Grinding Screwdriver Bits

[thestelster]

I have to remove screws with extremely thin slots on a regular basis and often I have to grind the screwdriver bits to the proper size to remove those screws.

I use to do it by hand, and then a small 3-jaw drill chuck. But recently I purchased an ER11 collet for 1/4" hex bits from Mari-Tool in the US.

 

[Susquatch]

I have to remove screws with extremely thin slots on a regular basis and often I have to grind the screwdriver bits to the proper size to remove those screws.

Won't the bits from a Wheeler screw driver kit fit?

Didn't know you could get a 1/4 hex collet!

 

[thestelster]

I have the Brownells Master bits, and several of their thin bit sets. That will do 99% of all screws, but the high end stuff like Purdey, Holland & Holland, and number of the Italian manufactures have screw slots 0.010"-0.015" thick, as well as different widths. And they have to fit perfect or they'll get damaged.

I had to make a new screw for this FAMARS Italian side lock which was damaged.

 

[thestelster]

Didn't know you could get a 1/4 hex collet!

I didn't think so either, and then decided to Google it. MariTool was the only company I found that make a ton of odd ball stuff. I had to have it shipped to my brother in the US, and he brought it up.

 

[ChazzC]

It’s difficult to tell from the Wheeler website, but it doesn’t look like they have the super thin bits that Brownells sells (when they are in stock):

BROWNELLS MAGNA-TIP® THIN-BIT SET | Brownells

Check out BROWNELLS MAGNA-TIP® THIN-BIT SET | Brownells available Online at Brownells Today and many more Screwdrivers & Sets products are available in our Tools & Cleaning Department.

www.brownells.com

My Master Set & Thin Bit Set were some of the first tools I got from Brownells after Guy Lautard introduced them to me.

They also used to sell a rotary stone sized for touching up or modifying their bits:

 

[ChazzC]

I have to remove screws with extremely thin slots on a regular basis and often I have to grind the screwdriver bits to the proper size to remove those screws.

I use to do it by hand, and then a small 3-jaw drill chuck. But recently I purchased an ER11 collet for 1/4" hex bits from Mari-Tool in the US.

That is a great idea; I knew that Mari-Tool had hex & square ER collets, but didn’t make the connection for using them for touching up my 1/4” (or 4mm?) hex bits: another item moved up in the Wish List!

 

[TorontoBuilder]

I have the Brownells Master bits, and several of their thin bit sets. That will do 99% of all screws, but the high end stuff like Purdey, Holland & Holland, and number of the Italian manufactures have screw slots 0.010"-0.015" thick, as well as different widths. And they have to fit perfect or they'll get damaged.

I had to make a new screw for this FAMARS Italian side lock which was damaged.

I love how the screw head itself also has engraving.

 

[thestelster]

I love how the screw head itself also has engraving.

Yeah, this is what makes it difficult to replace. You make the screw, but the height of the head has to be much taller. You cut a sacrificial slot, but higher than the surrounding surface. You screw the screw into the plate which is mounted on a block. Clamp it in the milling machine, indicate horizontal, cut the new slot. Remove the screw from the plate. Clamp the screw, indicate horizontal, then cut to full depth. Now you have to trim the screw head height. But because the surrounding area is engraved, you better be darn careful milling it several thou' proud of the surface. Then the screw taken down on the surface grinder. Then test, and maybe another thou' and test, and another thou', until perfect. Then send to the engraver to match the rest of the engraving.

 

[Susquatch]

It’s difficult to tell from the Wheeler website, but it doesn’t look like they have the super thin bits that Brownells sells (when they are in stock):

They do, and it's readily available too. They are part of their 89 piece set. All different widths and thicknesses. I've never encountered a screw head it didn't fit. But I don't work on the high end stuff that @thestelster does. I suppose one could buy two sets and grind one set even thinner though.

