Dovetails

[John OlsenParticipant @johnolsen79199]

Well Peter, it depends whether you want one or not and have the space. They are a useful machine still for the amateur, since the tooling is low cost and speed of production is not usually an issue. It partly depends what sort of work you do…I would rate them as being more useful on stationary engine work than on locos for instance. The reason is that a lot of the larger parts on stationary engines are flat surfaces, which the shaper excels at. At one point I had just the little Unimat lathe and the six inch shaper. You would be surprised how much of a Stuart #1 engine can be done with that combination. Not the flywheel, and not the bore either, but most of the rest can be done. The six inch shaper is actually capable of more than six inches, they later (like 60 years ago) sold the same machine as a seven inch shaper, so it could just manage the box bed of the Stuart. The engine bed and the column were well within its reach.

 

A manual shaper is a great thing if you want to develope muscles like Popeye. If you read the old comics you will see that most people were prepared to go to a lot of trouble to fit a motor to them. Still interesting as a collectors item of course, and useful so long as you don’t have too much metal to take off.

 

To be pedantic, Johns shaper is actually a slotter. Very useful for cutting internal keyways, splines, gears, and the like. You will notice that the rotary table is not an accessory, it is an essential part of the machine.

 

Incidently although shapers are good for doing dovetails with, it would be remiss of me not to mention that it has its moments. The external one (male?) as we see it above is not too bad to do, except that one must remember that the two horizontal surfaces at the left and right should both be exactly the same height, as they are bearing surfaces. Since they will have to be cut with the opposite hand of tool, that is not a trivial task.

 

Then when we do the female part, we have to first rough out a groove with a tool like a parting tool, which has all the same potential problems as parting in the lathe. Then we have to do the two undercuts at each side, preferably keeping the bottom of the hollow the same height all the way across, although this is aesthetic since this is not a bearing surface.

 

Also for all of the actual dovetail cutting, we are feeding the cutter down by turning the handle on the downfeed as it reciprocates back and forth. This is the kind of thing that “health and safety” would hate, although your hand is safe enough up there, just don’t put it anywhere near the workpiece.

 

regards

John

[adyParticipant @ady]

There’s not so many small shapers around compared with small lathes.

It seems to be a bit of a black art/lost art because the tools are the same as with a lathe but need to be ground for shaper work.

With this in mind, and the ability of a shaper to do internal broaching I would have thought they would have been a lot more popular than what they actually are.

 

The saving on buying fancy cutters alone could justify a moderate purchase, shapers usually go for only moderate amounts of money, and tool resharpening is a doddle compared with more complicated and expensive revolving cutters, even a damaged shaper cutter can be reground while a damaged revolving cutter would be ruined.

For internal shapes a trench can be cut with a relatively expensive slot drill and the other 90% of the job can be done with an expendable hss shaper tool.

 

A nice one here went for decent money.

 

I find them quite mesmerising, especially if they are removing serious amounts of metal.

 

This old one runs amazingly quietly and clearly shows the technical action of the cutting tool on each stroke and why the clapper box got its name.

 

Edited By ady on 30/04/2011 09:44:00

[adyParticipant @ady]

While a shaper with a decent stroke could be used for making things like standard cross slide t-slots and dovetails, with some experience a shaper could also give you the opportunity to look at making tapered gib strip dovetail slides, which are a lot more convenient than standard gibs.

[jomacParticipant @jomac]

Some things are sad, my old mate, known him for 50 years. was an inveterate buyer of tools, he had a Hercus lathe (south bend) , virtually unused large, round columb milling machine, power hacksaw, and a 14′ shaper, he also had two, 7 foot high steel cabinets full of tooling and measuring equipment, including a 10′ rotary table which was indexable, with all the extra plates, this he brought just for one job only. He is older than me, and is now getting dementia he had forgotten that Id’e asked him if he wanted to sell the shaper and the mill. Anyway I think he sold his whole workshop as a job lot, so someone got a bargain!!!, his wife did not have any idea what it is now worth which is a shame, because he practically gave it all away. I was thinking of making a shaper, similar to the Gingery aluminium shaper, but at the moment I have not finished making the furnace, (next job), unfortunately down here, in OZ, the scarp metal merchants wont sell to the general public any more so getting scrap ally, brass and bronze is out, so is the shaper!!!! . Unless,??? it is worth while making a small hand shaper/slotter, similar to the plans on the internet, or just stick with the mini mill,

