Need help from the gurus

[DFR]

My sister gave me an oak board that her late husband milled some 30 years ago. I thought that I would make her and their kids pens out of it. I cut several pen blanks out of the board and glued them up and tried to turn them. On two attempts, I had the blanks about 90% turned when the blanks virtually split down the center. Am I doing something wrong? Poor glue up? Wrong speed? Or do I need to get the blanks stabilized? At a loss.

 

[keithbyrd]

Can you include some pictures?

 

[DrD]

Pics help. Then there is the obvious, if the blanks failed along the glue line, then it's probably the glue, the glue up technique or a combination of each. How were glue surfaces prepped? What type of glue? Glued with the grain or end grain? Were banks glued under pressure? How long did pieces cure before further processing? Where was glue line in relation to bore hole for brass tube? Und so weiter. Was drill bit sharp and/or did blank heat up excessively when drilled? Was gouge/or whatever tool sharp. What was the angle of the cutting tool in relation to the bore axis of the blank? What was turning speed. Was turning done using mandrel, and if so was mandrel heavily torqued.

Did blanks blow up or just split apart? Lots of possibilities. We really need more info to do a proper root cause analysis. And, no this is no some smart alec response to your request, just trying to put all in a better position to assist you.

 

[DFR]

Nowhere near the shop so pics aren't possible. I used two part epoxy for the glue up after drilling blanks and sanding tubes. I'm wondering if it may have been as a result of an elongated hole in the blank due to a wobble in the drill press.

 

[RProctor]

Nowhere near the shop so pics aren't possible. I used two part epoxy for the glue up after drilling blanks and sanding tubes. I'm wondering if it may have been as a result of an elongated hole in the blank due to a wobble in the drill press.

If there was a void between the blank and the epoxy that could most definitely happen with an elongated hole.....usually I have the blanks blow up entirely though. If you are concerned about elongated holes I would recommend drill on the lathe if possible or try a polyurethane style glue like Gorilla that has some expanding properties to fill the area

 

[Curly]

Cutting with a gouge or skew or scraping with carbide insert tools?
Any chance you missed a crack in the wood when you cut it up. Depending on how the wood was dried and how close to the end of the board you might have cracks in the wood. It is common to have to toss from 2" to 12" from the ends of a board when making furniture due to end checks (cracks). I was taught that if I couldn't see a crack to cut an inch off the end of a board and take that off cut and rap it on the edge of the bench or saw table. If it broke cut another inch and do it again. Repeat until you get to sound wood.

 

[DrD]

Pete, that's one my granddad taught me and I forgot; thanks for bringing that back into my rememberance!

 

[Curly]

You're welcome. My dad showed me.

 

[DFR]

Cutting with a gouge or skew or scraping with carbide insert tools?
Any chance you missed a crack in the wood when you cut it up. Depending on how the wood was dried and how close to the end of the board you might have cracks in the wood. It is common to have to toss from 2" to 12" from the ends of a board when making furniture due to end checks (cracks). I was taught that if I couldn't see a crack to cut an inch off the end of a board and take that off cut and rap it on the edge of the bench or saw table. If it broke cut another inch and do it again. Repeat until you get to sound wood.

This could very well be it. I cut a foot off the end of the board and then cut that piece into blanks. I saw no cracks but there very well could have been.

 

[jttheclockman]

No need to stabilize that wood. The end of the board could have stress cracks in it. As said try another section now that you are in better material. You do need to correct the elongated or oblong hole. Epoxy is fine for gluing in the tube if you make sure it sets and is cured before turning. When the hole is too large this presents problems when the blank is finished turned in that certain areas are now much thinner than the rest and those areas can crack easily when installing components and also when turning because now the pressure applied with tools varies on the density of the wood. Fix that and I bet you problems go away. Good luck.

 

[leehljp]

Its cases like these that make me appreciate polyurethane glue - no void spaces, even in cracks!

 

[jttheclockman]

Its cases like these that make me appreciate polyurethane glue - no void spaces, even in cracks!

The thing is it may not help. Look at my explanation.