Mount 8-20 spindle assemblies on a common rail at 60-80 mm centres, which makes the frame 480-1,600 mm long, put the roving creel behind the drafting rollers and the drive at one end, and make the pitch larger than the flyer swing so neighbours never touch. The rail and the roller line must stay straight under load, because every spindle is only as good as its alignment to the rollers.
Part of Spinning Frame
How spindles, rollers, creel and drive are arranged along a frame so that all spindles share one drive and can be reached for service.
A Frame Is A Row With The Rollers Behind And The Drive At One End
The overview’s layout: all spindle assemblies are mounted on a common rail; the drafting rollers are common long shafts spanning the full width; the bottom roller shafts are driven by gears from the main drive; each spindle has its own bobbin and flyer; and a creel at the back holds the roving bobbins. Spindle spacing is 60-80 mm centre to centre, compact enough for efficient drive and wide enough for bobbin removal.
From front to back the yarn path runs: creel (roving bobbin) → back rollers → middle rollers → front rollers → flyer eye → bobbin. The operator stands at the front, where the flyers and bobbins are, and the creel is filled from behind or above.
Pitch Is Set By What Must Pass Between Neighbours
The flyer swings through a circle of its own, the bobbin sits inside it, and a full bobbin has to be lifted out. Take the assumed bobbin of 25 mm barrel and 45 mm full diameter used in this tree (Bobbin and Whorl). The flyer arms must clear 45 mm, say 50 mm inside, so the swing is at least 55 mm. At the overview’s tightest pitch of 60 mm that leaves 60 − 55 = 5 mm between neighbouring swings; at 80 mm, 25 mm. A tight pitch saves rail and belt but leaves no room for a hand, a guard or a bent flyer. These clearances are derived from assumed dimensions; fix the pitch from your own flyer.
Rail length follows: 8 spindles × 60 mm = 480 mm to 20 spindles × 80 mm = 1,600 mm. The longer end runs into the sag limit of the roller shafts (Fluted Bottom Rollers).
What You Need
- A rigid rail and frame, of timber or iron, that does not twist (Woodworking, Joinery Techniques).
- Roller bearings in slotted blocks so gauge can be adjusted.
- A gear train at one end to drive the three roller shafts.
- A creel with a free-turning peg for each roving bobbin.
- Guards for flyers and the drive.
Method: Laying Out A Frame
Step 1: Fix the pitch from the flyer swing plus a clear margin for guards and hands.
Step 2: Fix the rail length and check the roller sag at that length.
Step 3: Place the rollers parallel to the rail, and each spindle centre on the line of its roller boss.
Step 4: Place the creel so each roving drops straight to its back roller without a sideways pull.
Step 5: Put the drive at one end, in a guarded gear case, with the belt shifter and a clear stop point within reach of the operator (Drive System).
Worked Example
A frame for 12 spindles at 70 mm pitch is 12 × 70 = 840 mm long. With the bottom roller sag at 15 N/cm over 0.84 m, the 25 mm shaft sags about 5 × 1,500 × 0.84⁴ ÷ (384 × 200 × 10⁹ × 1.92 × 10⁻⁸) = 3,734 ÷ 1.47 × 10⁶ = 2.5 mm, too much, so put a bearing at the middle: each half is 0.42 m and the sag falls by a factor of (0.5)⁴ = 1/16 to 0.16 mm.
Common Mistakes
- Pitch from the bobbin alone, forgetting the flyer swing.
- A frame built before the roller sag is checked.
- No access to the middle spindles in a long frame.
- Creel pegs that bind, which drag the roving.
Safety
Everything along the row is within reach of the operator, and the stop is not
Hair, sleeves and fingers can be caught by any of the 8-20 flyers or the roller gears at the end. Fit guards, keep a clear aisle, and place the stop (belt shifter or rope trip) where the operator can reach it without reaching past a flyer. The total hazard and who can reach the stop are set out in Drive System.
What’s Next
- Learn next: Drive System — belt, tin roller and gears for the whole row
- Combine with: Doffing — the space needed for bobbin change