Doing dovetails without a lathe or a mill is a pain in the butt, I know, cause when I used to make snooker cues, I needed to make the brass joints, so I made a lathe, using one of those cheap Chinese double cross slides, and the 2 meter long wood lathe, turned up most of the round pieces, but the dovetails for the cross and compound slides, I fabricated from flat steel and bars, using a welded up jig set at 30/60 degrees, and the large angle grinder mounted on a hardwood bracket, and slid them along a guide, cut the angled fairly closely then bolted them together, used a piece of granite with wet and dry emery paper to get them accurate, They still needed to fine tuned with a file and scraper, which was tedious to say the least, bolted and pinned everthing together, and it worked !!! .(sorry no smilie faces, they stop my posts), Now Iv’e got a good lathe and a small mill, they do make a difference in making IC engines and swarf, Although I did stopped making snooker cues, the Asians make quality cues 1/3 of the price that I paid just for the timber.

Any thoughts on making a small shaper, too broke and mean to buy one though.

John Holloway

[dcostaParticipant @dcosta]

Hello.

I’m building a shaper machine following the book by David Gingery and introducing some modifications of my own.
The shaper machine is not yet able to test cutting with it. There are still a few hours of work to do…
Basically, I lack the building of the table for fixing the material to be cut, the simple mechanism of automatic feed of this same table and the underlying structure that will support the engine. For now, the shaper is mounted on a bench workmate Black & Decker with a temporary motor and it works very strongly and very smoothly.

But for those who might be interested in a machine like this there is an example that can be viewed cutting metal (I think aluminum alloy) at the following URL http://www.youtube.com/watch?v=JZdbNWoySo0. There are some more movies of the same shaper machine. You can look for rgsparber (its builder).

In my album there is a set of photographs dedicated to building my shaper machine that shows some of the steps in its construction almost entirely from solid blocks of aluminum http://www.model-engineer.co.uk/albums/member_album.asp? a = 8270

Best regards

Dias Costa

[John OlsenParticipant @johnolsen79199]

Ady, as per the comments on the utube page, that last shaper is definitely running backwards! He shouldn’t leave the adjusting handle on the end of the shaft while it is going around either, this can lead to nasty surprises. You can see in the first link why you don’t want to get in the way of those chunks of swarf as they come off.

 

There have been designs for shapers using bar stock material. There was a set of castings that came out of Australia a few years back for a modest size of machine. I don’t know if they are still available. If I wanted to make one I would probably make up a set of patterns for myself, but I have enough shapers and enough other projects. Well, I do have a project for a model shaper, to 1/12 scale. It will have a proper quick return mechanism, unlike the Stuart one. It is quite handy having the machine you are modelling right there in the workshop.

 

If you want alloy material for castings, you could try the car wreckers, the stuff they make the wheels out of seems pretty good. They do get wheels with chunks out of them from time to time.

 

I hadn’t thought of trying to make up tapered gibs, that is a good idea. Have to think about it a bit, since it would be important for the taper to match on the female dovetail as well.

 

regards

John

[adyParticipant @ady]

I hadn’t thought of trying to make up tapered gibs, that is a good
idea. Have to think about it a bit, since it would be important for the
taper to match on the female dovetail as well.

 

There’s no taper on the female side, It all happens on the male side.

One side of the male part is tapered, and has a matching tapered gib to make it parallel, the female part slides on as normal.

As you screw in the gib from the rear, it bears on one side of the female dovetail and the tapered side of the male dovetail, eliminating backlash.

You can see the tapered male dovetail in my zero backlash nut photos, on the left hand side.

 

I see what you mean with video 3 btw, oops.

Edited By ady on 01/05/2011 03:14:13

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