DCP’s Blog

22 Articles

Fine WoodWorking

案板 (cutting board)

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老婆抱怨家里的案板都被用坏掉了,让我自己做一个用不坏的。我努努嘴,心想一个案板外面买就10块钱,自己做怎么都不止这个价,何必呢?

在老婆的催促下,做了一个案板交差。心里知道自己做的这个就是比买的案板木头质量好点,厚度厚一点 (一英寸多厚),别的其实都一样。

为啥老婆用的案板总是坏呢?几个原因:

1)老婆总是把案板档砍板(chopping board)来砍排骨。chopping board 和 cutting board 是不可以混用的,因为木纹选择完全不一样。我接下来给老婆要做一个chopping board,专门用来砍排骨。

2)无论是案板还是砍版都不能够放到dish washer里面去洗,尽量的少接触水。

3)cutting board 和chopping board要定期维护。如何维护呢?用油。对人无害的油。常用的案板油是mineral oil + gulf wax. 因为案板太便宜了,我家从来没有人去上油维护。

下面的图片是我做的案板,希望能被老婆蹂躏的旧一点:)

 

Fine WoodWorking

Walnut tray — handcut dovetails with compound angles

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I found myself fall in love with dovetails with compound angles, after watching Chad Stanton’s Youtube video:

Conventional dovetails are those pins and tails jointed at 90deg angles, where the compound angles add additional difficulties on making the dovetails. To my best knowledge, the dovetails with compound angles can only be made by hand cut; there is no jig or machines that can automate joints.

Here are the pictures of the dovetails trays that I made last week.

 

 

Woodworking Technology

家具木料 (二)

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接着聊家具的木料。

从上个世纪的30年代开始,合成木料(engineering wood)开始进入家具市场。这包括我们常常看到的三合板 (plywood),还有MDF (medium density board) 和OSB (Oriented strand board). OSB主要用于盖房子,家具常用plywood和MDF.

engineering wood有几个特点:价格相对便宜,木性均匀(各向同性),尺寸标准化,易于加工。但是也有几个缺点: 材料强度不如硬木;三合板木纹比较单调; 对水非常敏感,一泡就烂。

三合板常常用在cabinet上, 如果厨房橱柜的两个面。 MDF常常用于做桌面, 因为MDF的强度和防水都不够好,桌面的中间层用MDF,然后上下再胶粘一层hardwood, 这样既好看,有省钱。

现在全部用硬木的家具是越来越贵,而且越来越少。以致于高端的家具店把全硬木的家具作为一个广告的卖点,比如:

我自己做的家具完全不用MDF; plywood用的也非常少, 唯一用到Plywood的地方就是柜子的后背,或者抽屉的底面这种不承受太多重量的地方。

下次有时间再聊聊hardwood的木性 – 这是硬木家具的技术精华!

Woodworking Technology

家具木料 (一)

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聊一聊木工家具用的木料。木料分为硬木和软木,软木包括fir, pine等; 硬木包括maple, oak, walnut, cherry, mahogany 等等。硬木适合做家具。

选择合适的木料是做家具最关键的一步。木料的颜色,木纹,硬度, 可加工性,上色性对做家具加工的每一步都有至关重要的影响; 如果从一开始, 木料的选择出现了偏差,后面就非常难以纠正。

北美的木料,最被推崇的是walnut,这也是我最喜欢用的木料。黑咖啡色,硬度适中,非常好上色,比较容易加工;特别是walnut有一种天然的香味,非常难忘!cherry是另外一种好木料,唯一不足是上色比较容易blotch. birch, oak 和maple 都属于中档的木料,颜色和硬度各有不同的特点。

外国进口木料最好的当属mahogany, 也就是我们中国人说的红木。红木具备家具木料所需要的所有优点, 颜色也很大方。而且红木不会被虫蛀,所以以前的大门很多都是用红木。因为红木太适合做家具和盖房子,被砍伐的非常厉害; 亚马逊原始森林的减少被认为和红木的需求有很大的关系;红木在2000年左右被联合国定为珍惜物种,对买卖交易进行限制;现在红木价格非常昂贵。红木的质量跟产地也有关系;最好的当属古巴红木,被古巴定为国宝,禁止出口,市场上是有价无市,买不到。次一级的红木是洪都拉斯红木;然后是东南亚红木。市场上有一种非洲红木,其实不是红木,只是颜色和质地上和红木非常相似,大家都叫它非洲红木。

 

 

Miscellaneous

大烟山之旅 – a old farm

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好久没有更新blog。度过了一个繁忙的夏天。在孩子暑假结束前全家去了一趟大烟山(Great Smoky Mountains). 以前听到过周围朋友无数次的推荐,这次终于得以成行。全家决定搞一个road trip, 开上F150,选择住在山上的cabin。

在大烟山某天,全家参观了一个保留相对完好的farm. 这是一个很老的farm, 没有任何的电力设备和电动工具。让我特别最印象深刻的是farmer 的房子和家具. 他们的房子是就地取材,用山里很粗很长的log, log的两端切出燕尾形状,加强强度。 从木工结构上讲,整个房子就是一个大的dovetail盒子。

家具也是保持的相当完好,明显都是用传统的手动工具做出来的。家具设计没有fancy的细节,风格相对简单明了,以功能为主,很接地气。因为不让靠近,更不许触摸,没法搞清楚家具用的finish.

