut holds it in place while you weld it. A wrap of paper round the bolt where it goes through the hole will ensure the nut is central.
Cheers,
Geoff.

This is more or less the way I was going to suggest when I started reading the thread. If you cant weld the nuts, brazing was how I was going to suggest joining the nut to the plate. Soft soldering or even gluing with a good epoxy might even do at a pinch but they would probably let go over a while of use.
Instead of flat plate, large oversize washers. I found some 10mm "mudguard" washers of 50mm dia at the green shed when I wanted to make a knock down wooden trolley.

SWK

[BladeRunner]

You only need to hold two opposite flats, like a spanner, so a slot would do.

Of course, an open-end spanner is just two flats.

[BladeRunner]

If you cant weld the nuts, brazing was how I was going to suggest joining the nut to the plate.SWK

I'm going to have to address my current lack of welding/brazing equipment.

However, as suggested earlier, Bunnings actually sell 3/8" T-nuts (even though google doesn't make this immediately obvious). They're clearly big enough so I'll proceed with that solution for the time being.

Thanks to everyone for your helpful advice. I've acquired a lot of useful information.