Member postings for SteveI

Andrew,

You have received a lot of good advice in this thread.

You don't need 3 surface plates to make an excellent result provided that you have a master plate that is good enough. You need 3 plates and a lot of time and effort if you have no confidence in your plates.

You say you have a plate that is good? Is it? How do you know it is good? Have you measured it? In my limited experience if you don't store your cast iron plates at a consistent temperature, (same temperature it was ground or scrapped at) and store it on 3 points, (same three points that it was scraped or ground resting on) you are very unlikely to have a "good" plate. Furthermore did the previous owner of the plate do that?

For the purpose of this thread I define "good" as a surface plate that is flat enough to be used as a reference master plate to scrape another item to. I.e. it needs to repeat so well, that when you blue up you get consistent results. Otherwise you are in for a long and frustrating process.

I have found that to make the process efficient the very best quality granite plate is needed. I suggest granite as you have not confirmed you have a temperature stable workshop to store a large cast iron plate at consistent temperature. Granite is more stable than cast iron. Having said that you should try and keep the room and hence the granite temperature consistent as well and scrape your parts at the same temperature as they will be used. 19 deg or so 24/7 365 is recommended, and keep all direct sun light off the equipment and parts.

If indeed you have a "good" plate stored correctly then just get on with it. If you are roughing in with push scraping you should be scraping to a depth of 0.0002” – 0.0004”. Any shallower and you need to push harder. If you measure your dings, rust pits and any low spots you can estimate how many passes you will need to scrape it out. Shims are your friend and hinging the part will tell you how flat it is and how you are progressing.

If you are just getting started in scraping then just get on with it. Practice practice practice. You have commented on your arm strength. Many professionals and enthusiastic amateurs will place the handle of the scraper in to their stomach/chest and hold the end with 2 hands when roughing and scraping lines. They push with their bodies by rocking the legs. As well as being less tiring this also has the advantage of more control. You also want a bit of spring in your scraper otherwise it is much harder work. The sandvik scrapers are too stiff in many peoples opinion. Much to hard work. If you have one consider to get it thinned out so it is more springy. A friend with a mill can do that for you.

If you are competent and trying to get the plate finished then get it milled, planned, shaped or ground, why scrape for the sake of it? "If it is more than a mm back to the mill!" If ground ask the grinder for a rough dressing of the wheel. and you'll need to rough scrape initially to break up the surface. Ground surfaces do not blue up as nicely as scraped. Having said that on such a small plate why waste a grinding wheel. As has been said already it will be your scraping that determines the final surface result and nothing to do with the initial machining operation.

>>

In case you are just getting started:

1. Scrape it flat within 0.001" minimum. 2 tenths min depth of scrape. Before you move on to improving the PPI and % bearing. Since this is a surface plate I would scrape it flat. within 0.0005". That means no holes! Most likely by that point you are at 10-20 PPI and 50% bearing.

2. Scrape it to a higher PPI and 50% bearing if you so wish. In days of old a surface plate would have been scraped to 40-60 PPI and 50% bearing. Even on a small plate like yours that is a fair bit of work.

These days granite is the material of choice for many good reasons. Although for the hobbyist it is not inexpensive, if you want to scrape more I strongly recommend looking for a good granite surface plate. My piece of granite came out of a scrapped CMM. There are deals out there and granite plates can be reconditioned by the enthusiastic amateur and professionally.

Good luck

Steve

Hi,

Well I had a spare 15 minutes today and after finding no suitable bits of aluminium and thinking hard about machining a cone in the end of the rod, I decided to give it a go holding it in a 1.25" 5C step collet which due to the step stopped the ball bearing being pushed backward. I tightened it up as hard as I could. I had planned to follow Andrew's advice and drill for a 50% thread engagement but unfortunately I did not have a suitably sized drill. I had a 37/64" which I think is~65%. I started with a solid carbide 6mm spotting drill which after about 5mm promptly snapped. I can only assume that the initial hole was off center. I managed to get the tip out and continued with HSS until the 37/64". First part of the job done with golden straw coloured swarf. Does that point to it being 316?

I then screw cut the 5/8"-18 internal thread as I did not have a suitable tap to hand. I'd never screw cut such a short blind hole before so it was an "interesting" job.

