May 31, 2015

Two New 50 mm Linear Motion Lead Screw Macro Rails from Hejnar PHOTO

Hejnar PHOTO MS4-100-2 Linear Motion Lead Screw Macro Rail
Further to the release of the New Linear Motion Lead Screw 25 mm Macro Rail from Hejnar PHOTO just last month, a couple of new Linear motion Macro rails were added to the family, this time with a 50 mm drive.
The design concept is exactly the same with the MS4-200-1, falling between the older MS3_8 lead scew design and the and the high precision MS4 with Micrometric Head.

But beside the double length the new MS4-20-2 has a coarser thus faster 20 TPI lead screw, while the MS4-100-2 maintains the 100 TPI extra fine lead screw.
A Precision Lead Screw with a 100 TPI extra fine movement requires one 100 rotations of the screw in order to move 1" which is snail slow.

Converted into the metric system 20 TPI translate into 0.127 mm and 100 TPI translate into 0.0254 mm movement per rotation of the knob.

The Rail structure

Manufacturer Specification:
Models:MS4-20-2 and MS4-100-2
Length:187,96 mm (7.4")
Total length set at 25 mm:228,6 mm (9")
Width:55 mm (2.18")
Heigth (Thickness):63.5mm (2.5") with F72b QR clamp
Weight:760 gr ( 1 lbs 11 oz)
Materials:Precision C.N.C. machined 6061-T6 Aluminium,
Black hard coat anodized,
Stainless Steel and
Wear- and Water-Resistant Delrin® Acetal Resin (slider)
Hardware:Stainless Steel
Made in:U.S.A.

You need to look close enough so as to discriminate between the two siblings, since there is no difference other than the lead screw thread.
Both the MS4-20-2 and the MS4-20-2 share exactly the same parts with their MS4 siblings. The rail, the base and moving structure and the clamp are made from Black hard coat anodized Aluminium. While the slider bars and the lead screw adjustment mechanism are made from Stainless Steel and Wear & Water-Resistant Delrin® Acetal Resin (see Polyoxymethylene).

Hejnar PHOTO MS4-20-2 Macro Rail - Top view
Lookin closer on the lead screw of the Hejnar PHOTO MS4-20-2 Macro Rail, the coarse thread is obviously the only difference. 
Hejnar PHOTO MS4-100-2 Macro Rail - Top view
On the other hand the threads on the lead screw of the Hejnar PHOTO MS4-100-2 are so fine tha one has to look really close. Something else that has been added to the MS4 lead screw rails since their introduction last month is a quite large in diameter knurled thumb wheel, which facilitates turning the screw with less effort and more precision.  

Together with Mitutoyo Micrometer Heads of the original MS4 Macro Rails, in the name of simplicity and cost reduction, the micrometric scale is also lost unfortunately.

The Quick Release Clamp
Similarities continue, since the slider is equipped with the Hejnar Photo F72b 2.375" (6 cm) long Arca Swiss® compatible Quick Release clamp, which sports an embedded bubble level in one of the safety relief grooves. (b at the end of the model name stands for long black knob).

Hejnar PHOTO MS4-100-2 Macro Rail - F72b QR clamp closeup
The clamp is retained on the slider by a 1/4"-20 flat head screw, which can be easily loosened in order to reveal the relevant threaded hole and the alignment dowel pins.
As all Hejnar PHOTO clamps, F72b has corresponding 5mm holes at its bottom for the proper alignment and reorientation on compatible Hejnar rails or clamps.
Hejnar PHOTO MS4-20-2 Macro Rail - F72b QR clamp reorientation
Just by relocating the dowel pins, the screw knob of the quick release clamp can be reoriented by 90 degrees, at any four positions suitable to the users needs. Then the center 1/4"-20 mounting screw needs to be tightened again securing it in place.
Hejnar PHOTO MS4-100-2 Macro Rail - bottom view
The macro stage is equipped with an Arca Swiss® compatible dovetail at the bottom, so it can be used with any head equipped with an Arca compatible clamp. Despite its longer size, there are still M3 safety stop screws at both ends and a threaded center hole, on the brace in the middle of the rail, for direct mounting on a tripod.

Same as all the members of the MS3 and MS4 families of macro rails, when the rail is mounted on a Tripod Head equipped with an Arca-Swiss® compatible clamp, the camera to subject distance can be roughly adjusted by moving the rail dovetail within the clamp limits and further engage into the process of a fore-aft extra-fine adjustments using the lead screw.

The lead screw fine adjustment is a cost effective alternative to micrometers when position readout is not a requirement.

According to Hejnar PHOTO specs, the MS4 family of Lead Screw or Micrometer macro rails may operate in vertical orientation (perpendicular to the ground) with a load up to 10 lb (4,53 kg), while in horizontal orientation (parallel to the ground) the load may be increased up to 15 lb (6,80 kg).

The choice of materials, manufacturing quality, extra fine adjustment and last but not least, Arca Swiss® compatibility make this Linear Focusing rail really outstanding.
Both the base rail dovetail and the QR Clamp are compatible with Kirk®, R.R.S.®, Arca-Swiss®, and almost all other Arca-Swiss style Quick release clamps and plates respectfully.

I hope you found the information useful, thank you for viewing.
All Photos used by permission: ©2015 Chris Hejnar / Hejnar PHOTO

Price & Availability:
Current price for the MS4-20-2 is US$ 399.00 and for the MS4-100-2 is US$ 360.00 (+Shipping where applicable). Both Lead Screw Macro Rails are available from the Hejnar Photo online Store.

If you are interested in the product do check the Recommended Sellers page for a valid Hejnar Photo discount coupon before ordering.

Regarding the awkward price differences between the rails, I have already got an answer from Hejnar Photo stating that high precision 1/4-20 lead screws are costlier to produce than 1/4-100 lead screws independent of size.

Referenced Articles:
New Linear Motion Lead Screw 25 mm Macro Rail from Hejnar PHOTO

Relevant Articles:
New Hejnar PHOTO Linear Motion Micrometer Macro / Micro Rail
New 50mm Linear Motion Micrometer Macro / Micro Rail from Hejnar PHOTO
Hejnar PHOTO MS-3_8 Linear Motion Macro Focusing Stage Review

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