Member postings for not done it yet

All I am saying is that doubling the feed rate at constant depth of cut is going to increase the gear train loading more than doubling the depth of cut at a constant ( small) feed rate. If one wants to test the plastic gear, one needs to at least show the effects (if any) of loading that gear and not by just increasing depth of cut.

Work done in moving the carriage horizontally will be reflected in the loading on the gear train. Same amount of material removed could be half the cut and twice the feed. That would load the gear train! Not the way it was done on the vid.

Roy’s reply was was well founded. I might suggest that around 500 surface feet per minute (150m/min) is about 5 times too much. And the lower value would likely be requiring cooling. The feed rate per tooth needs taking into account, too.

Edited to add that Brian would have been more direct re the speed , had he not been typing at the time of your reply.

Edited By not done it yet on 14/01/2018 10:42:16

HowardT,

He was not actually assessing the machine power, just the durability of a plastic gear in the long/cross travel gear train. His aim was to demonstrate the plastic gear at differing loading. I think depth of cut affects the motor loading and feed rate (at constant depth of cut) affects the gear train loading. Him only changing the depth of cut, I believe, was not a fair test of loading the gear train.

A thread for Drummond Shaper users.

The Drummond hand shaper seems to attract some criticism of its rather coarse feed rate. Clearly, with the 20 tooth ratchet gear mine is fitted with (and an 8 tpi screw thread) the minimum feed rate is 6 1/4 thous. A feed rate of two teeth per stroke would likely be more than enough for a hand operated machine?

Some thoughts were, while making the auto-feed components, how do other people’s systems operate in practice.

Can two, or even three, ratchet teeth feed rate be achieved?

Can these feed rates be adjusted, for any reasonably short ram stroke right up to the maximum stroke?

I am currently making a a trial set up (following the drive bracket layout of John’s (Jss) machine as pictured on Gerry’s Shaper restoration thread). After initially thinking the normal bracket was more useful, I have now changed my mind. His machine has a V notch and does away with the short pivot.

I’m hoping I can use a ratchet gear with several more teeth to reduce the minimum feed. I reckon 35 is achievable, perhaps even as many as 40. I am not planning on changing the feed screw and nut!

So, comments and experience please, starting with “is it too coarse?”, “what set up your machine has?”, and responses to the questions above.

TIA.

Which loads the gear train more?

A recent u-toob video by the above has demonstrated making 3D plastic gears and then ‘tested’ one. I reckon increasing the feed rate would stress the gear train more than increasing the depth of cut, but he, and a couple hundred others, reckon increasing the depth of cut with constant feed rate is a fair test for testing a plastic gear in the train.

What do you think?

Edited By not done it yet on 13/01/2018 18:57:46

Use an end mill that cuts straight. Choose one of the correct size. Better, than a twist drill in smaller sizes, any day. As above, if a bigger hole, bore it.

Price does not come into it when deciding whether a necessity or a luxury. If one wants one on a machine not endowed with one, just pay up and fit it. The facts of of pricing now and 50 years ago are irrelevant.

I’ve fitted one to my variable speed spindle (with constant speed motor) on a lathe that was supplied nearly 60 years ago. It was my choice. I will fit one to my mill (will have a VFD as well as six speeds). Again it is my choice.

That word ‘choice’ - not needed but available, therefore a luxury. A handy extra, but not a necessity, therefore a luxury. End of.

Three pages of tacho or no tacho.

Tachos (and VFDs, are a luxury compared to Grandad’s options.

Grandad did OK with six fixed speeds and maybe a back gear. Perhaps he saved hard for a new fangled myford. Or if well heeled, maybe a Raglan. But even with the variable speed Raglan, a tacho was a later luxury and few were ever fitted.

When the one post could well be just asking the way to the ‘for sale’section and a profile which reads:

“Various short lenghs of s/s, steel .ali,brass for sale, also large selection of various spur / stock gears for sale .also small tooling, email or phone for more details.”

makes it surprising and difficult to come to any other conclusion than the seller is here for no other reason than trading. I, personally, would like to see evidence for that decision.

