DobSTUFF Kit Assembly

ASSEMBLE THE KIT: This "assembly page" is a work in progress. I've been asked by a number of my "kit buyers" for some suggestions putting the kit and scope together. So, using my 15" Discovery make over as an example, I've begun to put these pictures and descriptions together. There will be more to follow. In the following days, I'll add pictures showing how to put the inserts into the strut (tube) ends, cutting the tubing and figuring the proper length of the strut.

If you have any questions, or see anything I haven't covered, please let me know and I'll add that information. Simply email me at densteele@dobstuff.com and I'll follow up and quickly as I can.

SOME SUGGESTIONS:

== FINISHING THE WOOD: There are couple of very nice varnishes, either the brush or spray kind. I like to use the Varathane "spray" varnish. It's available in gloss or semi-gloss. Use #320 sandpaper to prepare the wood, sanding with the grain. After the coat of varnish dries, polish lightly with the sandpaper and spray again. Make sure you remove all the "dust" from sanding. A shammy works nicely. I suggest 4 coats, paying special attention to the "edge" of the wood, as the varnish absorbs into the wood easily. Spray or brush varnish the edges 7 or 8 times.

== STAINS: Two of my "kit builders" have used stains. The Birch ply stains very nicely. Many of the stains have the varnish built in. Again, multiple coats are a good idea, sanding between coats with #320 sandpaper. If you'd like, I can send you a piece of wood to "test" the color and finish of the stain.

== ASSEMBLY: I like to assemble the scope with "wood screws" only until everything looks right. Be sure to drill a pilot hole slightly smaller than the wood screw. Since the wood is 3/4" thick, I like to use 1 1/4 inch wood screws. A number 4 or 5 Phillips flathead wood screw works fine. If you have a variable speed drill with a Phillips screw driver, it'll be easier to complete the job. The nice thing about using Phillips screws is that the screw driver stays in place. Be sure to use the right screw driver bit, otherwise you'll damage the screw head, making the screw difficult to remove later.

== GLUE: Once the scope is assembled to your satisfaction, you may wish to disassemble the rocker box and reassemble with screws and "glue". I like to use Elmer's white glue. It dries fairly quickly is a "clear in color". You may wish to use the scope for a while before gluing. No harm with that.

== EBONY STAR AND ALTITUDE BEARINGS: Affixing the Ebony Star (ES) to the altitude bearings is easy to do. Again, be sure you have varnished the edge of the altitude bearings to seal the wood. Otherwise the wood absorbs the contact cement and the ES won't bond to the wood very well. Varathane sells a wood "sealer", but I find a few coats of varnish does the same job. Varnish the entire altitude bearing before putting on the ES. If the contact cement drips or runs a bit, it'll wipe off easily. Otherwise, it'll be absorbed into the wood and discolor it slightly.

== SETTING THE LENGTH OF THE STRUTS: Once you're ready, it's time to set the correct length of the struts and cut them. After you have the mirror/cell, secondary/spider and focuser in place, you'll have the dimensions needed to use a neat little software program called "Newt". You can download Newt here. Newt will get you in the "ball park", but sometimes the actual strut length is a bit different than the program indicates. I like to actually use the telescope "under the stars" before cutting the strut length. How?? I use adjustable struts, but I don't think that's practical for everyone. Take a look at item #15 below. Fred, in Bloomington, Indiana, used wood dowels to test the length of the struts and made sure all his eyepieces came to focus. Start out a bit "longer" and slowly down them shorter and shorter until everything works correctly. You don't need to worry about collimation, just get a star image into the field of view, focus all of your eyepieces and you're all set.

== SETTING THE LENGTH OF THE STRUTS 2: Here's an easy procedure for measuring the strut length with a tape measure. Click here.

== MOUNT YOUR MIRROR TO YOUR MIRROR WITH SILICONE. For a discussion of this subject, pictures and instructions, click here.

I hope the pictures and descriptions that follow are helpful. They are in no particular order .

Thanks, Dennis

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1) The sides of the rocker box are affixed to the front cross board. I suggest using pilot holes and then flat-head wood screws, to assemble the entire scope. Once it's complete, you can use glue later. I use Elmer's White Glue

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7) You can use a flat-head bolt (left) or a knob (with threaded stud) to attach the top ring to the aluminum struts. I like the knob as it makes for a nice "tool-less" assembly of the scope. I use a "nylon lock bolt" on the backside so the flathead or knob becomes a "captive" bolt. You can turn but wont fall out and disappear in the dark. Thread size is 1/4-20..

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2) The sides of the rocker box are affixed to the rear cross board. Use pilot holes, wood screws and glue later.

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8) Here are two different mounting brackets for the spider. The left example is for the "Destiny" curved vane spider. The one on the right is for "Protostar" or any other traditionally mounted spider. I make the brackets from aluminum "angle iron". You can use 1" or 1.5" angle, depending on the spider to be mounted. You can buy this material by the foot at Orchard Supply and Hardware.

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3) The top of the altitude bearing is affixed to one of the side struts with a clamp. A carriage bolt is used with a wing nut or threaded knob. I include two of these clamps. You'll need to shorten them to fit. I use a table sander and work slowly.

