Trouble with long barrel Part I

[harik.raif]

Hi, I am having a couple of problems making pentel mechanical pencils. I guess I'll split this into two posts.
1) drilling.
I have purchased a nice stepped drill bit and mandrel from ... beautiful something . My crappy drill press only has like 2" or 1 7/8" travel and really doesn't seem usable for drilling these blanks which are 4-3/8" long. So I have been drilling them on my lathe. Problem is of course, they are square, or more precisely rectangular. I rough turn the blank down a bit and create a 5/8" tenon so to speak. I created a sort of clamp ... thing. I think someone on here probably advised me. I put a piece of wood in my chuck, drilled a 5/8" hole, then cut a kerf ( sp? ) from the hole to the edge. Then once it's back in the chuck I can tighten it down, sort of, and it grips the blank, sort of.
The main problem is that I can't get the bit to drill straight. I starts wobbling and then gets worse then pokes out the side at about 3 + inches. Some things I've checked/tried:
1) the head and tail stock are aligned
2) pre-drilling, just like goldie locks with a thin bit a medium bit and the same size bit but a short one. I put the bit in the chuck as far as possible making it as short as possible to provide the most rigidity. While this helps it does not solve the problem.
3) I've tried with the lathe turning very fast as well as slow. It seems when it's going very fast at the beginning it might be a little better.

I burned through 4 blanks the other day trying to get 4 usable ones ... so 8 total.
Not sure what else I should try. Any suggestions would be appreciated.

 

[KenB259]

Can you supply a picture of your tooling? Doesn't sound like things are being held very well.

 

[harik.raif]

Can you supply a picture of your tooling? Doesn't sound like things are being held very well.

Yes, I should do have done that. I have meetings all day, but I'll take some this afternoon and post them.

 

[Chasper]

I've never been a big fan of drilling on a lathe, so first off I will describe the way I use my step bit to drill blanks for a Pentel pencil mechanism. It is difficult to re-sharpen a step bit so I only use it for the final 3/4 inch of the drilling.
1. Put the squarish blank in your drill press vise with it sticking out the top.
2. Use the longest jobber bit you can find in the proper diameter. Drill in short distances, 1/2-3/4 inches, and clean out frequently, small flutes clog quickly, especially if you are using an oily wood.
3. Drill down to the maximum depth your spindle will travel.
4. Raise the table of your drill press and/or move the blank up in your vise to about 90% of the depth you drilled and continue drilling. You may need to lower the table to clean out the bit as you drill.
5. Repeat step 4 over and over until you have the hole down to the needed depth
6. Replace the straight bit with the step bit and drill the last 3/4 of an inch.

If you insist on using the lathe to drill, try this.
1. Mount a 2MT drill chuck in the drive side of your lathe. Put a 60 degree live center on the other side.
2. Use a starter bit to drill a countersink like hole at the exact spots where you want the hole to start and finish.
3. Hold the blank steady with a channel lock pliers.
4. Position the blank at the starter hole and the live center at the desired exit hole and drill slowly, repeating steps 2-6 above.

With either method, you don't have to drill all the way through, only go as deep as the hole needs to be. Trim to final size after turning.

 

[harik.raif]

Chasper, Interesting ideas. I might try the lathe version first, probably on some scrap and see how well that works. I know the drill press version will work but it sounds like a big pain. Well I guess it is either way. If you are using the drill press, I'd be afraid of the hole not going in the proper trajectory. Is it ok to just eyeball it? Once it's started the horse is out of the gate so if it's only the beginning that matters I guess.
Thanks,
R

 

[Bats]

1. Mount a 2MT drill chuck in the drive side of your lathe. Put a 60 degree live center on the other side.

One caution on this - you generally don't want to use an MT drill chuck in the headstock without a drawbar - otherwise it can pop out while spinning and cause all sorts of excitement (not that I've ever done anything like that... more than two or three times). You might (might) be able to get away with it in this case - if the tailstock is always holding the blank in place and you shut off the lathe before each retraction, but it's probably not a good practice to get into.

If you're lucky and the back end of the chuck's taper is threaded, you can make a quick & dirty drawbar with a length of appropriately sized allthread, a washer, and a nut (or, if you're feeling fancy, a hardware store knob, if they've got one with the right threads) to cinch it down.


-Bats

 

[skipseke]

I'm fairly new here but I found a dedicated pen blank from PSI.Mount it in the head stock and the drill bit in a Jacob chuck and slowly drill the blank clearing often. Seems to work for me.

 

[Bats]

I'm fairly new here but I found a dedicated pen blank from PSI.Mount it in the head stock and the drill bit in a Jacob chuck and slowly drill the blank clearing often. Seems to work for me.

I do the same with the Pen Plus Jaws on a Nova chuck. Things don't always go according to plan - the drill still seems to drift from one end to the other on occasion (usually when it's most critical that it doesn't) and if the blank isn't perfectly square or hasn't been turned to a perfectly even diameter, the results are unpredictable - but it works out better for me than a drill press. Being terminally broke, though, I'm always reluctant to offer "Just buy this new gizmo!" as a solution.


-Bats

 

[skipseke]

I do the same with the Pen Plus Jaws on a Nova chuck. Things don't always go according to plan - the drill still seems to drift from one end to the other on occasion (usually when it's most critical that it doesn't) and if the blank isn't perfectly square or hasn't been turned to a perfectly even diameter, the results are unpredictable - but it works out better for me than a drill press. Being terminally broke, though, I'm always reluctant to offer "Just buy this new gizmo!" as a solution.


