getting ready for drawer making

Re: getting ready for drawer making

Good luck!  A piston fit is all fine and dandy, but the humidity in your house better never change.  I did that one time with an end table I made for my daughter.  I made it in the winter and the next summer she brought it to me to get the drawer open.  It took a crow bar.

Wrong time of year for a piston fit

Come spring time a piston fit drawer will likely be stuck.

Complete tutorial on making and fitting drawers

Hi Eliot

I think the world of Rob Cosman as a teacher. He is methodical, addresses important areas, looks at the finer detail ... well worth watching. I have learned much from him (and he has used some of my techniques).

When I built my underbench cabinet, it was not just a WIP for the forum, but a documentation of the steps to fine drawer-making, as I do it. The only area which I did not go into was the use of slips typical to fine drawers. Instead I have included slips to reinforce work drawers.

I hope that others find this a useful reference source. Links below.

There are several chapters, starting with preparing the drawer blades and the drawer case. It needs to be emphasised that "piston fit" drawers need a square and true case. Sometimes the build accuracy is not enough, as wood moves, and a little fine tuning is recommended.  Before the Drawers

Then we move on to the drawer parts. Drawer parts before dovetailing the drawers

Constructing the drawers is presented over three articles:

Dovetailing for Blood!

Dovetailing for Blood! …Part 2

Dovetailing for Blood! …Part 3

This is now followed by Drawer Bottoms and Slips

Completed drawers from the back of the (mitred through dovetailed) case ...

From the front:

Regards from Perth

Derek

Re: Complete tutorial on making and fitting drawers

Thank You Derek.

Metrics for drawer fitting

Any chance I get I study drawers in antique furniture that has survived for a century or two.  I note how smoothy they work and what sort of clearance they have. 

It is straightforward to predict what the drawer will do in response to seasonal changes.  Not so with the case.  To test drawer fits, I like to set my case pieces in a high humidity environment for a couple of weeks before delivery.  It is not uncommon that I have to do an adjustment. 

Sometimes to achieve a drawer that will work properly over the seasons the clearance at low humidity will lead to gaps in the front that are not attractively small.  However, the only time this annoyance will be noticed is by the maker before delivery. 

Re: Complete tutorial on making and fitting drawers

Derek,  This is excellent.  Thanks.

Re: getting ready for drawer making

That is a bit worrisome. Do you think I'll be all right if I allow a bit of room for expansion across the grain? My understanding is that it shouldn't be a problem along the grain.

Re: Metrics for drawer fitting

My thought is that it's the drawers that I have to worry more about because the case is plywood. Am I missing something?

Re: Wrong time of year for a piston fit

As I already asked, can't I just leave a little bit of room for cross grain expansion?

Re: Wrong time of year for a piston fit

Yes. Leave some room for expansion on the cross grain sides. It's really a guess.�

Re: getting ready for drawer making

Wood Handbook (https://www.kopperspc.com/pdfs/wood-handbook.pdf) chapter 4 gives you an explanation and a starting point for estimating shrinkage/expansion for a variety of woods.�

Re: Wrong time of year for a piston fit

Hi Eliot,

It will be guesswork to determine the clearance you need.

This would be a good week to make a reference board marking the date and measured width to check later in the year. Quarter sawn pine will be very stable, make boards in your other preferred materials to see the difference.

Re: Wrong time of year for a piston fit

Hi Eliot,

What everyone says is true.  But this piece is going to be in your house.  It’s not a gift to someone else.  You’ll see it every day and can test the drawers everyday.  

So there’s really nothing to get excited about.  Just make the drawers, and fit them to suit how you’re feeling that day.  As the humidity rises seasonally, you can scrape, plane, sand as required to keep them moving.  The whole process will be a good learning experience that teaches you about drawer movement in your home.

Wiley

Good points.

Ensuring all is straight and square inside and outside the drawer is important, and using quarter sawn boards for the drawer sides will also minimise lateral movement. It is lateral movement that is all-important. Just leave space for vertical expansion. Ensure that the wood you use has acclimatised and starts off stable.

I do not think of "piston fit" as tight fitting, but as fitting with the closest tolerances one can achieve without binding anywhere. Too loose and the drawer can be vulnerable for racking.

Drawers that are wider than deep will be most vulnerable to rack. Best drawer design has the depth longer than the width.

Regards from Perth

Derek

Sure, but you won't get the air pumping out the front

There tables greatly overestimate changes, mostly useless

When it comes to building furniture the only thing these tables are good for is to compare the stability of different species and to compare radial and tangential shrinkage for different species.  Large differences between tangential and radial shrinkage lead to defects during drying, something you have discovered if you try drying many of the "fruit" woods- plum, apple, etc.  .

