Tapering Masts and Arms the easy way

[Johnny Mike]

All the information I have seen on tapering dowels for masts and arms 

is by a lot of hand sanding or turning. I have done it this way myself and it was time consuming and I had to guess at the taper for continuity.

And being a novice it was difficult to get matching results.

 

I tried something that works to get a consistent taper quick and easy. 

I took my disc sander and clamped on a guide to the angle I wanted and simply hand fed the dowel in while rotating it by hand. I had a perfect taper from 12mm diameter to 9mm in diameter in 8". Exactly what I wanted in just a few minutes.

Maybe this is common practice for the expert builders but being a novice builder is was an amazing discovery for me.

[Loracs]

This is a good idea, simple and straightforward. Look like quite precise too.

[Nirvana]

Way to simple solution....😆

No wonder I didn't think of that.

[BritByker]

Thank you.  Doing this next time!

[GGibson]

Looks interesting, Johnny Mike!  And I have a Proxxon disk sander.  Just trying to actually determine how the block guide is set up and how the dowel is fed.  Is the dowel just fed from the side to the sander's mid-point?  Thanks for clarification.  

[palmerit]

Another solution is to put an end of a dowel in a power drill (wrapping the end in paper of cloth so as not to intent it). Maybe that’s what you mean “by hand”. I use a clamp to keep the drill turning. Then use various grits of sandpaper to shape. Way better than trying to do it by hand, with a blade, or with a plane - at least for me. Need digital calipers to measure. 
 

This approach could work great so long as you get the angle right on the pieces (and could be more efficient) - if you have a power sander (I have one for big pieces, my hobby one is a non-powered Ultimation). 

[Nirvana]

7 hours ago, BritByker said:

Thank you.  Doing this next time!

BritByker, Welcome to Model Ship World!

[Y.T.]

18 hours ago, Johnny Mike said:

I took my disc sander and clamped on a guide to the angle I wanted

Can you please provide more details? I didn’t understand. 

[palmerit]

This approach works if you have a constant taper - or just want to do the first pass at a taper and then fine tune. Some of tapered masts and yards I’ve had to do aren’t linear. 

[Kauz]

Using a stop block, you could do it in different settings to get a gradual taper, i.e. first setting with slightest taper, second with a steeper angle farther out on the yard/mast and so on. You'd only have to hand sand the transitions.

[Johnny Mike]

Thanks for all the comments.

To answer a few questions.

The block I was using is just a start to try. More defining will be done.

I think this is even simpler and better than you might think

and if you try it you will see how easy it is to get really professional results.

 

Attached is a picture with two scales. If you measure the gap between the block and wheel you can set up for the exact finished diameter and it exact every time. It is easy to change angles by simply repositioning the block. 

 

It is east to repeat angles and for yard arms both ends are exactly the same. For pros this may be easy but a novice like me has a difficult time getting matching angles sometimes, and it is time consuming.

 

Another picture shows the mast in the sanding position.

I thought I might have a feed problem doing it by hand while turning the mast but it was surprisingly easy and was no problem. You just have to be firm and steady with your grip and feed and have the sanding disk do the work. Don't force it. I was thinking I might have to add something to help turn the mast while I fed but found I did not need to.

 

The first mast I ever tried is in the picture and did 3 more yesterday. All are spot on. 

 

I found it best to use 80 grit paper.

That sounds aggressive but needed to get the job done.

It is easy to use 220 by hand to finish.

[Y.T.]

Well. I got the idea. Issue is you can only machine the length of dowel equal to half of your grinding wheel diameter. What when you need a longer taper? Another limitation I see is when one needs to taper a small diameter dowels as 3 mm to 2 mm for example. The grinder may chew on the dowel.

Edited Saturday at 06:33 PM by Y.T.

[Johnny Mike]

The first taper I did was 8" long. I use the complete wheel face.

 

I just did a 5 mm yard arm. I put piece sheet of thin wood on the table

up against the wheel so no gap.

 

Of coarse everything has limitation.

[Y.T.]

1 hour ago, Johnny Mike said:

Of coarse everything has limitation.

I agree. Also your idea is new to me and good in some circumstances. Enjoy discovering a pleasure of ship building.

[Dr PR]

Are you using the same taler for the full length of the mast? A long tapered cone?

 

From what I have read the mast is more like a long half oval, tapered more on a curve than a straight line. Widest at the deck (partners) and tapered in quarter lengths in a non-linear fashion.

 

Divide the length of the mast from the deck to the crosstrees into four sections. The relative diameter at each quarter is:

 

deck (partners)              1.0

1/4                                   0.984

2/4                                  0.933

3/4                                  0.857

crosstrees (hounds)      0.75

 

I used to use a simple taper using sandpaper for the masts when I first started building ship models (50+ years ago). But when I learned real mast weren't built this way I started using the 4/8/16 tapering method in order to get better control of the mast shape. It is a lot easier that it sounds, and produces a more accurate mast shape.

 

YT pointed out a problem with your method. With a disc sander the rate of material removal is proportionate to the speed of the sanding surface. The outer parts of the wheel rotate faster, and the center doesn't rotate at all for practical purposes. You can't use the entire diameter for tapering because the center doesn't  do much, if anything. You can modify the process by placing a spacer to raise the work piece above the center, so the sanding surface is moving, but it will still be faster on the outside of the disk than near the center, and will be more aggressive at removing material. It will be very difficult (but not impossible) to get an accurate mast taper this way.

 

[wefalck]

That's a good idea for making tapered dowels and I seem to remember to have seen a similar procedure in the wide realm of YouTube, but not for model building.

 

As others have already pointed out, masts and other spars are often not simply tapered and in addition have square or octogonal sections.

 

Having observed that, I think the disc-sander method could be a good idea for quick material removal to arrive at the envelope of the more articulate shaped spars. After that, one would need to resort to another method to give them the exact shape.

 

[CDR_Ret]

Regarding mast tapers (and this applies to spars as well), applying the tables found in Underhill's book for the latter 1800s, you can see in this image that the individual masts are not "conical" tapers. They tend to gradually taper starting at the base then more quickly toward the heads. This is because the torque applied to any section of the mast is greater toward the base and least at the head. That torque on a mast also includes the forces applied by the mast(s) above it. So it makes sense that the mast diameter doesn't simply change proportionately with height.

An extreme foreshortened view of the 1891 brigantine Galilee's combined fore topgallant-royal mast, showing the mast taper profiles for each section.

 

Terry