How Do I Use the Shrinking / Stretching Machine?
(Words and Photos: Martin Thaddeus, Practical Classics Magazine, October 2008 issue)
1. STRETCHING JAWS IN DETAIL
The Frost stretching/ shrinking machine is a clamping device which, under the influence of the lever, will squeeze whichever jaws are mounted in it. The jaws can be swapped for different jobs. A bespoke stand is available, but it’s easy enough to bolt the machine body to a bench or simply to hold it in a vice.
Shown here are the stretching jaws which, when compressed, will grip and pull the metal apart. The actual area that is stretched and the degree of stretching are pretty small for any given stroke of the lever. So the way we control the curvature of the work-piece is a matter of placing multiple stretches where they will be most effective.
2. SHRINKER JAWS IN DETAIL
Shrinking with this device uses the same method as stretching, but with different jaws fitted – swapping jaws takes seconds. It’s certainly more elegant than doing the job by hand, and less skilful, but what counts is the result – usually pretty neat.
The scope for what can be done with this machine is governed by the size of its jaws. A range of larger machines is available with deeper throats.
3. PLACE THE WORK-PIECE
The section of the jaws where the actual shrinking or stretching process takes place is slightly off-centre, so take care to place the workpiece where you need the effect to occur. Larger panels would benefit from another pair of hands.
4. START LEVERING
The lever needs a bit of wellie to really make it work initially. It’s almost worth taking on an apprentice for this part. You will soon find that keeping the work slightly away from the machine allows it to curve more easily. Excellent fun.
5. MOVE ALONG
As with the manual techniques, move the work along and repeat the process until the desired curve is produced. Once acquainted with this machine, it does the business pretty quickly, and it is much neater than the hammer method.
6. STRETCHING COMPLETE
The results from the stretching process using the Frost machine are impressive. The new edge has an even thickness which would allow for easy spot- or MIG-welding without a high risk of burning through. With the hammer technique, hardening and thinning are not uncommon, and this in turn can lead to a few minor problems.
7. SHRINKER COMPLETE
The result is a neat job, with even thickness and no obvious lumps and bumps. The shrinking/stretching machine works on a different principle to the old fashioned method of cold-shrinking with hammers, but the results are favourable.
Shrinker / Stretcher Available at Frost.co.uk
The Shrinker / Stretcher tested by Practical Classics!
Without a doubt one of the most versatile sheet metal working tools you could hope to find. The Shrinker/Stretcher will quickly and easily pull shape into either steel up to 1.2mm [18g] or aluminium up to 2mm [14g]. Use it to fabricate or repair panels anywhere on your car but especially those awkward areas around headlights, around the edges of window frames, door edges, rain channels, wheel arch rims etc.
With the shrinker /stretcher you don’t need to cut-and-weld in order to create curves in sections – simply shrink or stretch the metal into smooth even curvatures in a fraction of the time.
The Shrinker Stretcher with a stand!
The Shrinker / Stretcher Set Stand, supports the weight of your shrinker /stretcher for repairs at height. Height of stand is adjustable from 70cm to 95cm to take a shrinker stretcher combo wih a holder mounting on the pillar for alternate jaws.
The Complete Shrinker / Stretcher Stand Set, includes two separate pedal driven shaping units, one to stretch, one to shrink, mounted on the stand.
The Heavy Duty Shrinker Stretcher with Stand with a max capacity of 16 gauge mild steel and 14 gauge aluminium is ideal for more serious projects.