To understand why the absolute values in the tables are useless it helps to know where the numbers came from.  Numerous test specimens were prepare from each species. These were dried from their "green" state to zero percent moisture.  The average shrinkage reported in the table is the average shrinkage from about 30% moisture content to zero, averaged again over the number of test pieces.  The test pieces varied about 30%, the shrinkage from 30% to 0% is not linear and KD wood was found to not respond to humidity changes as much as air dried wood.  The values usually report responses to humidity changes greater than what will be observed in furniture.  Or, misfortune will result in using a piece of wood unusually unstable for that species. 

Build much furniture with drawers and the folly of "piston fit" drawers will become apparent. Some aspects of furniture building lead to appearance or performance differences in the customers hands.   A "piston fit" , as it is described, is not essential for a drawer that works well.  Striving for a "piston fit" is a fools errand that will only lead to frustration without benefit for someone learning to put drawers into a case. Don't take my word for it.  Bring up the subject with any shop putting drawered product out the door to customers. 

Re: Wrong time of year for a piston fit--Wrong!

Here on the Left Coast (US Pacific) winter and spring are our highest humidity seasons. Most woodworkers are disagreeably in the "Wrong Season/Time Standard" in our thinking. 

Then there is the conundrum of air-dry and kiln-dry; more beetle-juice when drying is incomplete or haphazard. 

Or, you can have the most exasperating reactions with wood that refuses to stay in the shape it's prepared for. I have turned a Western Maple guitar body of 5/4 thickness into the same cup shape of 3/4 thickness after two years of several flattenings. This wood is pretty but never going into a critical structural location.

So, I guess a piston fit can be considered a gloat in some circles. Just know, or make sure, it can be "fixed" later. I always thought corrections and repairs were most important in woodwork. At least that is what I find myself doing the most.

Re: Wrong time of year for a piston fit

Thank you,Wiley! What you say here is exactly how I am thinking. For me, at 82, retired for many years, and with nothing much else to bother me, woodworking is something that is challenging and gives me a great deal of pleasure. (Not only that, but I manage to stay out of my wife's hair most of the day!) So I am not worried about getting product out the door. If a drawer binds up latter, as you suggest, I'll just take out my trusty Veritas DX60 rabot de coupe and plane it back a smidgen.

I admit that, like many of us here, I am somewhat concerned about efficiency, frugality, etc. And I don't like screwing up! But for the most part it's all about doing good work and having fun. My big moments come when I show my grandchildren some decent work and hope that they take it to heart when doing what they enjoy.

Re: Wrong time of year for a piston fit--Wrong!

I'm a woodturner more than anything, and I make piston-fit box lids all of the time.  Even after roughing out the box and letting it acclimate and "relax", then turning it some more and letting it acclimate, the perfect suction-fit lid will eventually oval just a little.   

I live in San Diego, about 8 miles from the coast.  I once made a box for a friend who lived within a mile.  He brought the box back to me because the lid would not fit.  When I got it back to my shop - perfect fit.  I gave it back - lid wouldn't fit.  I took it back again to my shop (perfect fit) and surmised that the difference in humidity between his location and mine was the difference.

I made two cocobolo boxes for my in-laws about 20 years ago.  They recently passed and I received the boxes back.  Both boxes are very slightly oval.  There is a perfect fit when the grain aligns and a snug fit when the lid is rotated 90 degrees.

Of course, wood species, finish, etc. all play into the final result.  You flat-builders have a much bigger set of variables to manage.  Good luck.

Derek and Rob Cosman method

I'm using Derek's blue tape and Cosman's offset/marking saw method to transfer the tail cuts to the pin board. This is for one of the back corners of the drawer. I measured the dovetail saw thickness and used a corresponding feeler gauge to offset the tailboard when making these cuts. I made a little saw for this purpose from a small piece of a band saw blade. I'm feeling a little guilty because I learn a lot form Cosman but don't buy things from him. (I'm certainly not going to buy an offset block, and it's easy enough to make a little saw of the right thickness.)

I should probably sign up for something on his site.

Re: Wrong time of year for a piston fit--Wrong!

I turn more or less perfect fit boxes all the time. I really don't have much trouble about them sticking. Sometimes , I suppose. The idea is to remove an ever-so-little bit  (hard to describe I admit). But they almost NEVER go oval. I'm presuming that you turn into end grain; then it  really shouldn't ever go oval. And I always use very dry wood.

chopping out the pins

Starting to cut the pin board. I learned to make and use those bench hooks from a Roy Underhill video. Remenber : " That's not a knife, THIS is a knife!" Well, THIS is a bench hook!

Re: chopping out the pins

Re: Good points.

Uh,uh I'm in trouble! I usually follow everything you say. But if I did in this instance, I would have to make sixteen drawers instead of eight, which already seems to be a lot. Why? because my drawers, at about 24 in. wide by 17 in. deep, are indeed wider than they are deep. And it's not too late: I could add vertical spacers and make 16 drawers that are deeper than they are wide. I don't think I have the stamina for 16 --even though I am enjoying myself.