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Screwdriver type manufacture 3

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Shawthing6927

Shawthing6927

Mechanical
Joined
Nov 30, 2017
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18
Location
GB
Hi,

I have a question regarding fitting a steel rod into a plastic handle.

For instance, if you was making a prototype of say a screwdriver, how would you connect the metal driver to the handle? I am hoping to not have to commit to tooling cost just yet so looking for a simple solution for a prototype. Obviously bearing in mind it needs to drive in screw etc. so must not come loose once fitted?

Any advice much appreciated.

Thanks.

 
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I'd carve the handle shape out of wood, then cast a glass fibre two part mould around the wooden model, using some sort of wax as a release agent. Paint the surface of the mould with PVA glue, or mre wax. Then fill the mould with polyester resin and short chopped glass fibres, and poke the screwdriver shaft in. Assuming you've copied the screwdriver shaft correctly that may work well enough.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376
 
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In addition to Greg's suggestion, I've noticed screwdrivers may have some 'wings' formed into the shank that gets a handle cast around it. That will provide some mechanical transmission of torque instead of just the adhesion of the cast material to the round shank.

This picture has a number of examples of what I mean:
URL]


Aidan McAllister
Metallurgical Engineer
 
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Or drill a small hole in the rod and then a small hole in the handle at 90 degrees to the rod and insert a pin or something to hold it in place and transmit torque.

Seems a very basic question??

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
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If it's very small, say instrument screwdriver size, then knurling the shaft may be enough.

But if it's a normal size, and a prototype, I would suggest drilling and putting in one or two cross pieces to hold the handle.
 
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What kind of plastic? Commercially made screwdriver and other handles were once made of a plastic known as Tenite, with the shank of the tool having a significant deformation to allow adequate grip. One could buy Tenite stock, drill a slightly smaller pilot hole, heat the tool shank to 200 to 300 deg F (??? need verification), and press it into place.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
 
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Shawthing6927:
You might also cast the plastic handle onto the cooler steel blade, so that the plastic would shrink to the roughened blade shank.
 
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What about machining a hex end that fits common handles with removable tips? I assume your unique design feature is the tool (bit) end and not the handle!

Walt
 
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Shawthing6927,

Watch Forged in Fire. This is on Spike TV, but episodes are up on YouTube. They are making all sorts of fancy combat knives, which are way more interesting than screwdrivers, but they do have to attach handles.

--
JHG
 
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1. FYI...

ASME B107.600 SCREWDRIVERS AND SCREWDRIVER BITS
This is the 'big kahuna spec' for everything screwdriver and SD-bits... with exception of a few standards for screw-drive recesses/tool-tips typically used in aerospace.

Prior specs [CX'd]...

MIL-B-9946 BITS, SCREWDRIVER, GENERAL SPECIFICATION FOR
MIL-B-9946/1 THRU /20, BIT, SCREWDRIVER,... ...

MIL-B-85643 BITS, SCREWDRIVER, RIBBED, GENERAL SPECIFICATION FOR
MIL-B-85643/1 THRU /5 BIT, SCREWDRIVER,... ..., RIBBED,...

2. Another idea for a 'simple prototype screwdriver'...

Get a short section of PVC pipe ~1.00--1.25-OD and the glue-on plastic seal-caps, PVC cement, generic 2-part epoxy resin... and alcohol or acetone and clean cotton cloths.

Drill hole in one end-cap, on-center, for inserting the screwdriver shank; and a 'hole-start' in the interior/center of the second cap [for 'blank-end' of screwdriver shank to 'set-into'].

Clean interior surfaces of the plastic parts [tube/caps] 'break-water quality'.

Cement-on the end-cap with drill-start.

Grit-blast screwdriver shank to attain 'bright metal' finish.

Insert drive-shank thru the hole in the remaining end-cap.

Pot-fill the capped-off tube section [~90%?] with 2-part epoxy resin.

Insert The screwdriver shank into the epoxy resin until it seats in the 'drill-start'; then cement the end cap in-position. OK to add/remove epoxy just before this step.

Fillet around the shank/cap [exterior] with excess epoxy resin.

Might consider coating the 'handle' with PLASTISOL colored-coating for a 'softer feel'.

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]
 
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Big star to Walt Strong.

I believe this is the ~ $10 dollar solution he was referring to.



Eminently suitable for a prototype.

When production begins -
Say it is for existing 5/16 hex drive
Provide a 6 in 1 screwdriver with bits
Glue your driver into a commercial handle and send me all the extra bits.​
 
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how about buying someone else's screwdriver body and adding your bit to the end ?

maybe sell only your bits (that fit a universal screwdriver) ?

another day in paradise, or is paradise one day closer ?
 
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