In retrospect I think an aluminium pot chuck would have been better. The collet has left a visual mark where it gripped the ball bearing but that won't affect my application. I also think the Chinese ball bearing was not as hard as it should have been. I am hoping that it will be hard enough.

Many thanks for all the advice.

Steve

Hi Martin,

Based on the photos on the net and the original US patent available via google the design calls for on occasion the use of a ring which is placed underneath the ball. I am thinking this is to average out the height changes when moving along a scraped bearing surface or to cope with localised damage/worn area. So the ball needs to be a sufficient diameter and be accurately made. I have guessed at Ø1.25" but have purchased a Ø1" ball bearing as well to try. (I am thinking that when using the tool over a ground surface the ring would not be needed.) So with that in mind a good quality ball bearing was my initial thinking of how best to get a good enough spherical surface.

Thanks,

Steve

EDIT: Also to clarify  I went with stainless to keep the dreaded rust at bay. No other reason. I am building most of it from 303 bar stock plus some cast iron, which will be painted and some  brass.

Edited By SteveI on 11/04/2017 14:46:35

correction for an error in the first post (I can no longer edit it) the planned thread is 5/8-18 UNF. Not 5/8-11 which is UNC.

Andrew,

Thanks. I am not sure from the picture but have you bored out the inside of those split collets to give 2 rings of contact to grip the balls either side of the widest point?

Thanks,

Steve

John,

Yes it is a real ball bearing but of far eastern origin so I do not yet know the hardness. The idea to use the hard ball bearing is that the contact point of the ball to the surface it sits on needs to be a point load (or as near as practical), nice and smooth, and not wear to a flat over time. I am making a kingway tool. Google "kingway alignment tool" and you'll see some pictures.

Your suggestion reminded me of the "pot chuck" that GHT or was it Prof Chaddick wrote about. I don't have any quorn castings gathering dust but I do have a copy of the book so I'll dust that off and give it a read.

thanks,

Steve

Hi,

I need to drill and tap a 1.25" 316 SS ball bearing. The thread needs to be 5/8-11 UNF. I'd like to drill to at least 1/2" depth. This is for a tool I am building.

I have available 3jaw, 4 jaw, and if I need to I could buy a 5C step collet for the job. But the contact area is very small and I am not currently satisfied with the level of grip. I have made a simple back stop in the spindle to stop the ball simply being pushed backwards. ideally I don't want to mark the ball bearing too badly and if I put a burr or scratches on it I'll want to clean it up.

So how best to hold the ball bearing?

If I can't hold it I'll abandon the plan and turn a ball from stock that is qlready drilled and tapped.

Thanks,

Steve

Sandy,

Common sense suggest you must be correct. Mine is a UTH125 and I have no idea how old it is but I provided the S/N to Hofmann in my email. I have no idea if the design has changed over the years either. Perhaps my post was lacking in clarity, I asked Hofmann about all the lubrication specs and specifically the spindle lock and got that answer after 3 attempts. It was like pulling teeth. I never did get an answer about the spindle external taper instead only getting the answer that it was in the manual. I have not spotted the exact spec in the manual. Having said all that it is a very nice dividing head except when I am lifting it!

Steve

Hi,

I had some correspondence with Hofmman in Germany. Regarding the lubrication they told me and I quote:

"use Klüberplex GE 11-680. Manufacturer is Klüber. You can also use other grease with similar specifications."

I also asked about the spindle external taper on the UTH125. The internal taper is MT5 but the external looks like a American short taper D camlock type but it isn't. I did not get a clear answer. I've also asked Rotagrip as they sell a range of backing plates for chucks and they don't know either. The closest I've got is that it is according to some DIN specification but I can't seem to find that information at the moment. Does anyone know? I would very much like to order a backing plate, I'd prefer not to have to make one as face and taper needs to be really precise to work well.

Steve

Nick,

I too have a "modern" boxford. It came with a "standard" set of 9 change wheels to be able to cut ( 39 metric pitches 0.2 - 7mm) (34 English pitches 3.5 - 128 TPI, the tooth counts are:

60, 57, 56, 54, 52, 46, 45, 44, 42

I can't easily make out all the tooth counts you have but you have some of the above for sure. Regarding the spline, I posted a thread a few years back on this and it turned out to be pretty well responded to. The thread helped me! I'll try and link to it:

**LINK**

NB I also have the T slotted boring table for the X10. I've never seen another but to be fair I don't spend time looking, PM me with your email if your interested in details. It would not be hard to make but you'll need a fair sized lump of cast iron.

