Workshop accessory night: DIY-made Teflon/PTFE jaws

[THDplusN_bad]

Good Day,

I had a creative moment yesterday evening and have created a little helper, which is nothing less than a stroke of genius 

• This is an accessory for my small vise. It allows to hold small items such as leaded electronic components, wires etc. in place. It basically is a pair of jaws.
• The base material is 10mm Teflon or PTFE, so the jaws are heat-resistant. I never quite liked the old-style fixtures made out of a block of phenolic with holes.
• I have used my miter saw to make four cuts of a 10 mm thick PTFE plate. The first cut is limited in depth as to create a groove. This forms a narrow lip for the jaw. The second full cut separates the work piece from the base material. Repeat for the second jaw. As to hold the PTFE plate in place, I have glued four pieces of MDF down on a thin sheet of birch plywood - all around the plate.
• Drilled seven pairs of holes with diameters ranging from 0.5 to 3 mm with a drill press.
• I have then added a magic "auto-open" feature as follows:
• Drilled a 2.5 mm diameter hole into the two jaws. I have taken the steel insert from an old wiper blade, heated it up to cherry red with a standard lighter and pressed it through the hole. This melts the PTFE and forms a nice opening to hold it firmly in place. Removed and cut off the heated part from the steel blade and inserted a "fresh" cut-to-length part of it into both jaws.
• A slight bend of the inserted steel piece results in the jaws opening when the vise is released. This allows for one-handed action of the vise, so you can insert and remove small items very easily. This works nicely for pre-tinning work, trimming leads of components, general soldering etc.

Cheers,

THDplusN_bad

[Vince]

Didn't even know Joe public could buy PTFE blocks ? Where can you buy that stuff ? 

[BU508A]

Didn't even know Joe public could buy PTFE blocks ? Where can you buy that stuff ? 

Internet.      

[Vince]

Yeah just like Plutonium and assault riffles I guess but...

[BU508A]

https://www.ebay.com/itm/163690904140



NAWTS

[mnementh]

Much nicer-looking  than my latest fabricobbledy project!

That spring nickel steel strip in wiper blades has been a most favorite bit of project material for decades; as is the spring steel strip from old PendaFlex folders. That pre-made hook in each end has saved my arse more than a few times too.

As long as you don't need to drill holes in the stuff, both are "1001 uses" metal stock for sure. 

If you do need to drill holes in it... I recommend equal parts patience and Dremel with a diamond bit. It works.

mnem
 

[jpanhalt]

Nicely made.  I did something similar to hold 3 servo wires (hobby type) in position for soldering to 3-pin headers.  I didn't use Teflon, just notched the jaws of a spring jawed clothespin.  They are a little worse for wear, but after 20+ years, still usable.

[Conrad Hoffman]

Whenever I change wiper blades I save the steel strips. They have all manner of uses.

[Ian.M]

Its worth noting you can get glassfibre reinforced PTFE,  which has significantly better mechanical properties and machinability than pure PTFE.  Here's a supplier on Ebay: https://www.ebay.com/itm/281983650590 who will quote for smaller pieces cut to size.

If the vice has steel jaws, rather than a spring, consider using Neodymium magnets press-fitted flush into holes in the jaw face of the insert to attach it to the jaws.  Use three per insert, so you can center the hole you are using in the vice.

Dowel pins either end for alignment would probably also be worth adding.  Bore one insert for a press fit and the other for a sliding fit.   If the vice has non-ferrous jaws, coil springs could be added over the dowel pins for the auto-opening feature.  Counterbore both sides to accommodate the fully compressed spring, with (on the insert with the fixed pin) either a small pointed grub-screw from the end face to engage the last turn, or a reduced diameter at the bottom of the counterbore, to retain the spring.

[THDplusN_bad]

All good ideas - but I went for simplicity and functionality over any advanced features.
I may add some magnets. Most commercially available plastic and aluminium jaws use them.

