Rapidor Manchester Power Hacksaws

[pendembu]

I have had one of the above saws for some years.It has a clutch and a very large flywheel(about 16ins or so)Its motion is such that it cuts on the backstroke and I have always inserted the blade with the teeth pointing backwards i.e. towards the flywheel. Recently I acquired a newer model powered by a 3 phase geared motor as against the single phase ungeared motor of the older model which uses pulleys to reduce speed.
The newer model has a 12inch flywheel and no clutch.
The newer model appears to cut on the forward stroke which seems odd as I would have expected the cutting stroke to `stretch'the blade rather than `compress' the blade and saw frame. Has anyone got one of these saws(there must be thousands scattered throuhgout the world of different vintage) and which stroke is your cutting stroke? The motion of the frame determines which way the blade is inserted although experiments indicate they will cut with the blade inserted either way but much faster the correct way. Does the direction of rotation of the flywheel matter,i.e. clockwise or anti-clock? I intended to dispose of the older model once the newer one was up and running but it does not seem as efficient as the older version so far but this may be a question of cutting configuration although there are suble design differences at the `head'end.

I would be grateful for any guideance or advice.

[Phil Sutton]

Thinking back to "when I was a lad apprentice"I rather think the power hack saw we had thencut on the "pull" stroke and lifted slightly on the "push"stroke,so the blade ran "backwards".That one was driven by v belts on pulleys.but then we had a newer one,gear driven that worked the other way,ie like a hand driven hacksaw!Seems like you pays your money and you takes your choice! ;D

Phil

[jackrae]

To ensure maximum holding rigidity, the saw should be trying to drive the job into the fixed jaw of the vise. Since most saw vices have their fixed jaw nearest the "mechanism" this means the saw should cut on the pull stroke
Jack

[pendembu]

Thanks Phil.

Your reply bears out the results of my own `experiments'.It seems some subtle alterations were made to the `head' to reverse the direction of cut.

Thanks Jackrae.
For models that cut on the reverse stroke the cutting force is away from the fixed jaw. This may be why the cutting stroke was reversed on later models as the fixed jaw on the Rapidor is the one fartherest from the `head'