Trying to drill 4mm hole in 3mm stainless steel (A2) Washer...

and failing miserably!

The way I did this was to stack some washers and press them into my collet chuck as a 20mm stack then tighten the chuck. The drill just snags and rips them out one at a time... too much drill pressure and the washers are forced out of the collet.

I only want two washers drilled. I've managed one, which is OK but ruined a dozen trying to get a second.

Whats the smart way to do this? (I have considered turning down a 4mm washer to the right OD as an alternative, but suspect I'll have a similar problem with this material.

Steve

A collet chuck is not going to grip (a very short part) well enough. I have done jobs similar to what you are trying to do with a normal 3 jaw chuck. Most jaws have notches and if you can grip the washer by its edge partway down the jaw length, there is still probably enough room for the drill.

Alternatively you could just grip the washer very carefully at the mouth of the 3 jaw and use a small boring tool.

Ian

Make a small split bush drilled 4mm and with a shallow recess to suit the washer OD, this will grip the washer and keep it true.

j

Hi Steve, Jason has discribed the photo below that I have just uploaded, i.e. a split bush with a recess to fit into your collet chuck or three jaw.

Regards Nick.

Having had similar problems drilling and boring washers, I have found it is often easier and faster to make a custom one with desired OD and ID on the end of a suitable piece of bar and part it off at desired thickness, instead of modifying an existing one. Stamped stainless is especially hard to hold to modify, the drill always snatches, and being stamped, the rollover (rounded top edge) and the fractured area of the OD make a very small contact area cut by the die for gripping.

Machining off bar works every time, no snatching and grabbing, or fancy collet making needed. (although the collets in Nick's photos are clever and look well made, and likely will work well.)

JD

Thanks for the responses, this is what the washers are for. If you pick this image up from the album and zoom right in, I think it shows a plain 4mm washer as lacking a bit of finesse (see top washer) compared with the lower washer, which is 3mm drilled out to 4mm.

I think the easiest way to do this then, is simply to make a washer from stainless bar.

Thanks for the help.

Steve

PS: I wasn't in total hibernation all Winter! Just that that Whittle engine is very demanding, frozen fingers and icy tools just don't cut it, if you pardon the pun...Progress anticipated soon.