Drilling largest diameter holes - Suggestions

[Krash]

I need some advice on drilling.

Some of you may have seen my Ark of the Covenant pen made using an Atrax kit. It used 10.5 and 12.5 mm bits. I was very worried about the blank blowing up, especially since I have used brass before and it has given me issues with catching and separating. I was determined to keep it from happening this time.

I use a Nova G3 for drilling so I inserted the blank with the brass segmenting in the jaws in hopes that it would support it more. I used 8-10 drill bits, stepping up slowly. For the upper barrel, the last step was from 10.5 mm to 12.5 mm since I don't have anything between these. It got almost all the way thru but did separate the segmenting. It was a pretty easy glue up. The lower barrel drilled fine until the 10.5. It went thru fine but caught the brass when pulling back out. Complete separation. I fixed it but wonder what I could've done better.

So, you guys who have done this type of segmenting, do you have any suggestions or tricks for drilling?

 

[Ed McDonnell]

Hi Kelly - You can sharpen a drill bit to dramatically improve it's performance with brass (and plastics). Done right it will eliminate the grabbiness of drilling brass (and the chipout of plastics at the exit hole). That may help eliminated the stress that is delaminating your blanks. Tuning the bit for brass will seem like dulling it, but it's not dull. The cutting geometry is just modified.

You can search the web for "sharpen a drill bit for brass" and get a lot of hits.

Here's a link to a video (it's talking about drilling plastics, but it's the same for drilling brass):

How to Make a Twist Drill Safe for Use on Brass and Plastics - YouTube

Here's a link to a discussion with a picture that should help give you a better idea of what you are trying to do. It's about the fourth post down:

The Home Machinist! • View topic - Drilling brass

Drill bits sharpened for brass / plastic will not work well on steel, but they should still be good for wood. Of course, if you modify your drill bit the wrong way, it won't drill anything well. In that case, just sharpen it on your drill doctor and try again.

Once you get the hang of it and get your bit sharpened just right, you can probably use a lot fewer drill bits as you drill larger holes through brass.


Ed

 

[skiprat]

Use a boring head. You can't beat it for drilling big fragile holes.:wink:

 

[Krash]

Wow Ed, that is a very interesting concept. I would have assumed that the bit needed to be sharper, or at least sharp like it was supposed to be. Grinding it to be a 90 degree scraper so it doesn't auger in is brilliant. They said they used it on hardwoods also. I experienced this drilling ebony. I gotta give this a try!

Thanks so much for the class, teach!

 

[Janster]

...you may also consider wrapping your blanks with masking tape before drilling. I generally drill any metal segments to size before glueing up the blanks. I just glue the wooden piece, add the segment and you can do that easily as many times as you wish directly on the tube, put in a vice and let it cure! ..Jan

 

[plantman]

Kelly; When I drill segmented blanks I start by coating the blank with thin CA. Next I rwap the blank in duct tape or reinforced packing tape. As I drill from smaller drills to the size I want, I soak the inside of the blank with thin CA every drill size change. This will hold together any cracks and fill small voids. Drill slow and back out often. Don't use brad point bits. Jim S

 

[Krash]

Great tips guys.

Thanks!

 

[Ironwood]

I saw a tip from George ( robutacion ) a while back, where he suggested for drilling his crosscut blanks, to glue some wood strips on the four flat faces of the blank to prevent breakages while drilling.
I have been doing this on my segmented blanks lately, I haven't had one separate on the glue lines since I have been doing it. It does mean a bit more work, but saves on redo's.

I tried to find George's post, but couldn't find it. He had photos.

 

[hebertjo]

2 other ideas…

1.) On round blanks you can wrap cotton string (like they use in cooking to hold the meat together) around the blank and then soak it with thin CA.

2.) From Eagle, wrap gauss around the blank and soak it with thin CA. This works for round or square blanks.

I have tried both with great success.

 

[glycerine]

Slow and steady... or slow at least. On segmented stuff with metal, I will usually drill a bit and then stop and give it time to cool. Do a bit more, then rest again. keep the pattern going until it has a hole through it! Might not be ideal, but keeping the temp down is the key with metal segments. And I will usually glue a small sacrificial cutoff to the back end when drilling to keep my bit from "breaking" through...