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9) I use aluminum "angle iron" for mounting the focuser. The material is 4" or 4.5" wide and 4.5" long. I cut down the side that mounts onto the ring. If you use a standard spider, one that is adjustable along the optical axis, you don't need to worry about measurements too much. Just center the focuser. For Protostar, take care to measure properly as the secondary doesn't adjust up and down the optical axis. For Destiny, you'll need to measure as well, but Destiny's secondary is adjustable up and down the optical axis, although not very much. Measure twice, cut once. The hole for the focuser tube is cut with a standard "hole saw" on the drill press.

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4) Two items to notice here. First the "side board" of the mirror box. I affix the board at the top and bottom with wood screws (use pilot holes). Second, the altitude bearing is drilled through the side board. Be sure to set the altitude bearing at 45 degrees. I first assemble the entire optical tube assembly and determine the balance point. Use the "center" hole in the bearing at the balance point.

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10) Here's some chemicals you might find helpful. Left to right: a) Flat black spray paint for touching up the spider mount or under the focuser mount, b) Weldwood contact cement. Use this for mounting the Ebony Star to the altitude bearings, c) 3M Spray adhesive. I use this to affix the laminate to the bottom of the rocker box (contact cement works fine too), d) Brush on spar varnish, e) Varathane spray varnish, f) Lemon oil "Pledge" furniture polish. Polishing the rocker box laminate, the Ebony Star and the Teflon reduces stickstion, and g) Elmer white glue. This glue dries quickly and is clear in color.

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5) Attaching the Teflon bearing to the ground board can be accomplished in a couple of different ways. a) Drill and countersink a couple of flat-head wood screws, or b) put a short "pin" of 1/4" doweling into the base and simply set the bearing over the pin. Make sure the "pin" is shorter than the thickness of the Teflon so the wood pin doesn't rub on the rocker box laminate. Once the rocker box is placed over the ground board, the Teflon is held in place and won't move. The diameter of the Teflon here is 2.5 or 3 inches and is cut with a hole saw.

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11) Some hardware: I use 1/4-20 thread size for all my kits. a) Threaded "through hole" knob, b) Threaded "stud" knob, c) tube insert, and d) Nail-on "chair glides", 7/8" diameter.

6A) Mounting the altitude bearing "Teflon" is easy. Use 1" long Teflon bearings for all of my telescopes. Simply drill a hole in the center, and countersink a 1/2" long wood screw. I place the Teflon at about 90-degrees with respect to the center of the altitude bearing. I

6B) A fender washer is included in the kit that is the same size, or just a bit larger, than the strut diameter. These are placed where the strut affixes to the mirror board. As the strut is tightened onto the mirror board, the washer keep the strut from digging into the wood.

12) I cut and install the baffle as shown. Each installation is a bit different, depending on the size of scope and whether you're using a 3 or 4 vane spider. Making a "pattern" with thin cardboard (a manila file folder works well), is a good idea. It's easier making a pattern over again than finding another piece of Kydex.

As you look into the focuser, fully "infocused" and without an eyepiece, you want to see the baffle as you move your eye around from edge to edge, top to bottom and side to side. The baffle can't be too big, but it can be too small.

Once the Kydex is cut (I include one of these in the kit), you can affix the baffle to the top ring in one of two ways: a) Use a wood or sheet metal screw directly into the edge of the top ring, or b) I use a threaded insert and knob. These are readily available from Orchard Supply

See item descriptions #13, to the right.

13) TThese parts are included with each kit. Here's a brief description:

A)	Rubber tips. These are used on the rear of the mirror box as "feet" to stand the assemble on during scope storage, assembly and disassembly.
B)	3 Carriage bolts and tube inserts. Used through the mirror board in conjunction with the short struts that make up the mirror box. The flathead bolts (fig F) are used through the center ring to complete the mirror box assembly.
C)	Tube Inserts: Used on the ends of the main OTA struts. Use on the top or bottom.
D)	Tube Inserts: Same as C.
E)	These are the feet that are used on the bottom of the ground board. I have marked the ground board for location during assembly.
F)	Flat head bolts during mirror box assembly. See item B.
G)	Carriage bolts, washers and lock nuts. These are used through the mirror board to affix the main struts during OTA assembly. The carriage board is inserted up, pointing toward the spider and tapped with a hammer until flush. The washer and lock nut are put on to the top, tightly, making them a "captive" assembly. Finally, the main strut is inserts through the top ring of the mirror box and screwed "onto" the bolt.
H)	Threaded knobs with studs. These are inserted through the top ring, facing the primary mirror. The washers and lock nuts are installed so that the knobs are "captive". These will affix the tip ring to the struts without the use of tools.
I)	Spider brackets. See item 8 above.
J)	Teflon bearings for the rocker box. See item 6 above.

	NOTE: I include the azimuth Teflon and laminate for the ground board. They are installed at the time I ship the kit. You'll only need to disassemble the two piece, stain and varnish as desired, and glue the laminate to the bottom of the rocker box. See item 5 above for some detail.

15) Here's a good example of a kit assembly. Fred, located in Bloomington, Indiana, has put together the mirror box and top ring and then used wood dowels and bungee cords to keep everything together. He'll adjust the length of the dowels (the struts) as needed and then cut the aluminum. Just make sure you've made the wood dowels a bit "longer" than needed. The best way to test the length of the struts is by actually using the OTA under the stars and bring your eyepieces to a focus.

Calculate the length of the struts with this simple procedure. Click here.

For more information about your requirements:
--Dennis Steele
--Tel: 650-315-6578 (anytime)
--Email: densteele@dobstuff.com