face plate problems

[weisyboy]

gday all

i have an alloy faceplate for my nova1500 that has got a small whip in it (it is worped)

i there any way of getting it back straight?

how could this of happend?

[DJ’s Timber]

I would say you've got 2 options.

1- Get the face re-machined or
2- Bin it

Reasons why it may have happened.

1- going to fast with an out of balanced piece hanging of it
2- doing the screw or bolts that held it onto the work too tight on an uneven surface
3- may have been dropped.

Do yourself a favour and get rid of it and get a steel one.

[scooter]

Er, I've got a steel one that's warped... It is a homemade one, though, and per our illustrious axe wielder, they need to be mounted on a mandrel when being faced off in the metal lathe, I reckon mine was done by just being gripped on the flats on the nut, which has resulted in it being out of whack.

Can get by, just attach a piece of ply to the faceplate, face it true, then take it off, screw it with the true face to your blank and screw the faceplate back where it was (mark the edge or something first so it goes back on the same spot).

Works for me when needed. :) Bit fiddlier than using a true one but workable.


Cheers................Sean

[mobjack68]

gday all

i have an alloy faceplate for my nova1500 that has got a small whip in it (it is worped)

i there any way of getting it back straight?

how could this of happend?

You have a lathe, right?? if you have a carbide tipped tool....mount the faceplate, slow your spindle speed, put your tool rest as close to the faceplate as you can get it (faceplate needs to turn!!) Cut slow, cut steady, cut it true!!!
Even if you don't have a carbide tool, regular HSS tools will cut the alloy, just need to sharpen more often.... You are still going to be dealing with an "out of balance" problem...may or may not be a problem, but the faceplate will be running "true" to the perpendicular line of the spindle/bed....

[Skew ChiDAMN!!]

If you're turning large pieces regularly, DJ's given damned good advice. It just ain't safe.

But if 'tis only a "minor" warp in the faceplate, Scooter's method will work fine for turning smaller pieces. I've done it myself. :)

[rsser]

Garry Pye has heavy Jet faceplates which are good value IMO.

[orraloon]

While we are on face plates, Is there a rule for plate diameter in relation to blank diameter. So far I have turned a 350mm blank on a 90mm plate. I use longer screws on the big ones and so far so good. However something in the back of my mind is saying get a bigger face plate.

Regards
John

[rsser]

While we are on face plates, Is there a rule for plate diameter in relation to blank diameter. So far I have turned a 350mm blank on a 90mm plate. I use longer screws on the big ones and so far so good. However something in the back of my mind is saying get a bigger face plate.

No specific rule that I've heard.

Obviously the greater the overhang the more the fastening is stressed and the better it has to be. That may be critical in the case of irregular blanks, deep blanks and dig-ins :(

The back of the mind's an important place and I'd go with what it's saying. A 90 to 350 ratio would have me reaching for something bigger.

[Frank&Earnest]

You have a lathe, right?? if you have a carbide tipped tool....mount the faceplate, slow your spindle speed, put your tool rest as close to the faceplate as you can get it (faceplate needs to turn!!) Cut slow, cut steady, cut it true!!!
Even if you don't have a carbide tool, regular HSS tools will cut the alloy, just need to sharpen more often.... You are still going to be dealing with an "out of balance" problem...may or may not be a problem, but the faceplate will be running "true" to the perpendicular line of the spindle/bed....

This was my immediate reaction also. But how are you going to "cut it true" by hand? If the warp is deep you could weaken the plate too much and still have a big out of balance problem, if it is minor, would you be able to improve accuracy by much?

I would take dj's advice and try to reverse the warp by using screws on a flat surface (with some help by a hammer:D) to straighten it up as much as possible, then do the final machining with a sanding disk mounted on the tailstock. It might be slower and consume a few disks, but then you are sure that it is true.

[Skew ChiDAMN!!]

No specific rule that I've heard.

Obviously the greater the overhang the more the fastening is stressed and the better it has to be.

One "rule" (of sorts) I use is: the less grain strength, the larger the face plate.

Purely to ensure greater separation of the screws, so if I accidentally align two screws in the "same line of grain" there's less risk of it splitting the blank. So, the minimum safe dia for mounting an Oregon blank is larger than for a piece of Redgum of the same size, even though the Redgum is heavier!

[Calm]

While we are on face plates, Is there a rule for plate diameter in relation to blank diameter.

I reckon no matter what ratio stand to the side when you start the lathe is a really good idea:no::;

Or put your arms out to catch it:;:no:

[weisyboy]

thanks guys

will put up with the small variation for now and invest in a new one latter.