 

[Justin H]

Hi Kelly - You can sharpen a drill bit to dramatically improve it's performance with brass (and plastics). Done right it will eliminate the grabbiness of drilling brass (and the chipout of plastics at the exit hole). That may help eliminated the stress that is delaminating your blanks. Tuning the bit for brass will seem like dulling it, but it's not dull. The cutting geometry is just modified.

You can search the web for "sharpen a drill bit for brass" and get a lot of hits.

Here's a link to a video (it's talking about drilling plastics, but it's the same for drilling brass):

How to Make a Twist Drill Safe for Use on Brass and Plastics - YouTube

Here's a link to a discussion with a picture that should help give you a better idea of what you are trying to do. It's about the fourth post down:

The Home Machinist! • View topic - Drilling brass

Drill bits sharpened for brass / plastic will not work well on steel, but they should still be good for wood. Of course, if you modify your drill bit the wrong way, it won't drill anything well. In that case, just sharpen it on your drill doctor and try again.

Once you get the hang of it and get your bit sharpened just right, you can probably use a lot fewer drill bits as you drill larger holes through brass.


Ed

Wow... this is pretty much bass ackwards of everything I've learned about drilling pen blanks... lol

I can't argue with his results, I just don't understand at all how it works

 

[Krash]

I know, right? It really does work well.

 

[robutacion]

I saw a tip from George ( robutacion ) a while back, where he suggested for drilling his crosscut blanks, to glue some wood strips on the four flat faces of the blank to prevent breakages while drilling.
I have been doing this on my segmented blanks lately, I haven't had one separate on the glue lines since I have been doing it. It does mean a bit more work, but saves on redo's.

I tried to find George's post, but couldn't find it. He had photos.

Thanks for your referral, the thread you are talking about is this

Reading through the other posters, I can see that, most of the more important advice as been given, if I would add something, it would be the suggestion made on my above thread link and the fact that, many blanks are damage from the removal of the drill bit from the hole while turning, you can avoid that possibility to trouble by simply turning the lathe, bench drill press off, after you exited the drill tip on the other end/bottom...!

But, the best tip of them all is to small the hole small (less forces) and soak the inside the hole with super thin CA, unless is super thin (5 cups), you want have much CA penetration, and do it for every drill size up...!
Accelerator will set the CA quite fast but, you cam always assist the hardening process by introducing a heat gun to get the CA reaction going through its full thickness. If it happens that the CA is not fully cured, your drill will come out pretty messed up with CA that, you have to clean before using it again. Acetone, covering the drill bit, will take care of the CA without using a knife or any other tool that can easily damage the drill bit skirts...!

Cheers
George

Cheers
George

 

[NittanyLion]

I would suggest a complete drill bit set. I've used 27/64 and 15/32 in step drilling Jr. Gents that were heavily segmented.

 

[farmer]

boring Drill guns or bits

I need some advice on drilling.

Some of you may have seen my Ark of the Covenant pen made using an Atrax kit. It used 10.5 and 12.5 mm bits. I was very worried about the blank blowing up, especially since I have used brass before and it has given me issues with catching and separating. I was determined to keep it from happening this time.

I use a Nova G3 for drilling so I inserted the blank with the brass segmenting in the jaws in hopes that it would support it more. I used 8-10 drill bits, stepping up slowly. For the upper barrel, the last step was from 10.5 mm to 12.5 mm since I don't have anything between these. It got almost all the way thru but did separate the segmenting. It was a pretty easy glue up. The lower barrel drilled fine until the 10.5. It went thru fine but caught the brass when pulling back out. Complete separation. I fixed it but wonder what I could've done better.

So, you guys who have done this type of segmenting, do you have any suggestions or tricks for drilling?

Allot of custom cue makers us a drill gun.

Its a long drill bit that has been bored down the center and air is supplied to the bit.

The air blows out the chips and lowers the friction temp of the bit.
The bit goes in the tail shaft of a engine lathe.

I can bore a 5/8 hole in ebony 12inch deep in less then a minute in a single pass.

If you need me to hook you up with the guy that makes these drill guns then PM me...................


Farmer

 

[Carl Fisher]

gauze wrap and thin CA should do the trick.