Taking off the corners of a square resin penblank with a tablesaw?

[Niels]

Hello,
I was wondering about something. A lot of penblanks are square and it's a messy job te round em for the collet chuck. I did see people making jigs to take off the corners with a bandsaw. I was wondering if anyone also did it with a tablesaw and if the results are good and what kind of setup they have? Photo's would also be great to have a look.

 

[showcaser]

Hello Niels, I've been thinking about a roundover bit on a router table. Just have to figure out a safe tool for holding the blanks to do so.

 

[boatemp]

The instructions for the Trim Router Table #LIXTRT on the PSI web site contains a photo of a material holder. It is item K in the instruction sheet. It can be used as shown but you can modify it to suit your needs. I've been using it for years with no ill effects. I round off blanks from 3-5 Inches and more. Just go slow, wear goggles and be careful. Use a good quality roundover bit. Does a better job than a table saw (dangerous) and fsster than a speeding bullet (a band saw). Good Luck, Frank

 

[tomtedesco]

FWIW, I use my disc sander to round over square blanks. I don't like the router bits or saw blades with small pieces that close to my hand.

 

[sorcerertd]

Someone here made and posted a jig a while back to round them on a router table. It may be in the resources section.

As for a bandsaw or table saw, a simple jig with a V shape should do the trick as long as you find something to hold the blank in place. I know I don't want my fingers that close to a moving blade.

Edit: Here's one by jig master @Wmcullen

Cutting Corners with Bandsaw

I'm not sure if this process is right or wrong; unique or common. But I want to share in case it's interesting. 28: Cutting Corners with Bandsaw last post- 27: Customized Zero Clearance Bandsaw Peg Jig (3d *.obj file attached) Tony mentioned he uses his bandsaw to remove corners from brittle...

www.penturners.org

 

[jttheclockman]

You see this question alot involving router, bandsaws, and tablsaws. To me it is a waste of time. You have a lathe. A lathe is designed to make things round. Just learn to use the tools and technique to turn things round. Even my segmented blanks which are always built square I turn them round on the lathe. But with that said there are jigs posted in the library and many threads on this topic. Good luck.

 

[its_virgil]

Let's race. Jig set up and roundover vs round over on the lathe between centers. For me...no contest. I'll stay with my lathe.
To each his own.
Do a good turn daily!
Don

 

[Painfullyslow]

Let's race. Jig set up and roundover vs round over on the lathe between centers. For me...no contest. I'll stay with my lathe.
To each his own.
Do a good turn daily!
Don

I would agree with one exception: segmented blanks. I always worry about the extra impact/vibration that comes from a tool striking a square corner. Those I round over on my belt sander first, otherwise I let the roughing gouge do its job.

 

[boatemp]

You said it my friend, "To each his own"

 

[KMCloonan]

Like Tom, I also use my disc sander to knock off the corners. This especially helps with Segmented blanks (less stress on the glue joints) and resin blanks (if I start turning a resin blank with square corners, I get a million little resin pieces flying around, or sticking to my hand, even when using my vacuum. Once the corners are rounded, the resin starts coming off in long ribbons.)

But, as mentioned several times above, to each their own.

 

[Niels]

Thanks for all the advice. I will think about the router.

 

[dogcatcher]

For segmented blanks that i think might explode I turn them between centers using my use my special "gouge" that is a 4 inch angle grinder with a 40 grit sanding disc.

 

[jttheclockman]

Thanks for all the advice. I will think about the router.

If you are thinking about a router let me warn you that the impact of a router bit striking a corner would be about the same as a well tuned sharp lathe tool. Think about it you are coming into the blank the same way as a skew. Unless you take real small bites it could even be more shocking. The safest way and least dramatic is to sand the corners being careful not to over heat. This goes for segmented blanks as well. One has to learn to control a turning tool and also keep it sharp. Do not be in a hurry.

 

[Niels]

A grinder sounds more ideal. I can experiment with it at home without making big investments. Thanks I got some new ideas.

 

[randyrls]

Neils; I have a 5" shopmade sanding disk mounted to the lathe. I use this for rounding off the corners of the blanks, and I use the same disk to square the blank ends. Mount the blank(s) on a mandrel and just go to it.

 

[Niels]

I have one of these. I could buy a grit 40 band and make a jig where the corner of the blank sticks out and grind it down. That's worth a shot and costs almost nothing before buying expensive tools.

 

[Niels]

A disc on a mandrel is also possible. And then hold it against it

 

[rherrell]

This topic always blows my mind, doesn't a lathe make things round?

 

[Niels]

Yes true but I just noticed the resin blanks chip like crazy and it flies everywhere including my face

 

[MRDucks2]

Yes true but I just noticed the resin blanks chip like crazy and it flies everywhere including my face

Ahh, the root cause of the concern. You are turning Inlace Acrylester or possible Rhino Plastic resin blanks. Using either carbide or a roughing gouge in a traditional scraping fashion to knock the corners off. Chips are flying everywhere and you aren't using a face shield.

With a 3/4" or larger spindle gouge, well sharpened, hold it between 45 and 90 degrees on its edge and ride the bevel similar to riding the bevel of a skew. This will help. You can do the same with a well sharpened skew.

Using your standard carbide tool, once again hold at about a 45 degree angle to the tool test and angle the cutting edge to a negative rake position.

Or, as many will say, get a negative rake carbide cutter or a negative rake carbide tool that uses regular cutters.

It is the type of resin blank you are turning. Neither blanks from most Alumilite products nor a regular polyester resin blank will be so "chippy" when trying to round using the methods you have used so far.

And do pick up a face shield. Even with different methods or tools.

 

[PatrickR]

Thanks for all the advice. I will think about the router.

Thanks for all the advice. I will think about the router.

This is what I use. A big time saver if doing a group of blanks. Center drill the blanks while square, run through 4 sides, then two passes on the lathe between centers and the blank is ready for a collet.
the horizontal router table is very useful. Plans from fine woodworking.