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John Stevenson
10-23-2014, 05:27 PM
I have a mill with Align power feed units on X and Y, they work OK but I have one problem with them.



The feed adjustment knob is in the centre of the forward reverse lever but when using this as a power feed on various jobs going forward, change part, go back, rinse and repeat, even though I take care not to touch the speed knob the handle movement upsets it and alters the feed rate.



Done a web search for this problem but not found anything but I can't be the only person to have this ?



One is worse than the other as the knob is freer. I'm thinking it really needs to have the knob remote from the traverse lever. ?

duckman
10-23-2014, 05:44 PM
Check and see if the knob is touching the shift handle, if it is try moving it out a little, knob may be held with a set screw. Over the years crud can get in between knob and handle causing drag.

Bill Pace
10-23-2014, 06:17 PM
I've got 2 of them and havent had that problem and they are some 5 yrs old. But... they are prone to the potentiometer going out and defaulting to WFO (at least they work) My Z axis units pot has been out for 2-3 yrs now, but I never fine feed with it anyway, just so I dont have to crank on that handle.

ammcoman2
10-23-2014, 06:25 PM
I have often found when starting up it doesn't work. Panic - then realise that the knob has been "nudged" a bit. Have to agree with you.

Geoff

MetalMunger
10-23-2014, 06:33 PM
There are locks made for the potentiometers that are under those knobs:

www.ehcknobs.com/pdfs/catalog/MiltKnob%20p23%20sm.pdf

or replace the whole dang pot. with one that locks.

https://www.sparkfun.com/products/10805

JCHannum
10-23-2014, 08:36 PM
I don't have an Align, but a Chicom clone of one. They cloned it so well that it has the same problem. Thus far, I have lived with it, but I would appreciate suggestions to correct it as well.

_Paul_
10-23-2014, 09:48 PM
Can you "short" the pot on the unit and mount one remote?

plunger
10-24-2014, 01:31 AM
I have an Ajign . I have the same problem.

EVguru
10-24-2014, 06:00 AM
You need to track down some 'damping grease' for the pot shaft.

John Stevenson
10-24-2014, 06:15 AM
So despite not having found any previous complains it appears that it's a common problem, and basically a bad design.
I don't fancy the locking pots as the whole idea of these is to quickly and easily change feed on the move working blind with one hand. Taking your eyes off the ball isn't going to work.

I do have a brand new spare unit I was toying with fitting to the Z knee axis for fine feed. Mine is a Taiwanese Bridgy clone but one size up and it has a three phase motor built in for knee feed but it's only one speed and is for positioning.
My idea when I get a minute is to fit an inverter to this to get adjustable feed hence the Align still being in the box.

When I get a few minutes I'll strip this, see how easy it is to move the pot and swap it for one of the others then work thru.

EVguru
10-24-2014, 06:39 AM
Nye damping grease on ebay; 131328927294

http://www.amazon.co.uk/RCECHO-Tamiya-Friction-Version-Edition/dp/B00K7YYTRO/ref=sr_1_4?ie=UTF8&qid=1414147045&sr=8-4&keywords=damping+grease

http://www.amazon.co.uk/Tarot-Viscosity-Damping-Grease-TL2838/dp/B00MBFKOW6/ref=sr_1_1?ie=UTF8&qid=1414147141&sr=8-1&keywords=damping+grease

http://newgatesimms.co.uk/content/Lubenote_Damping_Grease.pdf