-Bats

I know what you mean same here not near enough money for a wood turner being retired .Wife ssid Bill's come first.What a dumb rule.

 

[howsitwork]

I suggest NOT using brad point otherwise known as lip n spur bits. These have a tendency to follow the grain in the blank.

frequently pull out to clear chips from the flutes.

Ideally you want a short , stiff " stub drill" to start the hole then follow with a longer one when established. Yes I too don't follow this advice and often get away with it but it's still valid.

Oh and check the drill bit for straightness too as well as running it and looking closely at it in situ . Is it being held true in your chuck ? Always tighten chuck with all the pinion holes so jaws are equally tensioned, sounds odd but believe me it CAN make a difference.

let's see the photos before further suggestions please ?

 

[Alchemist]

Okay… so, it seems like your bits are drifting. My experience is this:

I started turning pens with a shopsmith as a lathe. The reason I mention this is because of what I learned. Shopsmith a headstock moves. The tail stock is stationery. However, the lathe drilling is the same process.
MT2 drill chuck in tail stock. Blank in four jaw chuck.
Stay away from brad style bits. As another person pointed out, they are prone to follow the grain. I'll explain how I know further on.

Now, on my other lathe, a laguna 12/16, I was drilling blanks. I misplaced my 7mm jobbers so I used my brad points. Drilling fast or slow… doesn't matter they rarely come out centered.

So, I use jobber bits and move the drill bit into the blank when needed by moving the tail stock closer to the blank.
1/4 inch drilling's followed by clearing. Brad points just tend to wander.

that's my two sense.

 

[RobS]

My apologies, I am short on time, so I have not read every reply. I have however have made several of these.

1) you will need to round the blanks first to prevent blowing out the front.
2) Once the blank is round, drill it, using a drill that is the same diameter as the step drill major diameter. Only use the step drill when you get close to the final depth. You could start with a center drill, then a short stubb drill for 1/8" depth, then your longer brad point drill to help prevent wandering. You can drill the blank in the pen chuck on the lathe or on the press. Note the blank must be about 1/8 -1/4" longer than needed this will give you strength at the front. So when you drill you want to remember that.
3) once drilled, use Rick Harrell's Sanding jig to square the front and to dial in the correct length in the front. I check it with a pentel pencil, loading it in and seeing when it seats correctly (make sure to knock out all the dust first).
4) now turn it down.

You should turn round before drilling, to prevent high loads that blow out the front after drilling.

GOOD LUCK

 

[MRDucks2]

David may be on to something that has not been mentioned. If you are advancing the quill in the tailstock, the quill lock must be very snug in some lathes to prevent the quill from wiggling in the tailstock. If advancing the entire tailstock, the quill lock should be tight and the tailstock needs to be very snug to prevent the same issue.

Yes, this is experience speaking.

 

[harik.raif]

MrDucks2 I hadn't thought about this part. I usually secure the tailstock then crank the quill. Lots of hand turning. But I don't turn the tightening handle down to just before it stops the quill. I don't know how much play it has I'll check later.
BUT,
Chasper, I have tried the technique you/he described for drilling it on the lathe and it worked WAY better and was WAY less work. That said, it's not fool proof, or at least not this fool proof. It took me a couple iterations to get the thing going pretty straight. Here is my process.
1) mark both ends of blank
2) take a small drill bit maybe 3/32nds but not important, and drill an 1/4 inch on one end and just an 1/8 or so on the other.
3) put the jacobs chuck in the head stock with a pre drill bit as many have described
4) on the lathe put a live center in tailstock with a point in it, a sharper point is best because
5) put the point of the live center in the 1/8 hole, the hole really helps make certain that you are actually driving it from the right spot
6) grab the blank with channel locks
7) use the 1/4 inch hole as a starter.
8) drill away
So here is one other thing. The step drill and mandrel are 17/64, not that easy to find especially a long one. So I used a slightly more narrow bit went down like 3-7/8" then used the step drill. No bueno. When I went to put the mechanism in to test it, it seemed the step started right at the edge of the main hole rather than the center! Doh! So, I either need to get a proper 17/64 long bit or just use the step bit. So the 17/64th is going to be at least some $12 - $15. I went to theperfectcollection.com but their product page is down. If a step drill is in that price range I don't see much point in bothering with a pre drill bit. Hopefully they will get their sight back up.
R

 

[RobS]

17/64 extended at McMaster Carr:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[harik.raif]

That is a good bit but with shipping and tax it's almost $19. I heard from perfectcollection, it's around $25 with shipping so that's not great either.

 

[harik.raif]

In the second part of this thread Trouble With Long barrel Part II someone posted an article on how to make pentel pencils with 7mm tubes. It's pretty great.

 

[harik.raif]

So I have given up. Between the drilling and the blowouts ( see part II ) I am super frustrated. As I mentioned above, in Part II there is a post explaining how to use these pentel guts in a 7mm tubes and that seems more due-able. It's a good article article and provides sources for parts as well a cool technique for getting the pocket clips onto the pencil.
I have definitely learned a great deal through this process an this thread. At the cost of crushing my soul. Just kidding. But I'll be glad when I have a consistently reproduce able technique. At which point I will probably never turn another pen or pencil again in my life. But life is an adventure not a destination.
Thanks