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View cjshrader's profile

Segmented pen blanks exploding frequently

by cjshrader
posted 08-20-2019 02:08 PM


17 replies so far

View ibewjon's profile

ibewjon

994 posts in 3303 days


#1 posted 08-20-2019 03:06 PM

I like to use a round carbide tool so if I am a bit off square, there is no corner of the carbide to catch. Give round a try..

View RobHannon's profile

RobHannon

317 posts in 1040 days


#2 posted 08-20-2019 03:32 PM

I have had this happen with mixed resin/wood blanks if I let the tool handle get too low. I ended up switching to a radius square cutter with a negative rake. Bit slower, but pretty forgiving.

Also in the pic, that segment that is glued in appears to have the grain running perpendicular to the rest of the pen blank. You are cutting across end grain there like you would be with a bowl. Sharp tools and solid anchor to the tool rest is going to be very important.

View TheDane's profile

TheDane

5690 posts in 4172 days


#3 posted 08-20-2019 04:30 PM

There is an oft-unspoken rule in segmenting … keep the grain running the same direction. Cross-grain glue-ups are a recipe for disaster, and turning against the grain will result in all kinds of tear-out.

I am not a fan of carbide tools … most of them are scrapers and tear the wood. Properly sharpened HSS tools slice the grain, leaving a cleaner finish.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View cjshrader's profile

cjshrader

4 posts in 60 days


#4 posted 08-20-2019 05:15 PM



I like to use a round carbide tool so if I am a bit off square, there is no corner of the carbide to catch. Give round a try..

- ibewjon

I’ll give it a shot, I never really considered the round tool for roughing. Thanks!


Also in the pic, that segment that is glued in appears to have the grain running perpendicular to the rest of the pen blank. You are cutting across end grain there like you would be with a bowl. Sharp tools and solid anchor to the tool rest is going to be very important.


There is an oft-unspoken rule in segmenting … keep the grain running the same direction. Cross-grain glue-ups are a recipe for disaster, and turning against the grain will result in all kinds of tear-out.

Thank you both! I think my logic was I wanted to prevent this so I was avoiding end grain to end grain glue up. However what you’re saying makes a lot of sense, I could see why this would give more of an opportunity for a catch. I made 10 blanks all at once, I hope some of them I made a little smarter but I’m not sure how much thought I was actively giving it.

View ibewjon's profile

ibewjon

994 posts in 3303 days


#5 posted 08-20-2019 06:08 PM

Many people hate carbide, but like you I need to get sharpening equipment and learn to use it. My belief is that a sharp carbide scraper is better than a dull shearing cutter till that time.

View Wildwood's profile

Wildwood

2740 posts in 2644 days


#6 posted 08-20-2019 06:55 PM

You would definitely have less trouble using conventional tools like roughing gouge or skew. JMHO might be pressing too hard on soft wood with you carbide tool like already mention might try round cutter just don’t press too hard! Just be little more patient! Also didn’t mention lathe speed but slowest rpm’s for me would be 1,000 rpm.

Think carbide tools excel at exotic hard wood, bone and stone on most domestic woods cannot beat convention tools. Know a champion bird caller uses his inexpensive conventional scraper on his calls normally exotic woods and domestic wood. He does do lot of sanding and doesn’t worry about sanding scratches. He sells every one he makes!
Good luck with it!

-- Bill

View cjshrader's profile

cjshrader

4 posts in 60 days


#7 posted 08-20-2019 06:58 PM


Also didn’t mention lathe speed but slowest rpm’s for me would be 1,000 rpm.

- Wildwood

Whoops I did mean to mention this. I go at the maximum speed of the lathe, which is 3200 RPM.

View pottz's profile

pottz

6351 posts in 1494 days


#8 posted 08-20-2019 09:31 PM

i use carbide tools all the time,love em,mostly the round.nice thing is when it gets dull loosen the screw give it a slight turn and you have a sharp tool again.i havn’t had any issues.

-- sawdust the bigger the pile the bigger my smile-larry,so cal.

View mel52's profile

mel52

1027 posts in 774 days


#9 posted 08-22-2019 03:23 AM

Just curious, but has anyone here rolled a carbide tool slightly to use it ( kind of ) like a shear type scraper. I have tried this and it does work on some projects with some woods. NOT trying to start an argument on if this is correct or not, just checking. Mel

-- MEL, Kansas

View gwilki's profile

gwilki

322 posts in 1983 days


#10 posted 08-22-2019 11:33 AM

If you don’t want to get into sharpening spindle gouges, think about getting a Hunter carbide tool. They cut. The ones that you are using scrape. You will never get the finish you are looking for off a scraper and as you have experienced, you will frequently get blow outs on segmented blanks.