Can’t help, but making an entry in the ‘wanted ads might keep your requirements live without continual ‘bumping’ if you get no assistance today.

Dark ages? Don’t the manufacturers still supply new lathes without QCTPs?

You will gain quite a lot with new tool post.

You will be less rich after the spend, including all the extra tool holders (unless you have facilities to make your own).

You will gain lots and lots of time - think of how many times you need to change tools (and, of course, it takes a finite time to change QC tool holders).

You will have more tool overhang, using a QCTP.

What tool post do you have currently? Perhaps a four way tool post might be a sufficient progress from the dark ages? Then you could have two (at least) tools available most times. Even two tool posts might be an option.

Also, it depends on how much you use your lathe - a measure of the seconds saved per annum, maybe!

Your current set up may be just as good as any alteration. Just your choice, of course.

It may be time to change the thread title to the accepted spelling? It would make it easier for the search facility in the future!

The other fairly obvious trader (profile is all about selling items and only one forum post) has presumably been contacted?

I think vendors should at least have a public profile, so members can perhaps work out if they are private sellers or traders.

Can you join any other yahoo group?

The Drummond group, as an example, is easy going and postings are allowed almost instantly on registering. The Centec forum is really poor in that respect, sometimes taking days for posts to appear.

Finding you could access, or not, another forum might indicate whether it was yahoo, in general, that is causing the problem or the particular DW group level.

Remember car defects are never common and yours is always the only one with that particular fault ever to occur! So may be the typical bull excrement reply from a head in the sand oppo, or an honest response. Your evidence suggests the former, I am afraid!

Don’t know whether this is relevant but I have seen that, rather than parting off with a blade, very narrow rings to close tolerance are better cut with a toolpost grinder with a suitable cutting disc.

There is also at least one vendor who appears to be in the kenwhotisname category Time for JB to look through and weed out?

Perhaps back in the early days, shapers (particularly Adepts?) were, by far, the cheaper option over a relatively expensive milling machine. Also hobby machinists were possibly more ‘manual’ than the modern versions, back in those days, so were not averse to lots of filing?

I am finding I use my mills far more than my lathe these days. It maybe wasn’t always the case.

Edited to add that milling cutters were likely too expensive for most hobbyists and single point cutters were cheap in comparison, but limited in use on a small mill?  Lathe and drill were almost equivalent to a mill?

Edited By not done it yet on 08/01/2018 16:43:29

Why bother with a tacho

It just happens that some lathes have a mechanical variable speed drive, so the motor speed is constant, so not proportional to the speed.

That small hole is close to the axis, so will unlikely to affect the balance of the whole assembly to any discernible degree. Think of how the length of the grub screw would be considered at installation. Interrupted cutting, offset turning, or out of balance parts would have a much greater effect.  Lathe bearing sizes should be designed to be sufficiently robust.  To what degree are most (cheap chinese) chucks dynamically balanced?

However, I would like to be sure the magnet is: a) readily removable and b) unlikely to ever fly off (unlikely but...).

Edited By not done it yet on 08/01/2018 16:08:59

I've always understood that a screw was threaded all the way to the head and a bolt only part way

I’ve always understood that bolts have nuts. Screws need not be threaded all the way along the shank, but bolts are not, as they need to be plain and sized for the hole. Cap screws may be threaded to the head as are coach screws (but not coach bolts).

Softwoods have been traded in metric lengths and volume since the eighties, at least. In the early nineties hardwood was still being traded in cubic feet - but changing over slowly. And, yes 0.3m is still the incremental increase in length. Presumably old mills were set up to cut in feet and instead of changing to 305mm, it was rounded to 300mm as the closest sensible figure.

As far a ‘kids are concerned, there are many out there that still quote their imperial height and weight - but often don’t know how many inches in a foot, or pounds in a stone (and haven’t a clue what an ounce is)!