Wheeler 89 piece set

 

[TorontoBuilder]

Yeah, this is what makes it difficult to replace. You make the screw, but the height of the head has to be much taller. You cut a sacrificial slot, but higher than the surrounding surface. You screw the screw into the plate which is mounted on a block. Clamp it in the milling machine, indicate horizontal, cut the new slot. Remove the screw from the plate. Clamp the screw, indicate horizontal, then cut to full depth. Now you have to trim the screw head height. But because the surrounding area is engraved, you better be darn careful milling it several thou' proud of the surface. Then the screw taken down on the surface grinder. Then test, and maybe another thou' and test, and another thou', until perfect. Then send to the engraver to match the rest of the engraving.

Yeah, it's a skilled trade for artisans. If it was easy the chinese would be knocking them off as easy gun mods

 

[ChazzC]

They do, and it's readily available too. They are part of their 89 piece set. All different widths and thicknesses. I've never encountered a screw head it didn't fit. But I don't work on the high end stuff that @thestelster does. I suppose one could buy two sets and grind one set even thinner though.

Wheeler 89 piece set

I saw the Wheeler 89 pcs. set, but while some of the flat bits are thin

I didn't see any bits this thin:

I don't know why Brownells doesn't show the sizes on their website.

 

[thestelster]

I saw the Wheeler 89 pcs. set, but while some of the flat bits are thin
View attachment 56315

I didn't see any bits this thin:
View attachment 56314
I don't know why Brownells doesn't show the sizes on their website.

Also, I don't know whether they offer it anymore, but they use to offer free replacements of thin bits if broken during use.

 

[Susquatch]

I didn't see any bits this thin:

I'll check when I get home.

 

[ChazzC]

Also, I don't know whether they offer it anymore, but they use to offer free replacements of thin bits if broken during use.

Yes, they replaced one of the 0.020” bits I chipped, but that was at least 20 years ago ( they didn’t need me to send the bit back, but I think I needed to pay postage):

Yes, I saved it: who knows, I may regrind it (after my ER16 hex collets arrive).

 

[Susquatch]

Yes, I saved it: who knows, I may regrind it (after my ER16 hex collets arrive).

Feeling guilty are we...... LMFAO!

I do that kind of thing too. Never know what kind of driver I'll need to make from that......

 

[PeterT]

I made a custom blade profile for a friend out of O1 that was wide but thin, hardened & tempered (torch & mini toaster oven respectively). It worked out well because the factory tool was apparently very expensive. His was used in a metric socket so the hex was milled to dimension. Unfortunately getting hex stock in O1 is not very common AFAIK.

 

[ChazzC]

Feeling guilty are we...... LMFAO!

I do that kind of thing too. Never know what kind of driver I'll need to make from that......

That’s why I the couple of times I bought used lathe bit lots on eBay I would usually find ~10% that were usable as-is (maybe a light honing), another ~10% were trash (too short/cracked/whatever; but still kept them in case I needed a short square piece of HSS) and the rest get separated by size into bins for future special profiles.

 

[PeterT]

I just finished making an index detent pin out of O1 that reminded me of this thread. It is a flat facet at a specific required angle, not the concave profile like some of the examples. Actually the concave could be made by feeding endmill equally from either side of stock, but I'd still leave allowance for finish grinding after hardening.

 

[Mcgyver]

I saw the Wheeler 89 pcs. set, but while some of the flat bits are thin
View attachment 56315

I've got that set.... working a lot of old machines and not wanting mar the old slotted head screws makes a gunsmiths hollow ground set a necessity. I found some of the bits (not all) to be poor quality. i.e. one twisted on me. Will take some photos when in the shop

 

[thestelster]

I've got that set.... working a lot of old machines and not wanting mar the old slotted head screws makes a gunsmiths hollow ground set a necessity. I found some of the bits (not all) to be poor quality. i.e. one twisted on me. Will take some photos when in the shop

The Brownells bits will generally break instead of bend, which is what you want.