Threaded Bushes

istracpsboss · 05-25-2009, 03:58 AM

Hi

I'm making up a jig using threaded bushes. These are the type with an internal machine thread and a coarse external thread for going into the wood.
(Not the T-nut type with the spikes) They have an interrupted screwdriver slot in one end.

Can anyone tell me the correct way to fit them? They are very short and tend to cant over once the first part of the external thread bites. I've drilled a hole approximating to the core diameter. However carefully I start them, I cannot get them to go in straight. There is probably a very easy answer but I've not worked it out yet ! I did try with one, screwing a bolt into the back with a sprung sleeve on, to try to hold it straight, with limited success, but even that is impossible for blind holes where you can't get at the back.

Cheers

Peter

Noob · 05-25-2009, 07:23 AM

Two ways to drive them in straight. What kind of "head" does your insert have? The ones I have have a hex head in it, but I've seen some with a notch for a flathead screwdriver.

If you have a drill press and the insert is near the edge where you could drill it (not going to drill it though) you can do the following. Cut off a screw with the same thread pitch you are using (1/4-20 for example), then put that all-thread you just made into the drill press. Now put two nuts on it and screw a thread insert on the end. Now put a nut on it and then lock it with the 2nd nut. (the 2nd nut works as a jam-nut)Now HAND FEED the insert into the wood, then reverse and put on another thread insert and continue.

Another way to install them if this won't work for you is to cut a notch on the end of some scrap wood and drill a hole above the notch. Either clamp the jig down or hold it down firmly. Now you can either use an allen wrench or make the thread tool (all thread plus 2 nuts) and screw it in. Oh yeah, either put a nut on top with a jam-nut and drive it in or use a drill-driver with the clutch set so it won't strip.

See pic in case that's confusing.

**harrysin** · 05-25-2009, 08:16 AM

Having used heaps of these threaded bushes, some of my jigs have 32, it surprises me that you're having a problem. I must admit that all those that I have used are for an Alan key. If you do have a drill press it would only be necessary to hacksaw the end off an Alan key, leaving just the long part, pop one end in the chuck, the other end in the bush and hand turn to get started then take over with a standard key. I realise that you will have to return the slotted ones you have Peter for replacement.

**bobj3** · 05-25-2009, 10:17 AM

Hi Peter

Here's a little jig you make that will put them strait and true and easy with a tool you have in your shop..

just a note ,they do make a tool just for that job but a bolt with 2 nuts will do just find, just use some 2" x 4" ( 4" x 4" works best ) scrap for the jig...the bolt in the jig block keeps the insert running true..plus you have a small pocket to keep the insert back until you are ready to screw it in place.

Just put the jig block in place on top of the stock then use a driver ( ratchet wrench or battery drill ) and screw it in..

very quick,if you don't have a hex driver for battery drill just cut off a socket ext. that you can pop on socket to fit the hex bolt insert tool ...

==========

Quote:

Originally Posted by istracpsboss

Hi

I'm making up a jig using threaded bushes. These are the type with an internal machine thread and a coarse external thread for going into the wood.
(Not the T-nut type with the spikes) They have an interrupted screwdriver slot in one end.

Can anyone tell me the correct way to fit them? They are very short and tend to cant over once the first part of the external thread bites. I've drilled a hole approximating to the core diameter. However carefully I start them, I cannot get them to go in straight. There is probably a very easy answer but I've not worked it out yet ! I did try with one, screwing a bolt into the back with a sprung sleeve on, to try to hold it straight, with limited success, but even that is impossible for blind holes where you can't get at the back.

Cheers

Peter

levon · 05-25-2009, 11:14 AM

now that is very simple and smart. why cant i think of ideas like that. well at least we all know who can lol, Mr. Jigs! great idea!

**bobj3** · 05-25-2009, 11:40 AM

Hi levon

Thanks

,,,,,I think it comes from being so lazy

and cheap..and using what I have on hand,,,

When I got the inserts and the insert tool and it strip the slot out on the brass inserts and I could not get them in strait, I said, got to be better way ....

========

Quote:

Originally Posted by levon

now that is very simple and smart. why cant i think of ideas like that. well at least we all know who can lol, Mr. Jigs! great idea!

**Bob N** · 05-25-2009, 12:04 PM

BJ,

I think you have enough hardware in your shop to open a hardware store

GBM · 05-25-2009, 03:42 PM

That hex driver shown with the spanner blades and center pilot pin mounted in a drill press would be about as foolproof as it can get...on slow speed of course....LOL

**bobj3** · 05-25-2009, 06:07 PM

Hi GBM

It would be if it would not strip/pop out the slot and raise the edge of the brass insert and put on that nasty sharp edge that needs to filed down....

It takes a lot of power to screw them down in place and should be dirlled over size in hardwood..and must be counter sunk drilled b/4 the insert is put in place, they do like to lift the stock up if you don't..

Most drill presses don't have the power to do it..by the way..

======

Quote:

Originally Posted by GBM

That hex driver shown with the spanner blades and center pilot pin mounted in a drill press would be about as foolproof as it can get...on slow speed of course....LOL

GBM · 05-25-2009, 07:46 PM

Ok.. perhaps they need to be drilled and then tapped before inserting ? Is a tap matching those threads available ? If not then perhaps one of those fittings could be cut to make it into a tap of the proper thread gauge.... ?
Also, there are torque multipliers / speed reducers which can be chucked into a 'puny' drillpress if needed... with the added benefit of having a reverse on them.. which I assume would be needed to speed things up...

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