Steve

Brian,

Ask the seller to try USPS flat rate boxes. I've found that to be about the best value. Don't quote me but I recall the Insurance is max US$200 but you are well under that. In the past I've paid $60 for a 65Ib box of goodies.

Steve

Edited By SteveI on 07/02/2017 16:43:41

Apologies to the OP and Nigel in particular. I can't read the original post or the book correctly. Sorry. I was not looking at the tramming tests. My mistake.

Steve

Edited By SteveI on 28/01/2017 17:19:56

Nigel, is that a typo, otherwise I am shocked. Unless these machines were enormous you are well outside any recognised (Schlesinger) limits. Furthermore in the spriit of a recent thread about disagreement it is not sound advice to give to someone on a model engineer forum, i.e. with a focus on smaller machine tools, and specifically a Warco WM-18. Do you mind telling us where you worked and when so we can avoid or proceed with caution with any and all machines from that maker?

Even if the OP's work planned could accept those tolerances it would still be a poor quality machine and should be priced accordingly. I.e. scrap prices for a complete rebuild. I will be shocked to learn that Warco knowingly delivered out milling machines built to your stated tolerances.

Steve

Hi,

i just thought it may be interesting to see the quality of work that a motivated person can do after one of these courses and some elbow grease Jan Sverre is ongoing with a complete restoration/rebuild of a Myford 7 (not a Myford man myself so not sure on the exact model) and also a Raglan.

Here is the myford as rescued: https://www.youtube.com/watch?v=6OfAFhj2eQ0

and here it is after finished with the bed: **LINK**

I understand from Jan Sverre that he is doing the Myford completely with hand scraping. No expensive power scraper required. Although they do come up regularly on well known auction sites. Jan Sverre is much further along than just the bed and many more videos are available on this, the raglan and a very impressive schaublin 52 mill rebuild:

**LINK**

Steve

Edited to get the links to work.

Edited By SteveI on 17/01/2017 09:23:41

Thats nothing a nice DRO wont solve for you.

Congrats with the new lathe.

Hi,

Do these controllers support servo motors? encoder inputs? tool changers? 4th axis? I am inclined to think they must since they are used industrially in china. Is there any one using it on a bridgeport interact or similar type machine?

Thanks,

Steve

Neil,

In the rcgroups thread that Michael linked to there is a comment that these collets are the same as those used on the older (10" grinding wheel size) myford grinders. I do not know if that is true. However those collets are available here:

http://www.jubileemactools.com/website-pages/MYFORD_MG12_Collets_(Older_Type)_G2459P__NEW-p-439.html

They are however referenced as type "G2459P". NB the later Myford grinders use Hardinge 4C collets which are not the same.

EDIT: Just seen that the G2459P collets look nothing like the MA99E. It would seem the rcgroups thread has inaccurate information! What a shock for the internet. 

Edited By SteveI on 29/12/2016 10:45:24

Hi,

Two thoughts... Firstly well done for seeing this through and coming out the other side still sane. Second of all with the skills you have exhibited why did you not consider an older western machine that may need some TLC rather than a Chinese import?

Steve

Bazyle,

A "Spannzangenaufnahme" MK5 - 5C

Not sure why I wrote bush should have wrote adapter.

Steve

Bazyle,

Your right I suppose we need to understand what was mean't by the OP. AFAIK:

"Old" boxfords: 3MT spindle bore. 5C won't fit. Better off with the 3C collets that were sold as standard accessories

"Old" Boxfords VSL L00 spindle nose so I think a 5MT. Go straight to ebay.de but the 5MT to 5C bush and then on to the draw tube. Or look for a L00 mount 5C collet chuck. They do come up on ebay.com.

"New" Boxfords e.g. the Industrial 11.30, D1-3 spindle with 4 1/2 MT spindle bore. Equals a bit of pain or a lot of luck see above post for options.

Steve