-- Grant Wilkinson, Ottawa ON

View Andybb's profile

Andybb

2102 posts in 1113 days


#11 posted 08-22-2019 10:25 PM

This comes from many many many (20?) attempts at techniques that failed miserably after hours of building segmented blanks only to have them explode like a Hiroshima bomb.

1. Only use titebond if the segments are wood, otherwise use 2 part epoxy or thick CA. If you are letting them dry overnight you might as well use the 30 min kind vs the 5 min kind.

2. If you must use CA glue on the tube use copious amounts of thick, not medium. You will notice that even though you thought you used plenty of glue when the blanks explode off of the tube there is very little glue on there. CA glue has very poor shear strength so it separates from the blank.
Otherwise use Gorilla Glue or epoxy. If using Gorilla Glue wet the inside of the blank with a Q-tip as water activates it and it expands into the all of the little crevices.

3. Make sure to use compressed air (or your mouth) to blow all of the dust out of the tube.

I put plumbers putty in one end of the blank and coat the tube, stick and turn in one end then put more on the tube and stick and turn into the other end.

4. I haven’t used a barrel trimmer in years. Way too easy to tear a blank apart after spending hours building the segments. I use a disc sander.
It hasn’t ever failed me.

5. I only use the round and square radius carbide tools on segmented pens but some people love their standard HSS tools.

Then I switch to a VERY sharp Benjamins Best skew that I got from Ed at Exotic blanks. It gives me a 400 grit type finish. Then I use a flat strip if wood with some 400 grit stuck to it and run it back and forth or the blank for the final finish. When you get down to the end it’s just too easy to get a catch so sometimes I’ll even skip the skew and just use the sand paper.

The only sharpening tool I use is a cheap credit card sized hone on the skew and the carbide inserts. Just take the inserts off once in a while and with a circular motion rub them on the hone with a little oil (although I just use a little spit) for a few seconds. I have a low speed grinder that I have only used once or twice until I discovered carbide.

Keep everything sharp.



If you haven’t already join IAP for all things pen related. It’s like this site but for pens.

-- Andy - Seattle USA

View Andybb's profile

Andybb

2102 posts in 1113 days


#12 posted 08-22-2019 10:38 PM


Just curious, but has anyone here rolled a carbide tool slightly to use it ( kind of ) like a shear type scraper. I have tried this and it does work on some projects with some woods. NOT trying to start an argument on if this is correct or not, just checking. Mel

- mel52

Yep. But not on angled segments though as they can grab the seam and then BAM!!

-- Andy - Seattle USA

View Andybb's profile

Andybb

2102 posts in 1113 days


#13 posted 08-22-2019 10:57 PM

.

-- Andy - Seattle USA

View mel52's profile

mel52

1027 posts in 774 days


#14 posted 08-23-2019 01:06 AM

Thanks Andybb. Mel

-- MEL, Kansas

View Andybb's profile

Andybb

2102 posts in 1113 days


#15 posted 08-23-2019 01:36 AM



Thanks Andybb. Mel

- mel52

No problem. My choice for tubes is Gorilla Glue. No mixing like epoxy and it wont harden before you get the tube set like CA glue while you’re twisting and turning. Good luck. Let us know what works for you.

-- Andy - Seattle USA

View cjshrader's profile

cjshrader

4 posts in 60 days


#16 posted 08-23-2019 12:56 PM

Thanks Andybb, that information is very useful!

As a brief update, I did glue back together one of my exploded blanks and put it back on and use the round cutter, and I got good results with no more catches. I’ve ordered a radius square cutter for my tools and I suspect that will be a big help. When I make blanks in the future though I think I will take a lot more of this advice into account. Thank you everyone!

View Andybb's profile

Andybb

2102 posts in 1113 days


#17 posted 08-23-2019 06:00 PM


Thanks Andybb, that information is very useful!

- cjshrader


I’d be willing to bet that when you examined the torn out piece there was very little glue on there. Medium has it’s uses but just not for tubes in blanks I have found. If using CA (thick) I will also dribble some directly into the tube while turning it until it runs out the other end. Especially when there is a tight fit between the tube and blank there isn’t much room for the glue. That’s why i like Gorilla Glue.

-- Andy - Seattle USA

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