Member postings for Pete Rimmer

I have a chart that's laminated and stuck on my wall. It's tailored to my own hobbing machine and common pitches I might cut but it's a very good quick reference. You could easily knock up your own chart in excel/calc.

Depth of cut you should take from the cutter - if it's a hob you should certainly take the DOC from the cutter because there are different types. Brown and Sharp hobs have different DOC to others and there seems to be no fixed rule for the older ones at least.

Edited By Pete Rimmer on 24/08/2022 06:52:03

Double post

Edited By Pete Rimmer on 23/08/2022 18:36:56

Nitrous oxide increases the amount of oxygen in the intake charge, allowing more fuel to be burned. Simple as that. Gains from increasing the density of the intake charge by cooling are minimal.

Yes that's correct for pitch diameter but not outside diameter.

I have glued several poly-vee belts with superglue and a long splice and none have parted so far.

Buy the glue from a double glazing shop. You can get a big pot of it for about 6 quid and it's slow setting stuuf, very strong compared to the thin quick-setting ones.

Ronnie Pickering?

Correct I was not suggesting milling without a drawbar, just a loosened one.

Well I wouldn't condone running it at 2000rpm but sooner or later you're going to have a tool come loosein the taper. I guess it all depends on what you regard as 'safe'. Some people won't use a 9" grinder full stop because they don't regard them as 'safe'. I'm more than comfortable with it.

Probably best to explore other avenues TBH, my reply was very much tongue-in-cheek.

Loosen the drawbar and start cutting it'll soon come loose then

On my PC hitting print screen opens up the snipping tool and you instantly get the option for rectangular, freeform, window or full screen snip.

For single phase input L1 is live and L2 is neutral, Earth goes to the earth terminal or point on the chassis marked as such and L3 is left not connected. It may have a link plate from L2 if it does, leave that alone.

Hell would freeze over before I would take money to let some random use my machines. When people pay for something they think that it gives them free license to do as they please.

I you cared to pop down to me in Gravesend I would do a quick evaluation of your plate. You could bring the table and I'd do that too.

William,

A 1MOD 18T gear will probably do what you are looking for. 1.8" pitch is 1.011 module. The pressure angle will be incorrect unless you're lucky enout to find a 14.5PA 1 MOD gear but that should not matter overly much just for a handweel traversing gear.

Edited By Pete Rimmer on 07/08/2022 10:21:02

Your setup there will work but it will tend to read what's under the front end of the scriber block rather than what's under the pointer. Shorten it up by pulling the rod back through the clamp a bit.

A basic repeat-o-meter is simple enough to make. I made mine from a chunk of cast iron with the corner cut off and using a stanley blade as a hinge. Took a few hours and it works very well.

repeat-o-meter

I have several of Lamb's cast straight edges. He will supply them bare or machined ready to scrape.

The casting quality is very good and it's good iron for scraping. Not nearly as hard as the one in the pic further up which was a devil to scrape without chatter. These are ideal for the home user, if you can find a reference to scrape them from.

You can't put 3/4" up the hole on a ML7 but you could hold one end in a 3- or 4-jaw and run the other in a fixed steady. It would turn on it's own axis then with no need for clocking in. The two diameters would be completely concentric.

If you look at my pic at full size in the album you'll see that the centre section is quite flat so by measuring from the top flat which is only half the length of the table you'll get a pretty good result. The ends see very little bearing so there's a section at about 25% and 75% where the surface takes quite a change.

In my pic from 1 to 6 (tenths) is half a thou difference then 6 to 12 is 6 tenths difference but over 2.5 times the length. the centre is straighter than the ends.

Also account for the fact that the micrometer measurements are not affected by gravity but DTI measurements are. The table is thin so will droop depending on which way up it's held. If it's flat upturned on the plate which it seems to be, it will be negligible.

Edited By Pete Rimmer on 05/08/2022 10:27:52

You can evaluate most small surface grinder tables just with a micrometer. So long as the mic can span from top to way you can make it as flat as the top to within a couple of tenths at least. It'll be fatter at the ends and more worn in the middle and the bottom ways will match that bow. You'll be able to see that by the wear ridges left behind.

Get a micrometer and go along the ways every couple of inches. Measure the table thickness and mark it on the way with a sharpie. Remove the wear ridges and high spots with a file if you have to. If your ends are 5 thou higher than the middle don't fanny around trying to scrape them - get a good large flat file and file a few thou off. It's a lot faster thn scraping and so long as you carefully keep track so you don't overshoot you can get within scraping distance very quickly. My eagle table had the two long ways raised higher than any other features so I just laid the file across both and it kept them planar. It's not so difficult as you might imagine.

The numbers below are tenths of a thou.

If you're near Kent I could give you some pointers or even lend a straight edge.

Edited By Pete Rimmer on 03/08/2022 22:21:59

Yep it's slow and hard work but going too far isn't as easy as you at first think..

Half-thou deep scrapes are not normal more like 2 tenths. So if you think that you'd have trouble milling off only 1 thou of cast iron, that's a good 4-5 rounds of scraping.

What tight spots are you trying to get into? Ways inherently have open ends so I guess you must mean a dovetail? If so then just get yourself a big mechanical hacksaw blade and use it manually to cut a healthy relief in the corner.

Like most things there are a number of ways of doing this stuff. What I would advise is don't strive for perfection. So what if you dig a few double-depth holes in the work? It'll still function as intended. So what if the best flatness you can achieve is 1 thou? That's 5 times better than the 5 thou you have now.