当地南部的人非常热情地向我介绍用于做房子的木料。1900以前当地的房子大多用chestnut, 直径4‘-5‘英尺的chestnut以前当地非常常见。后来所有的chestnut都感染上了一种fungus (https://en.wikipedia.org/wiki/Chestnut_blight), 存活下来的chestnut都长不高,也长不大,而且这种fungus到现在都没法彻底消除。所以现在在北美再也见不到大的chestnut树了。

选择用F150做road trip 是因为我早都听说great smoky mountains有非常好的做木匠的木料,这么好的机会当然不能放过。回程运了将近300bf的lumber 回了德州。

Fine WoodWorking

Wooden Tray

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Both me and my wife are a bit tired of a tray that is at the entrance to our living room from garage. This tray is used conveniently by us to place the keys, wallets, and cellphones after getting back home. The tray is made of cloth wrapping up a rigid cubic frame (by plastic or metal, I guess).

I decided to make a wooden tray to replace it. A challenge of making a tray is really the compound angles jointing the four sides of a tray: usually, a tray has four sides that are all splayed at an angle (10 degree or less). This splay angle results in the fact that none of the sides of a tray is a standard rectangle and there will be a miter angle on the jointing edge; on top of it, instead of a 45 deg standard bevel, there is a different bevel angle determined by the splay angle. For example,  for a 10 deg splay angle, the bevel angle will be about 44.1deg and the miter angle will be 9.9 deg. All these are called compound angles. To calculate the compound angles, people usually use trigonometric formulas. Fortunately, there are websites doing the calculation and helping lazy people like me. This is a website that I use a lot.

Below are the pictures of the wooden tray that I made. It is made of maple and walnut for the splines. The finish is boiled linseed oil to pop the grain, dewaxed Shellac (1# cut) as a sealcoat, and a water-based top coat.

 

Fine WoodWorking

Wooden box (II)

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在太太的要求下,周末又做了一个木盒子。 盒子的四个面是枫树木(maple),盖子是梨木(pear)。

因为有一年多没有手工切燕尾接头,手有点痒痒,决定手工切燕尾接头。燕尾接头被认为是集强度和美观于一体的接头,好一点的商业家具的抽屉都是这种接头。现代绝大多数的燕尾接头是用电动router 和燕尾夹具做的,这种做法已经相当于机械化了:接头切的好坏取决于机器和夹具本身,而不是木匠的手艺。当然古代家具的燕尾接头都是手工切的,费力费时。在youtube上我们偶尔可以看到木匠比赛手工切燕尾接头:这活儿确实是代表木匠手艺。

这次玩了玩,觉得好久没手工切了,手都有点生疏。还是要庖丁解牛,手熟!

 

Fine WoodWorking

small wooden box (I)

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Through the years, I have accumulated a large number of router bits. However, the router table I built in the shop does not have a drawer or storage space for them; it becomes annoying to spend time looking for a bit when I am in the middle of woodworking. Finally, I got a chance to make a small wooden box for storing them.

The sides of the wooden box are made of red oak; the wood for the box top is pear. I bought the pear lumber from a retired carpenter who fell the pear tree from his backyard. I re-saw the pear lumber into thin boards and book matched them for the top (so it is symmetrical along the grain).

The sides of the box are glued together by 45deg miter joints, with spline to enhance the strength. The spline is made of black walnut for the contrast.

My LOMLwants me to make another one for her after seeing the box; she wants to use it on the desk in her office. This will become my excuse to work in the shop for next weekend:)

Fine WoodWorking

Wooden Picture Frame

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My LOML complained too many drawings and paintings by our kids from their art classes are scattered in the house; some of them are already lost or damaged; she wanted to put them into picture frames and hang on the walls. I thought she can buy wooden frames from arts & crafts stores like Michaels or Hobby Lobby, but she said the sizes of the drawings or paintings are often different from the standard frame sold in the stores. In addition, she does not like those painted frames. So it becomes my task to make wooden frames.

I use white oak for the frames, primarily because oak is inexpensive here. Structure wise, a picture frame is simply built by four 45deg miter joints, with rabbets at all four sides and decorative profiles on the front. But I am always wary of the strength of a glued miter joint, as some of the miter joints of our purchased frames already have cracks, like this one:

I like to use splines at the miter joints to enhance its strength. Here is a frame that I made:

Looking from the front:

Restoration of Vintage Machines

Restoration of Vintage Woodworking Machines (V) – Unloading Machine from a Truck

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It is relatively easy to unload a machine from a trailer; but it could be a challenge to safely  unload a 400lb machine from a truck bed.

There are a few ways of attacking the problem. One is to build a wooden Gantry Crane using 4 by 4 lumber. Below is a picture of the one that I built:

The design of the Gantry Crane is pretty much following the design here: https://www.youtube.com/watch?v=PtPU1pOTLH4

The other method is to use an engine hoist, like the below picture where an engine hoist lifts up a 400 lb Powermatic planer above the truck bed.

After that you back out the truck and lower the planer, as shown below: