Making a Modified SASS - Page 1

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There are other ways a SASS can be modified, these pages show the way I do it, hopefully helpful even if you do it different. I use a 7x12 minilathe and the matching minimill along with assorted accessories. This SASS will hold a pair of Sennheiser MKH-20's
Obtaining SASS parts:
Crown Parts Telephone number: 1-800-342-6939 (as for Parts Department). 

Part Number

Description

Price 2007

D 7078-5

Plastic Housing

$ 153.53

D 7446-4

Foam Baffle

$ 62.50

D 7302J8

Windscreen (lycra and foam, slips over entire SASS)

$ 51.81

D 7097R6

Swivel Clamp (provides standard 27X5/8 thread mount)

$ 46.29

M 44158-0

Knob (For Swivel Clamp)

$ 8.11

A 10101-21

(2) Mylar Washers (For Swivel Clamp)

$ 0.69ea

D 7092-6

Adapter (Swivel Clamp to Hand Grip, also provides 1/4" and 3/8" tripod mount)

$ 18.00

M 20755J0

Hand Grip

$ 47.09
That's all you need from Crown. You end up with housing, baffle, and windscreen, with an adjustable tripod mount assembly and hand grip. The Plastic Housing and Foam Baffle are the essential components if you wish to build your own windscreen and mount.

Start with a length of Delrin rod, 1 1/2" in diameter. You need enough length for two microphone supports plus waste for chucking in the lathe. Minimum length for the supports with a 3/16" back plate is about 3 3/8". It will take another couple inches for chucking and tool clearance, so you need at least 9" of the rod.
Chuck the rod and use a tailstock. Check runout with a dial indicator, it only needs to be close so you don't waste too much material. Face the outside of the rod for the length that will become the two supports. This will be the final finish on the outside of these supports, so make it nice, without cutting the diameter much. Facing the outside in this way insures that the diameter of the two supports will be the same. In this case the final diameter was a little over 1.47". After facing use a cutoff to cut the two supports to length, allow a little extra for finishing. You have to do this slow, the rod will flex with side loading.

Now you have two support blanks. What follows will be about making one support, repeat them with the second support. Chuck one up in the lathe, remember to pad the outside to keep the chuck from marring the surface, in this case with some brass shim. Since you are now not using a tailstock, check runout each time you rechuck a piece, you want everthing to be perpendicular when done.

Face each end of the blank. Also helps to smooth the edge with a file against the turning plastic. You will be working around that a lot. Adjust the length of the two blanks to match.

Now that we have two matched rods we must bore them out to hold the mics. I prefer making the initial bore with a milling cutter, in this case a long shank 3/8". This is not quite long enough, so is finished with a twist drill.

Switch to a boring bar and enlarge the hole to fit the MKH-20. As you approach the size, measure every pass. My MKH-20 here measures 0.9920". You want to make the hole somewhat larger than that.

MKH-20 meets support for the first time, a tight fit. Enlarge hole somewhat more to allow play, the o-rings will support the mic. I usually enlarge it enough that the two screws at the connector end of the MKH-20 will just slip through.

Now begin fitting the O-rings. The hand ground tool and one of the silicon O-rings. Size is 1"x 1 3/16"x 3/32".
I obtain these from: http://www.allorings.com/
In their system it's a size -120 O-ring, Description 70D Orange Silicone O-rings.
O-ring groove partially cut in back end.

Finished back end. Enlarge the groove until first the O-ring drops into the groove with no kinks. Now check the MKH-20 against the O-ring, it should not slip through. In small increments continue enlarging the groove until the MKH-20 first slips through and then slips in and is held by the O-ring with the appropriate amount of grip, enough to keep it from slipping while open enough you can remove it when you want to. Note on the completed back end a bevel on the outside. I think it looks nicer with that. While the back end O-ring is about 1/4" in the tube, when cutting the front end, cut the groove just inside the end. Finished front end, after finishing with the O-ring reface the front end which may have deformed slightly while cutting the groove. And smooth the edges making sure there are no hanging threads of plastic.

Completed support ready for mounting in the housing with a MKH-20 in place. Complete the second one the same way.

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November 9, 2005
Mail To: wwknapp@mindspring.com
Copyright: Walter W. Knapp