Pure Teflon/PTFE is fairly inexpensive to get - I have paid 10€ incl. shipment for a 10 x 10 cm² piece with 10mm thickness.
 
I have also thought about dowel pins, but I have skipped the idea as the design is sufficient for my use cases. Not every workshop has the tools for the required precision work.
Admittedly, not every workshop has a miter saw and a drill press, which I had used. Alternatively, one could surely use a router for cutting the lip and a different saw to cut the work piece.

I'd be glad to see improved versions build by other members, of course!  Just keep them coming...

Cheers,

THDplusN_bad

[Vince]

https://www.ebay.com/itm/163690904140



NAWTS

Thanks.

Pretty cool, available in all sorts of dimensions and thicknesses. Very expensive but still affordable if you don't need 10kg of it... so it's a viable option for a small project every now and then 
Fiber reinforced PTFE as well... OK.

Oh, and looks like I will start saving my wiper blades now ! 

I should get 3 of them ... immediately. Their replacement is a bit overdue I must confess... now some motivation to order new ones just so I can salvage the strips from the old ones ! 

[jonpaul]

Hi: TAP Plastic in US sells Teflon Delrin, nylon sheets and blocks.

Jewlers pliers have rubber//neoprene jaw liners.

Certain especial Surgeon's instruments have similar soft jaws to manipulate delicate tissues.


Jon

[LaserSteve]

McMaster-Carr in the US.

[Brumby]

Whenever I change wiper blades I save the steel strips. They have all manner of uses.

Me too.

The first use was to make a lock pick.  I need to practice a lot more if I want to be reasonably adept - but it did work (eventually).

[thm_w]

Be careful overheating PTFE, it will release toxic fumes.
Soldering temperature is OK of course.

For the wiper blades, you don't actually need to order new ones you can just replace the rubber strip: https://www.aliexpress.com/item/1005002294371870.html
Get a good 1-piece blade and they should last forever.

[Haenk]

just replace the rubber strip

I can't see the point in doing so.
A brand new pair of wipers (OEM quality, but ALDI/LIDL-branded) is about 10 EUR. I certainly won't use an hour of my lifetime to refurbish the old, ugly ones, essentially saving almost nothing.

[coppercone2]

just be careful with parts, teflon likes to build up a charge, its used in exchange for rabbit fur in large vandegraff generators. Teflon as a charge carrier is how they get into the megavolt range.

[thm_w]

I can't see the point in doing so.
A brand new pair of wipers (OEM quality, but ALDI/LIDL-branded) is about 10 EUR. I certainly won't use an hour of my lifetime to refurbish the old, ugly ones, essentially saving almost nothing.

- Its not an hour of time, pull the old strip out slide the new one in, maybe 5-10min (if its a single beam wiper).
- Less waste of materials
- Better quality wiping material
- "OEM quality" means nothing. If they are "old and ugly" by the time the rubber needs replacing (~1yr), then the quality is poor. Probably old style wipers, not the newer superior single beam design.

[Renate]

The first use was to make a lock pick.

Don't you have street sweepers there? They are always throwing off these single steel brush spokes. They're tough and good for lots of things.

[THDplusN_bad]

Good Day,

alright, so here is Rev. 1.1. 

• I have added two small neodymium magnets to one jaw. I have sourced 10 small magnets sized 5 mm diameter and 2 mm thick from the online ex-bookstore we all seem to hate...
• Added two holes, located 15 mm from the outer edge. Teflon/PTFE is impossible to glue in my humble opinion, so I had to go for a good press fit. I have used a 4.5 mm drill with my drill press, and went for a slightly off-set second bore. Used a 5.5 mm drill in reverse to countersink. This leaves a few marks, but it works as PTFE is pretty soft. The mark on the lip is a minor bummer...
• I have used a 6mm punch to carefully tap the magnets into place. The magnets are holding the jaws in place quite nicely. I am very happy with the result.

Cheers,

THDplusN_bad